Critique 166: The association between alcohol consumption and suicidal ideation and suicidal attempt — 1 July 2015

Bae H-C, Hong S, Jang S-I, Lee K-S, Park F-C.  Patterns of Alcohol Consumption and Suicidal Behavior: Findings From the Fourth and Fifth Korea National Health and Nutritional Examination Survey (2007–2011).  J Prev Med Public Health 2015;48:142-150 • http://dx.doi.org/10.3961/jpmph.14.027

Authors’ Abstract

Objectives: The purpose of this study was to investigate the association between suicidal behavior and patterns of alcohol consumption in Korean adults.

Methods: This study was based on data provided by the Korea National Health and Nutritional Examination Survey from 2007 to 2011. A total of 42 347 subjects were included in the study, of whom 19 292 were male and 23 055 were female. Logistic regression analysis was performed to assess the association between patterns of alcohol consumption and suicidal behavior.

Results: Among the study subjects, 1426 males (11.3%) and 3599 females (21.2%) had experienced suicidal ideation, and 106 males (0.8%) and 190 females (1.1%) had attempted suicide during the previous 12 months. Alcohol Use Disorders Identification Test (AUDIT) scores were found to be associated with suicidal ideation in males and associated with both suicidal ideation and suicide attempts in females. Alcoholic blackouts were associated with suicidal ideation and suicide attempts in males, and were also associated with suicidal ideation in females.

Conclusions: In this study, we found that certain patterns of alcohol consumption were associated with suicidal behaviors. In particular, only alcoholic blackouts and categorized AUDIT scores were found to be associated with suicidal behavior in males. We therefore suggest that Further research is needed to examine this relationship prospectively and in other settings.

Forum Comments

There has often been a discussion about the use of alcohol in conjunction with suicide, and subjects attempting suicide are often found to have been drinking heavily.  Further, depression often underlies attempts at suicide, and alcohol consumption can both add to the risk of depression or be used by some to alleviate depression.

The present study evaluates the relation between alcohol consumption and pattern of drinking with self-reports of suicidal ideation and suicidal attempts among men and women in Korea.  From data provided by the Korea National Health and Nutritional Examination Survey from 2007 to 2011 with more than 43,000 subjects, logistic regression analysis was performed to assess the association between patterns of alcohol consumption and suicidal behavior.

The key findings of the study reported by the authors are that 11.3% of males and 21.2% of females reported that they had experienced suicidal ideation, and 0.8% of males and 1.1% of females had attempted suicide.  Scores on the Alcohol Use Disorders Identification Test (AUDIT) and and a history of alcoholic blackouts were associated with suicidal ideation for males and females and with suicidal attempts among males.

Specific Comments on the study:  For all analyses, the data indicate that increased risk of suicidal tendencies are associated with heavier drinking, especially alcohol misuse (a high score on the AUDIT instrument) and “blacking out” from excessive alcohol.  The risk of suicidal ideation seems to rise at lower levels of alcohol intake among women (e.g., an increase in risk with an AUDIT score exceeding 8 for women, but only above 20 for men; also, an increase starts at 3-4 drinks/occasion for women and not even above 10 drinks/occasion for men).

The authors point out that “Among males, no significant associations were found between either drinking frequency or drinking quantity and suicidal behaviors,” suggesting that intoxication is more important that the number of drinks consumed.  For women, however (among whom the number of heavy drinkers was low), more frequent drinkers and those reporting more than 1 or 2 drinks per occasion had higher suicidal tendencies.  It should be noted, however, that the women in this cohort were primarily non-drinkers or very occasional drinkers: 92% of the women reported consuming alcohol only 2-4 times/month or less frequently, and less than 2% of women were in the highest drinking category of drinking ≥ 4 times/week.  Hence estimates of effect among women may be less reliable than those among men.

Overall, drinking alcohol according to the usual guidelines for “sensible drinking” did not increase the risk of suicidal ideation or attempt in this study.  For both men and women, there were no significant increases in risk for those reporting no more than 1 to 2 drinks/occasion.

The authors report that 9.4% of males and 17.6% of females reported a history of major depression during the previous year.  While their analyses adjusted for this, it is likely that these self-reports of depression did not fully adjust for this condition, generally assumed to be a major factor for suicidal behavior.

The strengths of this study include the large number of participants, and the fact that the cohort is derived from the general population.  Also the authors had data on good indices of alcohol misuse, including scores from the AUDIT test for misuse and a history of blackouts associated with excessive alcohol consumption.

The main weaknesses relate to its cross-sectional data collection (with a history of alcohol consumption and of suicidal behaviors being from the same previous year); hence, it is not possible to judge causation between the two.  Also, obviously, the study did not include any information related to “successful” suicidal attempts that may have occurred in this population prior to data collection.  Reviewer McEvoy stated: “I think that the authors appropriately acknowledged the cross-sectional limitation of their study, and inability to draw causal inferences.  I think one of the important contributions of this study is that it indicates that a pattern of excessive drinking, with black outs, may be risk factor for suicide.  Regardless of the direction of causality, this finding has clinical implications for intervention and treatment.”

Forum member McCormick added: “Correlation doesn’t mean cause, as we all know.  Alcohol might be part of the cause in heavy drinkers, but this paper doesn’t confirm that.”  Forum member Skovenborg agreed with the comments of other members: “This type of study, using cross-sectional data, cannot sort out the confounding issues nor address the causality of drinking volume and drinking patterns.  To my knowledge the egg and hen question has never been solved – whether the depression or the heavy drinking came first.”

Depression and suicidal tendencies:  Reviewer Finkel commented that “Depressive disease in one form or another is pervasive in our society. It is basically the cause of suicide.  I am unfamiliar with Korea, but would be surprised were things very different there.  More women than men attempt suicide, yet more men die of suicide, probably because the sexes choose different methods: men often shoot themselves in the head, usually fatal; women often take what seems an overdose of pills, not so lethal.  Again, I’m citing what I learned practicing in the western world.” He continued: “I would view the relationships exposed in this paper as most likely reflecting that depressed people are sometimes driven to drink to great excess, the more depressed, the more some drink.  Black-outs and suicides ensue.  I won’t deny that excessive drinking may loosen controls, thus making suicide more likely, but I believe the shoe fits the other way round most of the time. Obviously, the data available in this study cannot distinguish between the two directions.”

The epidemiology of suicide:  Forum member Thelle commented: “Suicide epidemiology is not a simple exercise.  I have recently been supervisor to a PhD student (Finn Gjertsen) on suicide statistics, and I have provided a few of her findings.”  Sections of the work of Giertsen that were provided by Thelle indicate that suicide rates are remarkably stable within populations, even though rates vary markedly across populations.  The causes of suicide are poorly defined: undoubtedly social factors within populations relate to suicide rates, with one hypothesis being that an imbalance between integration within the society and the amount of regulation imposed upon them may be important.  Others have suggested that suicide increases where there is “need, hunger, and unemployment.”

Forum member Ellison emphasized the large differences in suicide rates between populations.  “The present study had adequate numbers of subjects for study, as suicide in Korea is much more common than in Europe and North America.  However, there are large cultural differences between populations that limit the application of the findings in this study to other cultures.”  Reviewer Evans pointed out that there are large differences in the distribution of genes affecting the metabolism of alcohol and aldehyde (especially ADH1B and ALDH2) between people in the west and those in Korea; these may also relate to differences in the association of alcohol with suicide between the two cultures.

Reviewer McEvoy added: “I was struck by the differences in drinking patterns between women and men, with women drinking much less than men, and many more women reporting non-drinking.  I wonder if this reflects differences in societal acceptance of drinking among men and women, and whether women who drink regularly, or who have alcoholic tendencies, face greater censure than men, which could contribute to the greater risk of suicide/suicidal ideation among women at a lower level of alcohol use.  I think this may be an important area for future research that the authors missed emphasizing.”

Forum Summary

The present study evaluates the relation of alcohol consumption and the pattern of drinking with self-reports of suicidal ideation and suicidal attempts among more than 43,000 men and women in Korea, using data from a 2007-2011 survey.  Overall, 11.3% of males and 21.2% of females reported that they had experienced suicidal ideation, and 0.8% of males and 1.1% of females had attempted suicide.  High scores on the Alcohol Use Disorders Identification Test (AUDIT) and a history of alcoholic blackouts were associated with suicidal ideation among both men and women and, for males, with suicidal attempts.

There is little known about the epidemiology of suicidal tendencies, or the specific causes of suicide.  It is generally agreed that depression is the most important risk factor for suicide, and depression can lead to alcohol abuse; however, alcohol abuse can also lead to depression.  Unfortunately, with cross-sectional data, analyses such as those in this paper cannot sort out the confounding issues nor, more importantly, address the causality of alcohol consumption with suicidal tendencies.  The egg and hen question has never been solved – whether the depression or the heavy drinking came first.  Thus, whether alcohol abuse increases the risk of depression (that may lead to suicide) or whether depressed people turn to alcohol seeking relief, cannot be determined from analyses such as these.  However, it is also noted that this study suggests that drinking alcohol according to the usual guidelines for “sensible drinking” (generally, advising no more than 1 to 2 drinks/day) is not associated with the risk of suicidal ideation or attempt.

Forum members also commented on the large differences between populations in suicidal tendencies, being much higher in Korea and Japan than in most of Europe and North America.  This could limit the applicability of the conclusions of this study to western populations.

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Comments on this critique have been provided by the following members of the International Scientific Forum on Alcohol Research:

Harvey Finkel, MD, Hematology/Oncology, Boston University Medical Center, Boston, MA, USA

Giovanni de Gaetano, MD, PhD, Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, Italy

Ross McCormick, PhD, MSc, MBChB, Professor Emeritus, The University of Auckland; former Associate Dean, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand

Linda McEvoy, PhD, Department of Radiology, University of California at San Diego (UCSD), La Jolla, CA, USA

Erik Skovenborg, MD, specialized in family medicine, member of the Scandinavian Medical Alcohol Board, Aarhus, Denmark

Dag S. Thelle, MD, PhD, Senior Professor of Cardiovascular Epidemiology and Prevention, University of Gothenburg, Sweden; Senior Professor of Quantitative Medicine at the University of Oslo, Norway

Alun Evans, MD, Centre for Public Health, The Queen’s University of Belfast, Belfast, UK.

R. Curtis Ellison, MD. Section of Preventive Medicine & Epidemiology, Department of Medicine, Boston University School of Medicine, Boston, MA, USA