Thursday, April 20, 2017

'Tis The Season - Seasonality and Suicide

From reference 1 - see for details. 

My first job as a staff psychiatrist was in a clinic in Superior, Wisconsin just across the harbor from Duluth, Minnesota where I lived.  For two of the years I worked there, a local television station would interview me about depression, suicide, and Christmas - at least that was their take on the story.  What would be better drama than a tumultuous family gathering, heated arguments, disappointment, and increasing depression?  That would be a great dramatic story if it was true, but it is not.  For two years, I battled with the reporters to tell the real story about seasonality and suicide, but in the end I lost.  Prior to the last interview, I went as far as saying: "Look - don't make the connection between Christmas and depression or suicide.  It really does not exist."  The first question I was asked: "Isn't it true that depression peaks at Christmas time?  Can you suggest a few reasons why that occurs?"   I fumbled along trying my best to explain what really happens.  All of these interviews are heavily edited down to a couple of sound bites.  The final version really did not have much to say about anything.

In the intervening 30 years, I have had a lot of time to think about the problem.  As a clinical psychiatrist one of the most frequent problems I encounter is suicide prevention.  Seasonality and suicide is never really mentioned very much in modern day suicide assessment or treatment.  The popular screening checklists don't have anything to say about seasons.  I have no doubt that clinically - suicidal thinking and suicide attempts correlate well with what is written in the literature.  The literature says that late spring is the peak season for suicides and that is what I have observed directly over 30 years of experience.  The main question is how this is relevant to the treatment and prevention of suicidal thinking and behavior.

In the referenced review, the authors do a reasonable job of summarizing what is known about the association of various environmental factors and suicide.  Studies of rare events are always affected by the ecological fallacy of inferring the behavior of individuals from membership in large groups.  We end up with extremely small numerators of people who have completed suicide relative to their membership in rather massive groups - like all Spring allergy suffers or in the case of biological psychiatrists the even larger group of everyone with seasonally low tryptophan levels.  The authors description of the effect of seasons on tryptophan levels and serotonin turnover is interesting but I disagree with their conclusion.  I do not think that much higher levels of serotonin turnover in bright sunlight negate tryptophan levels as an arbiter of suicidal behavior in the late spring.

We are currently approaching the end of April in southern Minnesota.  That last two days have been bitterly cold and wet.  Everybody is talking about how gloomy and depressing the weather is.  At this point in time, practically every friend, family member, and patient I have seen has had at least two upper respiratory tract infections (URI) of varying severity.  These viruses are generally flu-like illnesses (FLI) in that they produce all of the same symptoms except high fevers and can last up to 2 1/2 weeks.  In April and May, the population is in survival mode and we are looking for a break.  It doesn't necessarily have to be better weather, but that is the only practical way to be rid of the pestilence that is associated with winter.  The authors in the review look at cytokine and immune modulated mechanisms but they are highly speculative.  Not enough is known about the specific environment that suicidal people have experienced.  In the USA for example, not everybody at a certain latitude will see reduced sunlight and epidemic exposure to URIs.  At some point technology may allow widespread sampling and reconstruction of the true environment.  In the mean time studying specific work or school environments may be a more productive research approach.  

Seeing patients who tell me that they are getting more depressed and experiencing suicidal thoughts this time of the year makes me more vigilant.  After seeing most patients with these problems, I run the conversation back in my head a few more times than usual.  I am trying to see if I may have missed anything.  It is my version of the preemptive psychological autopsy - to prevent the necessity of a real one.  Psychotic depression can be very subtle and  people with that particular problem can be difficult to establish a working alliance with.  They may also have suicide attempts by highly lethal means.  The most important part of the conversation is giving them hope and having a plan to access emergency services.  But even before that I caution them that the progression to a state where they consider suicide is a sequence of events that needs to be recognized and interrupted at the earliest possible point.  All of that discussion is necessary in addition to pharmacotherapy.  One of the most important aspects of any mental health crisis is recognizing that you will be coming through on the other side.

That is as true about Spring as it is for anything else.

George Dawson, MD, DFAPA


1:  Woo J-M, Okusaga O, Postolache TT. Seasonality of Suicidal Behavior. International Journal of Environmental Research and Public Health. 2012;9(2):531-547. doi:10.3390/ijerph9020531.

Figure at the top of this page is from reference 1 - an open access article. Reprinted here per
Creative Commons Attribution 3.0 Unported (CC BY 3.0) license. Original graph is unaltered.

2:  Hankoff LD. Suicide and attempted suicide. in Handbook of Affective of Disorders. Eugene S. Paykel (ed). The Guilford Press. New York. 1982 pages 417-428.

"Durkheim's study of the seasonality of suicide helped to confirm his impression of social factors on suicide.  ..... From the months of January through June there was a progressive increase in the rate of suicide and from June onward a progressive decrease."  p. 418

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