Posts tagged suicidal behavior
Articles and news from the latest research reports.
Association between sunshine and suicide examined in study
Lower rates of suicide are associated with more daily sunshine in the prior 14 to 60 days.
Light interacts with brain serotonin systems and possibly influences serotonin-related behaviors. Those behaviors, such as mood and impulsiveness, can play a role in suicide.
The authors examined the relationship between suicide and the duration of sunshine after mathematically removing seasonal variations in sunshine and suicide numbers. They analyzed data on 69,462 officially confirmed suicides in Austria between January 1970 and May 2010. Hours of sunshine per day were calculated from 86 representative meteorological stations.
There was a positive correlation between the number of suicides and hours of daily sunshine on the day of the suicide and up to 10 days before that seemed to facilitate suicide, while sunshine 14 to 60 days prior appeared to have a negative correlation and was associated with reduced suicides. The correlation between daily sunshine hours and suicide rates was seen largely among women, while negative correlations between the two were mainly found among men.
"Owing to the correlative nature of the data, it is impossible to directly attribute the increase in suicide to sunshine during the 10 days prior to the suicide event. … Further research is warranted to determine which patients with severe episodes of depression are more susceptible to the suicide-triggering effects of sunshine."
(Image: Shutterstock)
A blood test for suicide?
Johns Hopkins researchers say they have discovered a chemical alteration in a single human gene linked to stress reactions that, if confirmed in larger studies, could give doctors a simple blood test to reliably predict a person’s risk of attempting suicide.
The discovery, described online in The American Journal of Psychiatry, suggests that changes in a gene involved in the function of the brain’s response to stress hormones plays a significant role in turning what might otherwise be an unremarkable reaction to the strain of everyday life into suicidal thoughts and behaviors.
“Suicide is a major preventable public health problem, but we have been stymied in our prevention efforts because we have no consistent way to predict those who are at increased risk of killing themselves,” says study leader Zachary Kaminsky, Ph.D., an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine. “With a test like ours, we may be able to stem suicide rates by identifying those people and intervening early enough to head off a catastrophe.”
For his series of experiments, Kaminsky and his colleagues focused on a genetic mutation in a gene known as SKA2. By looking at brain samples from mentally ill and healthy people, the researchers found that in samples from people who had died by suicide, levels of SKA2 were significantly reduced.
Within this common mutation, they then found in some subjects an epigenetic modification that altered the way the SKA2 gene functioned without changing the gene’s underlying DNA sequence. The modification added chemicals called methyl groups to the gene. Higher levels of methylation were then found in the same study subjects who had killed themselves. The higher levels of methylation among suicide decedents were then replicated in two independent brain cohorts.
In another part of the study, the researchers tested three different sets of blood samples, the largest one involving 325 participants in the Johns Hopkins Center for Prevention Research Study found similar methylation increases at SKA2 in individuals with suicidal thoughts or attempts. They then designed a model analysis that predicted which of the participants were experiencing suicidal thoughts or had attempted suicide with 80 percent certainty. Those with more severe risk of suicide were predicted with 90 percent accuracy. In the youngest data set, they were able to identify with 96 percent accuracy whether or not a participant had attempted suicide, based on blood test results.
The SKA2 gene is expressed in the prefrontal cortex of the brain, which is involved in inhibiting negative thoughts and controlling impulsive behavior. SKA2 is specifically responsible for chaperoning stress hormone receptors into cells’ nuclei so they can do their job. If there isn’t enough SKA2, or it is altered in some way, the stress hormone receptor is unable to suppress the release of cortisol throughout the brain. Previous research has shown that such cortisol release is abnormal in people who attempt or die by suicide.
Kaminsky says a test based on these findings might best be used to predict future suicide attempts in those who are ill, to restrict lethal means or methods among those a risk, or to make decisions regarding the intensity of intervention approaches.
He says that it might make sense for use in the military to test whether members have the gene mutation that makes them more vulnerable. Those at risk could be more closely monitored when they returned home after deployment. A test could also be useful in a psychiatric emergency room, he says, as part of a suicide risk assessment when doctors try to assess level of suicide risk.
The test could be used in all sorts of safety assessment decisions like the need for hospitalization and closeness of monitoring. Kaminsky says another possible use that needs more study could be to inform treatment decisions, such as whether or not to give certain medications that have been linked with suicidal thoughts.
“We have found a gene that we think could be really important for consistently identifying a range of behaviors from suicidal thoughts to attempts to completions,” Kaminsky says. “We need to study this in a larger sample but we believe that we might be able to monitor the blood to identify those at risk of suicide.”
(Source: hopkinsmedicine.org)
Repeat Brain Injury Raises Soldiers’ Suicide Risk
People in the military who suffer more than one mild traumatic brain injury face a significantly higher risk of suicide, according to research by the National Center for Veterans Studies at the University of Utah.
A survey of 161 military personnel who were stationed in Iraq and evaluated for a possible traumatic brain injury – also known as TBI – showed that the risk for suicidal thoughts or behaviors increased not only in the short term, as measured during the past 12 months, but during the individual’s lifetime.
The risk of suicidal thoughts increased significantly with the number of TBIs, even when controlling for other psychological factors, the researchers say in a paper published online Wednesday, May 15 in JAMA Psychiatry, a specialty journal of the American Medical Association.
“Up to now, no one has been able to say if multiple TBIs, which are common among combat veterans, are associated with higher suicide risk or not,” says the study’s lead author, Craig J. Bryan, assistant professor of psychology at the University of Utah and associate director of the National Center for Veterans Studies. “This study suggests they are, and it provides valuable information for professionals treating wounded combat servicemen and women to help manage the risk of suicide.”
Results showed that one in five patients (21.7 percent) who had ever sustained more than one TBI reported suicidal ideation – thoughts about or preoccupation with suicide – at any time in the past. For patients who had received one TBI, 6.9 percent reported having suicidal thoughts, and zero percent for those with no TBIs. In evaluating the lifetime risk, patients were asked if they had ever experienced suicidal thoughts and behaviors up to the point they were assessed.
The increases were similar for suicidal thoughts during the previous year rather than at any time: 12 percent of those with multiple TBIs had entertained suicidal ideas during the past year, compared with 3.4 percent with one TBI and zero percent for no TBIs.
In this study, suicidal ideation was used as the indicator of suicide risk because too few patients reported a history of suicide plan or had made a suicide attempt for statistically valid conclusions to be made.
Researchers found that multiple TBIs also were associated with a significant increase in other psychological symptoms already tied to single traumatic head injuries, including depression, post-traumatic stress disorder or PTSD, and the severity of the concussive symptoms. However, only the increase in depression severity predicted an increased suicide risk.
“That head injury and resulting psychological effects increase the risk of suicide is not new,” says Bryan. “But knowing that repetitive TBIs may make patients even more vulnerable provides new insight for attending to military personnel over the long-term, particularly when they are experiencing added emotional distress in their lives.”
How the Study was Conducted
During a six-month period in 2009, 161 patients who received a suspected brain injury while on duty in Iraq were referred to an outpatient TBI clinic at a combat support hospital there. Patients were predominantly male, average age of 27, with 6.5 years of military service.
Diagnosis of traumatic brain injury was made by a clinical psychologist specifically trained in the assessment, diagnosis and management of the condition. Only patients with mild or no TBI completed all assessments; patients with moderate to severe TBI were immediately evacuated from Iraq.
TBI was confirmed if at least one clinical event was newly presented or worsened following the injury: loss of consciousness or memory, alteration of mental state, some neurological decline or brain damage.
Patients were divided into three groups based the total number of TBIs during their entire lives – zero, single TBI and two or more – the most recent of which was typically within the days immediately preceding their evaluation and inclusion in the study.
Each individual was also given surveys as part of his or her evaluation and treatment. Using standard evaluation tools, patients were surveyed about their symptoms of depression, PTSD and concussions, and their suicidal thoughts and behaviors.
“An important feature of the study is that by being on the ground in Iraq, we were able to compile a unique data set on active military personnel and head injury,” Bryan says. “We collected data on a large number of service members within two days of impact.”
At the same time, because the results of this study are based on a single clinical sample –active military in a war zone within days of the injury – the researchers note that caution is advised before assuming that the results from this particular group will apply to every other group. Studies with larger sample sizes and conducted over longer periods of time will be needed.
Why TBI is of Concern for Military Personnel
As defined by the Centers for Disease Control and Prevention, a traumatic brain injury is caused by a bump, blow or jolt to the head, or a penetrating head injury that disrupts the normal function of the brain. Effects can be mild to severe. The majority of TBIs that occur each year are concussions or other mild forms.
TBI is considered a “signature injury” of the Iraq and Afghanistan conflicts and is of particular concern because of the frequency of concussive injuries from explosions and other combat-related incidents. Estimated prevalence of TBI for those deployed in these two countries ranges from 8 percent to 20 percent, according to a 2008 study.
In addition, according to studies by the RAND Corp., suicide is the second-leading cause of death among U.S. military personnel, and the rate has risen steadily since the conflicts began in Iraq and Afghanistan. Prevalence of PTSD, depression and substance abuse have risen as well, especially among those in combat, and each has been shown to increase risk for suicidal behaviors.
“Being aware of the number of a patient’s head injuries and the interrelation with depression and other psychological symptoms may help us better understand, and thus moderate, the risk of suicide over time,” Bryan says. “Ultimately, we would like to know why people do not kill themselves. Despite facing similar issues and circumstances, some people recover. Understanding that is the real goal.”
Countering brain chemical could prevent suicides
Researchers have found the first proof that a chemical in the brain called glutamate is linked to suicidal behavior, offering new hope for efforts to prevent people from taking their own lives.
Writing in the journal Neuropsychopharmacology, Michigan State University’s Lena Brundin and an international team of co-investigators present the first evidence that glutamate is more active in the brains of people who attempt suicide. Glutamate is an amino acid that sends signals between nerve cells and has long been a suspect in the search for chemical causes of depression.
“The findings are important because they show a mechanism of disease in patients,” said Brundin, associate professor of translational science and molecular medicine in MSU’s College of Human Medicine. “There’s been a lot of focus on another neurotransmitter called serotonin for about 40 years now. The conclusion from our paper is that we need to turn some of that focus to glutamate.”
Brundin and colleagues examined glutamate activity by measuring quinolinic acid – which flips a chemical switch that makes glutamate send more signals to nearby cells – in the spinal fluid of 100 patients in Sweden. About two-thirds of the participants were admitted to a hospital after attempting suicide and the rest were healthy.
They found that suicide attempters had more than twice as much quinolinic acid in their spinal fluid as the healthy people, which indicated increased glutamate signaling between nerve cells. Those who reported the strongest desire to kill themselves also had the highest levels of the acid.
The results also showed decreased quinolinic acid levels among a subset of patients who came back six months later, when their suicidal behavior had ended.
The findings explain why earlier research has pointed to inflammation in the brain as a risk factor for suicide. The body produces quinolinic acid as part of the immune response that creates inflammation.
Brundin said anti-glutamate drugs are still in development, but could soon offer a promising tool for preventing suicide. In fact, recent clinical studies have shown the anesthetic ketamine – which inhibits glutamate signaling – to be extremely effective in fighting depression, though its side effects prevent it from being used widely today.
In the meantime, Brundin said physicians should be aware of inflammation as a likely trigger for suicidal behavior. She is partnering with doctors in Grand Rapids, Mich., to design clinical trials using anti-inflammatory drugs.
“In the future, it’s likely that blood samples from suicidal and depressive patients will be screened for inflammation,” Brundin said. “It is important that primary health care physicians and psychiatrists work closely together on this.”
Common Parasite May Trigger Suicide Attempts
August 16th, 2012
A parasite thought to be harmless and found in many people may actually be causing subtle changes in the brain, leading to suicide attempts.
New research appearing in the August issue of The Journal of Clinical Psychiatry adds to the growing work linking an infection caused by the Toxoplasma gondii parasite to suicide attempts. Michigan State University’s Lena Brundin was one of the lead researchers on the team.
About 10-20 percent of people in the United States have Toxoplasma gondii, or T. gondii, in their bodies, but in most it was thought to lie dormant, said Brundin, an associate professor of experimental psychiatry in MSU’s College of Human Medicine. In fact, it appears the parasite can cause inflammation over time, which produces harmful metabolites that can damage brain cells.
“Previous research has found signs of inflammation in the brains of suicide victims and people battling depression, and there also are previous reports linking Toxoplasma gondii to suicide attempts,” she said. “In our study we found that if you are positive for the parasite, you are seven times more likely to attempt suicide.”
The work by Brundin and colleagues is the first to measure scores on a suicide assessment scale from people infected with the parasite, some of whom had attempted suicide.
The Toxoplasma gondii parasite has been linked to inflammation in the brain, damaging cells. Image adapted from MSU press release image.
The results found those infected with T. gondii scored significantly higher on the scale, indicative of a more severe disease and greater risk for future suicide attempts. However, Brundin stresses the majority of those infected with the parasite will not attempt suicide: “Some individuals may for some reason be more susceptible to develop symptoms,” she said.
“Suicide is major health problem,” said Brundin, noting the 36,909 deaths in 2009 in America, or one every 14 minutes. “It is estimated 90 percent of people who attempt suicide have a diagnosed psychiatric disorder. If we could identify those people infected with this parasite, it could help us predict who is at a higher risk.”
T. gondii is a parasite found in cells that reproduces in its primary host, any member of the cat family. It is transmitted to humans primarily through ingesting water and food contaminated with the eggs of the parasite, or, since the parasite can be present in other mammals as well, through consuming undercooked raw meat or food.
Brundin has been looking at the link between depression and inflammation in the brain for a decade, beginning with work she did on Parkinson’s disease. Typically, a class of antidepressants called selective serotonin re-uptake inhibitors, or SSRIs, have been the preferred treatment for depression. SSRIs are believed to increase the level of a neurotransmitter called serotonin but are effective in only about half of depressed patients.
Brundin’s research indicates a reduction in the brain’s serotonin might be a symptom rather than the root cause of depression. Inflammation, possibly from an infection or a parasite, likely causes changes in the brain’s chemistry, leading to depression and, in some cases, thoughts of suicide, she said.
“I think it’s very positive that we are finding biological changes in suicidal patients,” she said. “It means we can develop new treatments to prevent suicides, and patients can feel hope that maybe we can help them.
“It’s a great opportunity to develop new treatments tailored at specific biological mechanisms.”
Source: Neuroscience News