FYI: Suicide behavior is a disease

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Suicidal behaviour is a disease, psychiatrists argue

As suicide rates climb steeply in the US a growing number of psychiatrists are arguing that suicidal behaviour should be considered as a disease in its own right, rather than as a behaviour resulting from a mood disorder.

They base their argument on mounting evidence showing that the brains of people who have committed suicide have striking similarities, quite distinct from what is seen in the brains of people who have similar mood disorders but who died of natural causes.

Suicide also tends to be more common in some families, suggesting there may be genetic and other biological factors in play. What’s more, most people with mood disorders never attempt to kill themselves, and about 10 per cent of suicides have no history of mental disease.

The idea of classifying suicidal tendencies as a disease is being taken seriously. The team behind the fifth edition of the Diagnostic Standards Manual (DSM-5) – the newest version of psychiatry’s “bible”, released at the American Psychiatric Association’s meeting in San Francisco this week – considered a proposal to have “suicide behaviour disorder” listed as a distinct diagnosis. It was ultimately put on probation: put into a list of topics deemed to require further research for possible inclusion in future DSM revisions.

Another argument for linking suicidal people together under a single diagnosis is that it could spur research into the neurological and genetic factors they have in common. This could allow psychiatrists to better predict someone’s suicide risk, and even lead to treatments that stop suicidal feelings.

Signs in the brain

Until the 1980s, the accepted view in psychiatry was that people who committed suicide were, by definition, depressed. But that view began to change when autopsies revealed distinctive features in the brains of people who had committed suicide, including structural changes in the prefrontal cortex – which controls high-level decision-making – and altered levels of the neurochemical serotonin. These characteristics appeared regardless of whether the people had suffered from depression, schizophrenia, bipolar disorder, or no disorder at all (Brain Researchdoi.org/cvrpjk).

But there is no single neurological cause of suicide, says Gustavo Turecki of McGill University in Montreal. What is more likely, he says, is that environmental factors trigger a series of changes in the brains of people who are already genetically prone to suicide, contributing to a constellation of factors that ultimately increase risk. These factors include a history of abuse as a child, post-traumatic stress disorder, long periods of anxiety, or sleep deprivation.

The search for more of these factors is complicated by the rarity of brain samples from suicide victims and the lack of an animal model – humans are unique in their wilful ability to end their lives. But some studies are yielding insights. For example, when people with bipolar disorder who have previously attempted suicide begin taking lithium, they tend to stop attempting suicide even if the drug has no effect on their other symptoms. This suggests that the drug may be acting on neural pathways that specifically influence suicidal tendencies (Annual Review of Pharmacology and Toxicologydoi.org/dfjv57) .

In the genes?

There is also growing evidence that genetics plays a role. For example, according to one study, identical twins share suicidal tendencies 15 per cent of the time, compared with 1 per cent in non-identical twins (Journal of Affective Disordersdoi.org/d23nvw). And a study of adopted people who had committed suicide found that their biological relatives were six times more likely to commit suicide than members of the family that adopted them (American Journal of Medical Geneticsdoi.org/fmsncv).

A number of individual genes have been linked to suicide, such as those involved in the brain’s response to mood-lifting serotonin, and a signalling molecule called brain-derived neurotrophic factor (BDNF), which regulates the brain’s response to stress. Both tend to be suppressed in the brains of people who committed suicide, regardless of what mental disorder they had. Other studies of post-mortem brains have found that people who commit suicide after a bout of depression have different brain chemistry from depressed people who die of natural causes.

A study by Turecki, published this month, compared the brains of 46 people who had committed suicide with those of 16 people who died of natural causes. In the first group, 366 genes, mostly related to learning and memory, had a different set of epigenetic markers – chemical switches that turn genes on and off (American Journal of Psychiatrydoi.org/mf7). The results are complicated by the fact that many of the people who committed suicide suffered from mental disorders, but Turecki says that suicide, rather than having a mental disorder, was the only significant predictor for these specific epigenetic changes.

No one yet knows the mechanism through which environmental factors would alter these genes, although stress hormones such as cortisol may be playing a role.

Understanding risk

Ultimately, biological and genetic markers might allow psychiatrists to better predict which patients are most at risk of suicide. But David Brent of the University of Pittsburgh, Pennsylvania, cautions that even if we can one day use biomarkers to predict if someone will make a suicide attempt, they do not tell us when. “If clinicians are keeping an eye on a patient, they need to know if there’s imminent risk,” he says.

However, knowing someone’s long-term suicide risk may have important implications for how a doctor chooses to treat that person, says Jan Fawcettof the University of New Mexico in Albuquerque.

For instance, a doctor may decide not to prescribe certain antidepressants to a patient with these biomarkers, as many drugs are thought to increase suicide risk. Another question would be whether to commit a person to a mental hospital – a major decision, he says, as people are most likely to commit suicide right after being released from hospital (Archives of General Psychiatrydoi.org/d669kx).

David Shaffer of Columbia University in New York, who was a member of theDSM-V working group, says that suicide behaviour disorder is “very much in the spirit” of the new Research Domain Criteria system that the US National Institute of Mental Health proposed as an alternative diagnosis standard to DSM-V. Rather than diagnosing people with depression or bipolar disorder, for example, the NIMH wants mental disorders to be diagnosed and treated more objectively using patients’ behaviour, genetics and neurobiology.

Ultimately, says Nader Perroud of the University of Geneva in Switzerland, if suicidal behaviour is considered as a disease in its own right, it will become possible to conduct more focused, evidence-based research on it and medications that treat it effectively. “We might be able to find a proper treatment for suicidal behaviour.”

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4 thoughts on “FYI: Suicide behavior is a disease

  1. Fascinating! In regard to the article stating, that being committed increases suicide risk immediately afterward…I wonder what option doctors really have, if a patient is a danger to self, or others–being primarily a genetically induced illness, as explained.

    I like the idea proposed–of broader categories and symptom clustering for diagnosing illness–instead of just a narrowly confined label…Good article!

  2. You hear of it all the time, about people being released from the hospital only to die by their own hands. Supervision is key. If you recall, that is what happened to Soos (FMO) not long after she was released in July (the first attempt)…she died Aug 12th. It is a tenuous situation when the brain is involved, thoughts, decisions, impulse, etc…. I don’t know that the answer would be in regard to options. Thank you for reading. xo

  3. Wow…this is fascinating research. I got my bachelor’s in psychology, and–if I’d known about this research before I’d done my senior thesis–THIS is what it would’ve been on.

    As for suicidal ideation–the “idea” of committing suicide need not necessarily coincide with the “act” of doing it. I’ve heard stories of people who you’d never expect end their lives seemingly “out of the blue.” Yet, I’ve known people personally who have (like myself) thought about it for years, and never followed through with it.

    I’d like to think I never will, and haven’t contemplated it seriously for years.

    From a psychological perspective, something that needs to be involved in these studies is the age factor–teenagers and people up to age 25 are much more likely to commit suicide than someone who is in the 35-45 year old age range. However, people in their mid-sixties are also more prone. So, statstically, there is a margin for young people, and older people (up to a certain point–I think age 70-75, and then the behavioral statistic dwindles again).

    In regard to the study–is there a difference neurologically in the age gaps? It seems almost obvious that these are two different groups of people, with completely different behavioral patterns leading into suicide. But I may be wrong.

    As for insomnia-related suicidal behavior: as an insomniac, I can tell you–YES, not being able to sleep for more than an hour or two a night for months on end WILL drive you to consider it. I don’t know what I’d do without my sleep meds.

    I’d like to keep an eye on this area of research and see where it goes.

    • Thank you, Derek, for your thoughtful comment. I would not know any of this information on suicide had it not been for the personal loss of my son. Desperately, I have wondered and searched for the answers. It seems that there is not just one reason but several and those may or may not apply to every single suicide. I have set goals to eliminate the unfair stigma that has followed those who have “suicided” and those who have loved and lost those dear to them through this complex way of dying. Blogging is therapeutic for me but my intention is to find out all that I can to bring peace of mind to others and also to myself. Too many times I have heard people (internet folk) who are so very wrong about the whys and wherefores of suicide, blaming a flawed character or abusive parents….just to name a couple. I take special offense to the abusive parents label because my son was loved very much and he knew this. He “had everything” except a loving wife. Aha….and therein lies some of the problem…just one. With the biological factor being a key to the actual suicide of a person, the rest is just the “one or more thing (s)” that can be the catalyst for completing the act.

      I hope you continue to read and gather as much information as you can on this subject. It will take many more blogs, research, and education to help educate the public about the causes and the effects on those who are left.

      At a glance (your profile pic), you remind me of Brandon. He was serious and intense about life…and he was so very talented and creative….very smart, too. I wish you all the best.

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