Considering sex differences in death by suicide

by Michael D. Anestis, Ph.D.

Came across a very interesting study in the Journal of Affective Disorders by Anna Cibis and her colleagues (2012).  In this paper, the authors attempted to look more closely at sex differences in suicidal behavior and to further open the discussion about why the trends are what they are.  Some basic background facts:

• Women attempt suicide at a substantially higher rate than do men
• Men die by suicide at a substantially higher rate than do women (China is the only consistent exception to that rule)
• In the US, more than 50% of deaths by suicide are due to self-inflicted gunshot wounds, with approximately 67% of male suicide deaths accounted for by this method and 33% of female deaths by suicide accounted for by this method (intentional overdose is the most common method for women)
• Click here for a summary of these and other stats

Looking at these numbers, many people assume that the reason that more men die by suicide despite the fact that more women attempt suicide is that men choose more lethal means.  Dr.Cibis and her colleagues (2012) decided to look more closely at this possibility.  Using data from Nuremberg and Wuerzburg between the years of 2000 and 2004, the authors looked at the number of suicide attempts and deaths overall and by method across sex.  Overall, their sample included 2579 non-lethal suicide attempts and 656 deaths by suicide.  As expected, women were more likely to attempt but men were more likely to die by suicide in their sample.

Some notable numbers:

• The most lethal means used was hanging (77% attempts resulted in death)
• The least lethal means used was poisoning by drugs (4.7% attempts resulted in death)
• The most common attempt method in non-lethal attempts was poisoning by drugs (67.7% of non-lethal attempts)
• The least common attempt method in non-lethal attempts was firearms (0.6% of non-lethal attempts)
• The most common attempt method in lethal attempts was hanging (39.5% of lethal attempts)
• The least common attempt method in lethal attempts was "other methods" (2.6% of lethal attempts)

The authors noted that the overall case fatality for men (32.5%) was siginficantly higher than it was in women (10.1%).  More interestingly however, the fatality rate in women was lower in every method except for drowning and the difference was statistically signficant in five methods: hanging, poisoning by drugs, poisoning by other means, using sharp objects, and moving objects.  This last point gets to the issue raised at the beginning of this post.  If sex differences in death by suicide are accounted for purely by choice of method, there should be differences in which methods men and women choose, but there should not be differences in the rate at which each method is lethal.

The authors conclude that this study points to the need to consider issues beyond selection of means and I think that is more than legitimate.  That being said, it is also important to note a couple issues.  First, there was no measurement of difference in the manner in which each method was used (e.g., type and amount of drugs used in intentional overdose, height of fatal/nonfatal jumps, efforts to abort attempt once started).  Second, only 8.1% of suicide deaths were accounted for by firearms.  That being said, firearms are not the most common method used in fatal attempts across countries but they are in the US, so this difference makes it difficult to know to what degree these results would generalize to the US, where attempt methods appear to differ quite a bit from this sample.

So...what do you think accounts for these differences?  I think there are a number of options, but the one that jumps out to me the most is the acquired capability for suicide.  I can't help but wonder if levels of the acquired capability would statstically account for the sex differences across methods (and overall).

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Dr. Anestis is a post-doctoral fellow with the Military Suicide Research Consortium

Articles cited in this post

Cibis, A., Mergl, R., Bramesfeld, A., Althaus, D., Niklewski, G., Schmidtke, A., & Hergerl, U. (2012).  Preference of lethal methods is not the only cause for higher suicide rates in males.  Journal of Affective Disorders, 136, 9-16.