Posts tagged depression
Articles and news from the latest research reports.
Imaging in mental health and improving the diagnostic process
What are some of the most troubling numbers in mental health? Six to 10 — the number of years it can take to properly diagnose a mental health condition. Dr. Elizabeth Osuch, a Researcher at Lawson Health Research Institute and a Psychiatrist at London Health Sciences Centre and the Department of Psychiatry at Western University, is helping to end misdiagnosis by looking for a ‘biomarker’ in the brain that will help diagnose and treat two commonly misdiagnosed disorders.
Major Depressive Disorder (MDD), otherwise known as Unipolar Disorder, and Bipolar Disorder (BD) are two common disorders. Currently, diagnosis is made by patient observation and verbal history. Mistakes are not uncommon, and patients can find themselves going from doctor to doctor receiving improper diagnoses and prescribed medications to little effect.
Dr. Osuch looked to identify a ‘biomarker’ in the brain which could help optimize the diagnostic process. She examined youth who were diagnosed with either MDD or BD (15 patients in each group) and imaged their brains with an MRI to see if there was a region of the brain which corresponded with the bipolarity index (BI). The BI is a diagnostic tool which encompasses varying degrees of bipolar disorder, identifying symptoms and behavior in order to place a patient on the spectrum.
What she found was the activation of the putamen correlated positively with BD. This is the region of the brain that controls motor skills, and has a strong link to reinforcement and reward. This speaks directly to the symptoms of bipolar disorder. “The identification of the putamen in our positive correlation may indicate a potential trait marker for the symptoms of mania in bipolar disorder,” states Dr. Osuch.
In order to reach this conclusion, the study approached mental health research from a different angle. “The unique aspect of this research is that, instead of dividing the patients by psychiatric diagnoses of bipolar disorder and unipolar depression, we correlated their functional brain images with a measure of bipolarity which spans across a spectrum of diagnoses.” Dr. Osuch explains, “This approach can help to uncover a ‘biomarker’ for bipolarity, independent of the current mood symptoms or mood state of the patient.”
Moving forward Dr. Osuch will repeat the study with more patients, seeking to prove that the activation of the putamen is the start of a trend in large numbers of patients. The hope is that one day there could be a definitive biological marker which could help differentiate the two disorders, leading to a faster diagnosis and optimal care.
In using a co-relative approach, a novel method in the field, Dr. Osuch uncovered results in patients that extend beyond verbal history and observation. These results may go on to change the way mental health is diagnosed, and subsequently treated, worldwide.
What Color is Your Night Light? It May Affect Your Mood
Study Finds Red Light Least Harmful, While Blue Light is Worst
When it comes to some of the health hazards of light at night, a new study suggests that the color of the light can make a big difference.
In a study involving hamsters, researchers found that blue light had the worst effects on mood-related measures, followed closely by white light.
But hamsters exposed to red light at night had significantly less evidence of depressive-like symptoms and changes in the brain linked to depression, compared to those that experienced blue or white light.
The only hamsters that fared better than those exposed to red light were those that had total darkness at night.
The findings may have important implications for humans, particularly those whose work on night shifts makes them susceptible to mood disorders, said Randy Nelson, co-author of the study and professor of neuroscience and psychology at The Ohio State University.
“Our findings suggest that if we could use red light when appropriate for night-shift workers, it may not have some of the negative effects on their health that white light does,” Nelson said.
The study appears in the Aug. 7, 2013, issue of The Journal of Neuroscience.
The research examined the role of specialized photosensitive cells in the retina — called ipRGCs — that don’t have a major role in vision, but detect light and send messages to a part of the brain that helps regulate the body’s circadian clock. This is the body’s master clock that helps determine when people feel sleepy and awake.
Other research suggests these light-sensitive cells also send messages to parts of the brain that play a role in mood and emotion.
“Light at night may result in parts of the brain regulating mood receiving signals during times of the day when they shouldn’t,” said co-author Tracy Bedrosian, a former graduate student at Ohio State who is now a postdoctoral researcher at the Salk Institute. “This may be why light at night seems to be linked to depression in some people.”
What people experience as different colors of light are actually lights of different wavelengths. The ipRGCs don’t appear to react to light of different wavelengths in the same way.
“These cells are most sensitive to blue wavelengths and least sensitive to red wavelengths,” Nelson said. “We wanted to see how exposure to these different color wavelengths affected the hamsters.”
In one experiment, the researchers exposed adult female Siberian hamsters to four weeks each of nighttime conditions with no light, dim red light, dim white light (similar to that found in normal light bulbs) or dim blue light.
They then did several tests with the hamsters that are used to check for depressive-like symptoms. For example, if the hamsters drink less-than-normal amounts of sugar water — a treat they normally enjoy — that is seen as evidence of a mood problem.
Results showed that hamsters that were kept in the dark at night drank the most sugar water, followed closely by those exposed to red light. Those that lived with dim white or blue light at night drank significantly less of the sugar water than the others.
After the testing, the researchers then examined the hippocampus regions of the brains of the hamsters.
Hamsters that spent the night in dim blue or white light had a significantly reduced density of dendritic spines compared to those that lived in total darkness or that were exposed to only red light. Dendritic spines are hairlike growths on brain cells that are used to send chemical messages from one cell to another.
A lowered density of these dendritic spines has been linked to depression, Nelson said.
“The behavior tests and changes in brain structure in hamsters both suggest that the color of lights may play a key role in mood,” he said.
“In nearly every measure we had, hamsters exposed to blue light were the worst off, followed by those exposed to white light,” he said. “While total darkness was best, red light was not nearly as bad as the other wavelengths we studied.”
Nelson and Bedrosian said they believe these results may be applicable to humans.
In addition to shift workers, others may benefit from limiting their light at night from computers, televisions and other electronic devices, they said. And, if light is needed, the color may matter.
“If you need a night light in the bathroom or bedroom, it may be better to have one that gives off red light rather than white light,” Bedrosian said.
Researchers uncover brain molecule regulating human emotion, mood
A RIKEN research team has discovered an enzyme called Rines that regulates MAO-A, a major brain protein controlling emotion and mood. The enzyme is a potentially promising drug target for treating diseases associated with emotions such as depression.
Monoamine oxidase A (MAO-A) is an enzyme that breaks down serotonin, norephinephrine and dopamine, neurotransmitters well-known for their influence on emotion and mood. Nicknamed the “warrior gene”, a variant of the MAOA gene has been associated with increased risk of violent and anti-social behavior.
While evidence points to a link between MAO-A levels and various emotional patterns, however, the mechanism controlling MAO-A levels in the brain has remained unknown.
Now, a research team headed by Jun Aruga at the RIKEN Brain Science Institute has shown for the first time that a ligase named Rines (RING finger-type E3 ubiquitin ligase) regulates these levels. Their research shows that mice without the Rines gene exhibit impaired stress responses and enhanced anxiety, controlled in part through the regulation of MAO-A levels. The study is published today in Journal of Neuroscience.
As the first study to demonstrate regulation of MAO-A protein via the ubiquitin proteasomal system, this research presents a promising new avenue for analyzing the role of MAO-A in brain function. Further research promises insights into the treatment of anxiety, stress-related disorders and impaired social functions.
Reference:
Miyuki Kabayama, Kazuto Sakoori, Kazuyuki Yamada, Veravej G. Ornthanalai, Maya Ota, Naoko Morimura, Kei-ichi Katayama, Niall P. Murphy, and Jun Aruga. “Rines E3 Ubiquitin Ligase Regulates MAO-A Levels and Emotional Responses.” The Journal of Neuroscience, 2013.
![The Search for the Best Depression Treatment
Brain scans, blood samples, and other diagnostic tests could one day direct doctors to the best treatments for depression patients and uncover the biological basis of the condition.
When someone is diagnosed with depression, patient and doctor often begin a long trial-and-error process of testing different treatments. Sometimes they work, sometimes they don’t, so patients may try several options before finding the best one. But in the future, a brain scan, blood test, or some combination could help guide doctors to the best drugs, or lead them to suggest talk therapy.
Recently, Emory University researcher Helen Mayberg reported that a PET scan, a commonly used imaging method, can reveal whether a patient will respond better to an antidepressant or cognitive behavioral therapy. And in May, Medscape reported that David Mischoulon of Massachusetts General Hospital presented findings that the amount of a particular protein in the blood of depression patients could indicate whether a patient would do better by adding a form of folic acid to his or her treatment.
A key goal of such research is to distinguish between causes of depression. “The presence of certain biomarkers might give us a clue whether [a particular patient’s] depression is truly biologically driven, or whether it is depression like sadness over an event,” says Mischoulon. “If we can identify people who have these biological bases, it might suggest these patients might do better with medications, as opposed to psychotherapies or meditation.”
According to the World Health Organization, depression is the leading cause of disability globally. Many people do not seek or do not have access to treatment, and among those who do, fewer than 40 percent of depression patients improve with the first type of treatment they try. The problem is not that treatments like antidepressants and cognitive behavioral therapy don’t work, it’s that no one treatment works for every patient. Researchers from many disciplines, from neuroscience to genomics, are studying this complex disorder, which likely represents many different conditions with unique origins and treatments. Large clinical trials to predict a patient’s response to therapy or drugs based on brain or body biomarkers could improve treatment for future patients and perhaps uncover a clearer understanding of depression’s origins.
“You see now a number of big studies on predictive biomarkers,” says Mayberg, who has pioneered pacemaker-like implants as a treatment for severe cases of depression. She’s also involved in a large study of patients who will be treated with antidepressants or cognitive behavioral therapy based on brain scans. “It’s going to be interesting over the next year or two to see how this plays out,” she says. One question will be whether researchers will be able to identify markers that are both unambiguous but also practical to test. Brain scans may be the best place to start, she says, because they focus on the origin of the condition, but once good biomarkers are identified via brain scan, surrogates found in the blood may provide a simpler and more affordable option.
One challenge for researchers is that depression is probably a conglomeration of many diseases, says Madhukar Trivedi, a University of Texas Southwestern researcher heading a large trial that is trying to distinguish patients who respond better to one type of antidepressant compared to another. “There are a lot of subtypes in depression, so any given marker, whether genetic, protein, imaging, or EEG, ends up accounting for only a small percentage of variance for any group of patients,” says Trivedi.
If these researchers are successful, they could dramatically change how depression is treated and perhaps diagnosed. Doctors in the United States use the Diagnostic and Statistical Manual of Mental Disorders, or DSM, to diagnose depression. The diagnoses are largely based on the collection of symptoms presented or described by patients. In May, the head of the National Institute of Mental Health, Thomas Insel, announced that his institution would focus its research in areas other than the categories presented by the DSM. “Patients with mental disorders deserve better,” he said.
Bruce Cuthbert is heading the NIMH’s project to establish new ways of studying mental illness and potentially to improve future versions of the DSM by more precisely identifying the brain abnormalities in various diseases, including depression. The idea behind the project is to map out the genetic, circuit, and cognitive aspects of mental illness and to focus on individual features of disorders instead of clinical diagnoses. It could provide the information necessary to improve the DSM so that it is based on neuroscience and not just collections of symptoms. “In the future, we might define the disorders differently, or we might not. But this project will provide a framework to look at neural systems and how they operate and how that contributes to disease,” says Cuthbert.
Perhaps more immediately, the NIMH project could help researchers tune clinical trials of drugs to the right patients by focusing on discrete symptoms. For example, anhedonia, the inability to feel pleasure or seek pleasure, is a major symptom of depression, but it is also found in other patients, such as those with schizophrenia. By recruiting patients with measurable anhedonia, drug developers may be more likely to succeed in clinical trials than if they focused only on depression patients, says Cuthbert.
The NIMH project could also help to identify biomarkers of depression. “It could give us a structure to look at the pathology through different markers of the disease,” says Trivedi. “The goal is fantastic, but the proof is going to come in doing it.”](http://40.media.tumblr.com/2cee06d8ba637a69d1ed2f2d29d4c882/tumblr_mr0drrDP3b1rog5d1o1_500.jpg)
The Search for the Best Depression Treatment
Brain scans, blood samples, and other diagnostic tests could one day direct doctors to the best treatments for depression patients and uncover the biological basis of the condition.
When someone is diagnosed with depression, patient and doctor often begin a long trial-and-error process of testing different treatments. Sometimes they work, sometimes they don’t, so patients may try several options before finding the best one. But in the future, a brain scan, blood test, or some combination could help guide doctors to the best drugs, or lead them to suggest talk therapy.
Recently, Emory University researcher Helen Mayberg reported that a PET scan, a commonly used imaging method, can reveal whether a patient will respond better to an antidepressant or cognitive behavioral therapy. And in May, Medscape reported that David Mischoulon of Massachusetts General Hospital presented findings that the amount of a particular protein in the blood of depression patients could indicate whether a patient would do better by adding a form of folic acid to his or her treatment.
A key goal of such research is to distinguish between causes of depression. “The presence of certain biomarkers might give us a clue whether [a particular patient’s] depression is truly biologically driven, or whether it is depression like sadness over an event,” says Mischoulon. “If we can identify people who have these biological bases, it might suggest these patients might do better with medications, as opposed to psychotherapies or meditation.”
According to the World Health Organization, depression is the leading cause of disability globally. Many people do not seek or do not have access to treatment, and among those who do, fewer than 40 percent of depression patients improve with the first type of treatment they try. The problem is not that treatments like antidepressants and cognitive behavioral therapy don’t work, it’s that no one treatment works for every patient. Researchers from many disciplines, from neuroscience to genomics, are studying this complex disorder, which likely represents many different conditions with unique origins and treatments. Large clinical trials to predict a patient’s response to therapy or drugs based on brain or body biomarkers could improve treatment for future patients and perhaps uncover a clearer understanding of depression’s origins.
“You see now a number of big studies on predictive biomarkers,” says Mayberg, who has pioneered pacemaker-like implants as a treatment for severe cases of depression. She’s also involved in a large study of patients who will be treated with antidepressants or cognitive behavioral therapy based on brain scans. “It’s going to be interesting over the next year or two to see how this plays out,” she says. One question will be whether researchers will be able to identify markers that are both unambiguous but also practical to test. Brain scans may be the best place to start, she says, because they focus on the origin of the condition, but once good biomarkers are identified via brain scan, surrogates found in the blood may provide a simpler and more affordable option.
One challenge for researchers is that depression is probably a conglomeration of many diseases, says Madhukar Trivedi, a University of Texas Southwestern researcher heading a large trial that is trying to distinguish patients who respond better to one type of antidepressant compared to another. “There are a lot of subtypes in depression, so any given marker, whether genetic, protein, imaging, or EEG, ends up accounting for only a small percentage of variance for any group of patients,” says Trivedi.
If these researchers are successful, they could dramatically change how depression is treated and perhaps diagnosed. Doctors in the United States use the Diagnostic and Statistical Manual of Mental Disorders, or DSM, to diagnose depression. The diagnoses are largely based on the collection of symptoms presented or described by patients. In May, the head of the National Institute of Mental Health, Thomas Insel, announced that his institution would focus its research in areas other than the categories presented by the DSM. “Patients with mental disorders deserve better,” he said.
Bruce Cuthbert is heading the NIMH’s project to establish new ways of studying mental illness and potentially to improve future versions of the DSM by more precisely identifying the brain abnormalities in various diseases, including depression. The idea behind the project is to map out the genetic, circuit, and cognitive aspects of mental illness and to focus on individual features of disorders instead of clinical diagnoses. It could provide the information necessary to improve the DSM so that it is based on neuroscience and not just collections of symptoms. “In the future, we might define the disorders differently, or we might not. But this project will provide a framework to look at neural systems and how they operate and how that contributes to disease,” says Cuthbert.
Perhaps more immediately, the NIMH project could help researchers tune clinical trials of drugs to the right patients by focusing on discrete symptoms. For example, anhedonia, the inability to feel pleasure or seek pleasure, is a major symptom of depression, but it is also found in other patients, such as those with schizophrenia. By recruiting patients with measurable anhedonia, drug developers may be more likely to succeed in clinical trials than if they focused only on depression patients, says Cuthbert.
The NIMH project could also help to identify biomarkers of depression. “It could give us a structure to look at the pathology through different markers of the disease,” says Trivedi. “The goal is fantastic, but the proof is going to come in doing it.”
Surgical Anesthetic Appears to Treat Drug-Resistant Depression
More study is needed, but isoflurane might provide alternative to electroconvulsive therapy
Although electroconvulsive therapy (ECT) has long been considered the most effective treatment of medication-resistant depression, millions of people who could benefit don’t take advantage of it because of the treatment’s side effects and public misperception of the procedure.
If the results of a campus-wide collaboration of University of Utah researchers are borne out by larger studies and trials, patients with refractory depression might one day have an alternative that is as effective as ECT but without the side effects – the surgical anesthetic drug isoflurane.
“We need to expand our research into a larger, multicenter trial, but if the results of our pilot study pan out, it would change the face of treating depression,” says Howard R. Weeks, M.D., assistant professor of psychiatry and first author on a study published July 26, 2013, in PLOS ONE online.
Also known as shock therapy, ECT is effective in 55 percent to 90 percent of depression cases, with significant reductions in symptoms typically occurring within two to four weeks. When medications work, they can take six to eight weeks to become effective. But ECT is associated with side effects including amnesia, concentration and attention problems, and other cognitive issues. Many people also mistakenly believe ECT is painful and causes brain damage, which has given the treatment a social stigma that makes millions of patients reluctant to have it. Isoflurane potentially offers an alternative to ECT that could help many of those people, according to Weeks and his colleagues from eight University of Utah departments and programs.
In a pilot study with 20 patients who received ECT treatments compared to eight patients who received the isoflurane treatments, the researchers found that both therapies provided significant reduction in symptoms of depression. Immediately following the treatments, ECT patients showed declines in areas of memory, verbal fluency, and processing speed. Most of these ECT-related deficits resolved by four weeks. However, autobiographical memory, or recall of personal life events, remained below pretreatment levels for ECT patients four weeks after the treatment. In contrast, the patients treated with isoflurane showed no real impairment but instead had greater improvements in cognitive testing than ECT patients both immediately and four weeks after the treatments.
In the mid-1980’s, researchers in Europe studied isoflurane as a potential depression therapy. Later studies by other scientists failed to confirm the results of the original work and isoflurane research fell out of favor. But these later studies didn’t adhere to the first study’s protocol regarding type of anesthetic, dosing size and number of treatments, according to Weeks, and he believes that’s why isoflurane’s antidepressant effects weren’t confirmed in subsequent trials. For their research, Weeks and his University of Utah colleagues followed the original study’s protocol.
“Our data reconfirm that isoflurane had an antidepressant effect approaching ECT with less adverse neurocognitive effects, and reinforce the need for a larger clinical trial,” the researchers wrote.
Researchers don’t know what produces the relief of depression symptoms from ECT or isoflurane. Weeks believes further research might identify a molecular pathway that both therapies target and is responsible for the improvement in depression. One common effect of both ECT and isoflurane treatments is a brief state of low electrical activity in which the brain becomes unusually quiet. ECT induces a seizure to reach that state, but isoflurane does not. After inhaling the anesthesia, patients are “under” for about 45 minutes, with 15 minutes of that time being a deep state of unconsciousness, according to Weeks. This period of electrical rest for the brain may be a potential explanation for why ECT and isoflurane improve depression.
If isoflurane proves to be a viable alternative to ECT, a device invented by three University of Utah anesthesiology faculty members can make the anesthetic an even more attractive therapy. The Aneclear™ device (Anecare, Salt Lake City, UT) invented by Dwayne R. Westenskow, Ph.D., Derek J. Sakata, M.D., and Joseph A. Orr, Ph.D., from the University of Utah Department of Anesthesiology, uses hyperventilation and allows patients to rebreathe their own carbon dioxide (C02). Hyperventilation removes anesthesia from the lungs and C02 encourages blood flow to the brain, which encourages quicker removal of anesthetic. The Aneclear™ also minimizes or even eliminates vomiting, nausea, and extreme fatigue that some patients experience from anesthesia.
“With the Aneclear™, we can wake people up from the anesthesia much quicker,” Weeks says. “This makes the treatment a potentially viable clinical treatment by reducing the time required in an operating room.”
Weeks and his co-researchers now are looking for grants to fund a larger study that will include several U.S. centers.
(Source: healthcare.utah.edu)
Biochemical mapping helps explain who will respond to antidepressants
Duke Medicine researchers have identified biochemical changes in people taking antidepressants – but only in those whose depression improves. These changes occur in a neurotransmitter pathway that is connected to the pineal gland, the part of the endocrine system that controls the sleep cycle, suggesting an added link between sleep, depression and treatment outcomes. The study, published on July 17, 2013, in the journal PLOS ONE, uses an emerging science called pharmacometabolomics to measure and map hundreds of chemicals in the blood in order to define the mechanisms underlying disease and to develop new treatment strategies based on a patient’s metabolic profile.
"Metabolomics is teaching us about the differences in metabolic profiles of patients who respond to medication, and those who do not," said Rima Kaddurah-Daouk, PhD, associate professor of psychiatry and behavioral sciences at Duke Medicine and leader of the Pharmacometabolomics Research Network.
"This could help us to better target the right therapies for patients suffering from depression who can benefit from treatment with certain antidepressants, and identify, early on, patients who are resistant to treatment and should be placed on different therapies."
Major depressive disorder – a form of depression characterized by a severely depressed mood that persists two weeks or more – is one of the most prevalent mental disorders in the United States, affecting 6.7% of the adult population in a given year.
Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants for major depressive disorder, but only some patients benefit from SSRI treatment. Others may respond to placebo, while some may not find relief from either. This variability in response creates dilemmas for treating physicians where the only choice they have is to test one drug at a time and wait for several weeks to determine if a patient is going to respond to the specific SSRI.
Recent studies by the Duke team have used metabolomics tools to map biochemical pathways implicated in depression and have begun to distinguish which patients respond to treatment with an SSRI or placebo based on their metabolic profiles. These studies have pointed to several metabolites on the tryptophan metabolic pathway as potential contributing factors to whether patients respond to antidepressants.
Tryptophan is metabolized in different ways. One pathway leads to serotonin and subsequently to melatonin and an array of melatonin-like chemicals called methoxyindoles produced in the pineal gland. In the current study, the researchers analyzed levels of metabolites within branches of the tryptophan pathway and correlated changes with treatment outcomes.
Seventy-five patients with major depressive disorder were randomized to take sertraline (Zoloft) or placebo in the double-blind trial. After one week and four weeks of taking the SSRI or placebo, the researchers measured improvement in symptoms of depression to determine response to treatment, and blood samples were taken and analyzed using a metabolomics platform build to measure neurotransmitters.
The researchers observed that 60 percent of patients taking the SSRI responded to the treatment, and 50 percent of those taking placebo also responded. Several metabolic changes in the tryptophan pathway leading to melatonin and methoxyindoles were seen in patients taking the SSRI who responded to the treatment; these changes were not found in those who did not respond to the antidepressant.
The results suggest that serotonin metabolism in the pineal gland may play a role in the underlying cause of depression and its treatment outcomes, based on the biochemical changes that were seen to be associated with improvements in depression.
"This study revealed that the pineal gland is involved in mechanisms of recovery from a depressed state," said Kaddurah-Daouk. "We have started to map serotonin which is believed to be implicated in depression, but now realize that it may not be serotonin itself that is important in depression recovery. It could be metabolites of serotonin that are produced in the pineal gland that are implicated in sleep cycles.
"Shifting utilization of tryptophan metabolism from kynurenine to production of melatonin and other methoxyindoles seems important for treatment response but some patients do not have this regulation mechanism. We can now start to think about ways to correct this."
The identification of a metabolic signature for patients who have a milder form of depression and who can improve with use of placebo is critically important for streamlining clinical trials with antidepressants. The Duke team is the first to start to define in depth early biochemical effects of treatment with SSRI and placebo, and a molecular basis for why antidepressants take several weeks to start showing benefit.
In future studies, researchers may collect blood samples from patients during both the day and night to define how the circadian cycle, changes in sleep patterns, neurotransmitters and hormonal systems are modified in those who respond and do not respond to SSRIs and placebo. This can lead to more effective treatment strategies.
(Source: dukehealth.org)
Brain Structural Deficits May Contribute to Increased Functional Connections Between Brain Regions Implicated in Depression
Major depressive disorder is associated with a dysregulation of brain regions including the prefrontal cortex and limbic system. The relationship between structural and functional abnormalities in these brain regions in depressed patients is far from clear. However, both types of changes are assumed to underlie the symptoms of this disorder.
This lack of understanding prompted Dr. Bart de Kwaasteniet at the Academic Medical Center in Amsterdam and his colleagues to use a multimodal neuroimaging approach to further investigate this relationship.
The researchers, led by Professor Damiaan Denys, recruited 18 patients with major depressive disorder and 24 healthy individuals, all of whom underwent multiple neuroimaging scans. They specifically focused on the structural and functional connectivity between the subgenual anterior cingulate cortex (ACC) and the medial temporal lobe, two regions that are connected by a white matter tract called the uncinate fasciculus. These regions are known to be involved in the regulation of emotion and memory.
de Kwaasteniet explained their findings: “We identified decreased structural integrity of the uncinate fasciculus connecting the medial temporal lobe and the subgenual ACC. Furthermore, we identified an increased functional connection between these regions in major depression relative to controls. Importantly, we identified a negative correlation between the integrity of this white matter tract and the functional connection between the subgenual ACC and bilateral hippocampus in major depression.”
These results suggest that structural disturbances in the uncinate fasciculus contribute to abnormally high functional interactions among brain circuits associated with the symptoms of depression. “This leads to the hypothesis that abnormalities in brain structure lead to differences in connectivity between brain areas in depressive disorder,” added de Kwaasteniet.
However, they also hypothesized that the reverse may be true as well. In other words, that the increased functional connectivity among these brain regions leads to structural changes in the brain’s white matter fibers by means of an abnormally increased signal transduction. This hypothesis is supported by recent studies in schizophrenia which suggest that circuit hyperactivity may be a predictor of subsequent cortical atrophy.
"This interesting study suggests that abnormalities in the structural connections between brain regions, the white matter, are associated with abnormal activity within a brain circuit implicated in the symptoms of depression. This observation raises an important question about the implications of treating the circuit functional abnormalities without fixing the underlying brain structure," commented Dr. John Krystal, Editor of Biological Psychiatry. “Perhaps the structural abnormalities contribute to the risk for the relapse of depression among individuals whose brain circuit activity has responded to antidepressant medications.”
More research will be necessary to test the theories generated from the findings of this study.
Nerve Cells Can Work in Different Ways with Same Result
Epilepsy, irregular heartbeats and other conditions caused by malfunctions in the body’s nerve cells, also known as neurons, can be difficult to treat. The problem is that one medicine may help some patients but not others. Doctors’ ability to predict which drugs will work with individual patients may be influenced by recent University of Missouri research that found seemingly identical neurons can behave the same even though they are built differently under the surface.
“To paraphrase Leo Tolstoy, ‘every unhappy nervous system is unhappy in its own way,’ especially for individuals with epilepsy and other diseases,” said David Schulz, associate professor of biological sciences in MU’s College of Arts and Science. “Our study suggests that each patient’s neurons may be altered in different ways, although the resulting disease is the same. This could be a major reason why doctors have difficulty predicting which medicines will be effective with specific individuals. The same problem could affect treatment of heart arrhythmia, depression and many other neurological conditions.”
It turns out, even happy neurons may be happy in their own way. Neurons have a natural electric activity that they are biologically programmed to maintain. If a neuron isn’t in that preferred state, the cell tries to restore it. However, contrary to some previous beliefs about neuron functioning, Schulz’s research found that two essentially identical neurons can reach the same preferred electrical activity in different ways.
In Schulz’s study, individual neurons used different combinations of cellular pores, known as ion channels, to achieve the same end goal of their preferred electrical and chemical balances. Schulz compared the situation to five people in separate rooms being given sets of blocks and told to construct a tower. Each person could devise a different method for constructing the same structure.
Schulz’s finding could inform doctor’s treatment of epilepsy. In epileptics, the neurons of the brain frequently receive too little stimulation from other neurons. Those under-stimulated epileptic neurons may overcompensate and become too sensitive. Then, when any impulses actually do reach them from other neurons, those hyper-sensitive epileptic neurons may over-react and cause a seizure.
Schulz worked with Satish Nair, professor of electrical and computer engineering in MU’s College of Engineering. The collaboration allowed their team to model nerve cell behavior in computer simulations in addition to his physical experiments using crab nervous systems.
The study, “Neurons with the same network independently achieve conserved output by differentially balancing variable conductance magnitudes,” was published in the Journal of Neuroscience. Joseph L. Ransdell, an MU doctoral student was the lead researcher of the study.
Brain differences seen in depressed preschoolers
A key brain structure that regulates emotions works differently in preschoolers with depression compared with their healthy peers, according to new research at Washington University School of Medicine in St. Louis.
The differences, measured using functional magnetic resonance imaging (fMRI), provide the earliest evidence yet of changes in brain function in young children with depression. The researchers say the findings could lead to ways to identify and treat depressed children earlier in the course of the illness, potentially preventing problems later in life.
“The findings really hammer home that these kids are suffering from a very real disorder that requires treatment,” said lead author Michael S. Gaffrey, PhD. “We believe this study demonstrates that there are differences in the brains of these very young children and that they may mark the beginnings of a lifelong problem.”
The study is published in the July issue of the Journal of the American Academy of Child & Adolescent Psychiatry.
Depressed preschoolers had elevated activity in the brain’s amygdala, an almond-shaped set of neurons important in processing emotions. Earlier imaging studies identified similar changes in the amygdala region in adults, adolescents and older children with depression, but none had looked at preschoolers with depression.
For the new study, scientists from Washington University’s Early Emotional Development Program studied 54 children ages 4 to 6. Before the study began, 23 of those kids had been diagnosed with depression. The other 31 had not. None of the children in the study had taken antidepressant medication.
Although studies using fMRI to measure brain activity by monitoring blood flow have been used for years, this is the first time that such scans have been attempted in children this young with depression. Movements as small as a few millimeters can ruin fMRI data, so Gaffrey and his colleagues had the children participate in mock scans first. After practicing, the children in this study moved less than a millimeter on average during their actual scans.
While they were in the fMRI scanner during the study, the children looked at pictures of people whose facial expressions conveyed particular emotions. There were faces with happy, sad, fearful and neutral expressions.
“The amygdala region showed elevated activity when the depressed children viewed pictures of people’s faces,” said Gaffrey, an assistant professor of psychiatry. “We saw the same elevated activity, regardless of the type of faces the children were shown. So it wasn’t that they reacted only to sad faces or to happy faces, but every face they saw aroused activity in the amygdala.”
Looking at pictures of faces often is used in studies of adults and older children with depression to measure activity in the amygdala. But the observations in the depressed preschoolers were somewhat different than those previously seen in adults, where typically the amygdala responds more to negative expressions of emotion, such as sad or fearful faces, than to faces expressing happiness or no emotion.
In the preschoolers with depression, all facial expressions were associated with greater amygdala activity when compared with their healthy peers.
Gaffrey said it’s possible depression affects the amygdala mainly by exaggerating what, in other children, is a normal amygdala response to both positive and negative facial expressions of emotion. But more research will be needed to prove that. He does believe, however, that the amygdala’s reaction to people’s faces can be seen in a larger context.
“Not only did we find elevated amygdala activity during face viewing in children with depression, but that greater activity in the amygdala also was associated with parents reporting more sadness and emotion regulation difficulties in their children,” Gaffrey said. “Taken together, that suggests we may be seeing an exaggeration of a normal developmental response in the brain and that, hopefully, with proper prevention or treatment, we may be able to get these kids back on track.”
(Source: news.wustl.edu)
Helping SAD Sufferers Sleep Soundly
Lying awake in bed plagues everyone occasionally, but for those with seasonal affective disorder, sleeplessness is routine.University of Pittsburgh researchers report in the Journal of Affective Disorders that individuals with seasonal affective disorder (SAD)—a winter depression that leads to loss of motivation and interest in daily activities—have misconceptions about their sleep habits similar to those of insomniacs. These findings open the door for treating seasonal affective disorder similar to the way doctors treat insomnia.
Kathryn Roecklein, primary investigator and assistant professor in Pitt’s Department of Psychology within the Kenneth P. Dietrich School of Arts and Sciences, along with a team of researchers from Pitt’s School of Medicine and Reyerson University, investigated why, according to a previously published sleep study by the University of California, Berkeley, individuals with seasonal affective disorder incorrectly reported that they slept four more hours a night in the winter.
“We wondered if this misreporting was a result of depression symptoms like fatigue and low motivation, prompting people to spend more time in bed,” said Roecklein. “And people with seasonal affective disorder have depression approximately five months a year, most years. This puts a significant strain on a person’s work life and home life.”
Roecklein and her team interviewed 147 adults between the ages of 18 and 65 living in the Pittsburgh metropolitan area during the winters of 2011 and 2012. Data was collected through self-reported questionnaires and structured clinical interviews in which participants were asked such questions as: “In the past month, have you been sleeping more than usual?” and “How many hours, on average, have you been sleeping in the past month? How does that compare to your normal sleep duration during the summer?”
In order to understand participants’ ideas about sleep, Roecklein’s team asked them to respond to questions such as “I need at least 8 hours of sleep to function the next day” and “Insomnia is dangerous for health” on a scale from 0 to 7, where 7 means “strongly agree” and 0 means “disagree completely.”
Roecklein and her team found that SAD participants’ misconceptions about sleep were similar to the “unhelpful beliefs” or personal misconceptions about sleep that insomniacs often hold. Due to depression, individuals with SAD, like those with insomnia, may spend more time resting in bed, but not actually sleeping—leading to misconceptions about how much they sleep. These misconceptions, said Roecklein, play a significant role in sleep cognition for those with seasonal affective disorder.
“We predict that about 750,000 people in the Pittsburgh metro area suffer from seasonal affective disorder, making this an important issue for our community and the economic strength and vitality of our city,” said Roecklein. “If we can properly treat this disorder, we can significantly lower the number of sufferers in our city.”
Roecklein’s research data suggests that addressing, understanding, and managing these “unhelpful beliefs” about sleep by way of psychotherapy could lead to improved treatments for seasonal affective disorder. One of the most effective treatment options for insomnia, said Roecklein, is cognitive behavioral therapy for insomnia (known as CBT-I), which aims to help people take control of their thinking to improve their sleep habits as well as mood, behavior, and emotions.
Roecklein’s next research project aims to improve treatment for seasonal affective disorder by studying light perception and biological clock synchronization. Light from the environment synchronizes internal biological rhythms with the timing of dawn and dusk, which naturally changes with the seasons. This synchronization allows people to be awake and alert during the day and to sleep at night. Roecklein will examine whether people with seasonal affective disorder perceive this light from the environment differently because of changes in the function of neurological pathways from the eye to the brain. This could help uncover reasons why people suffer from seasonal affective disorder and could suggest new treatment options.
(Image: Shutterstock)