The presence of an alcohol use disorder increases suicide risk. Estimates based on computerized curve fitting of data from 27 studies have suggested a 7% lifetime risk of suicide in individuals with alcohol dependence (94). Other approximations of lifetime suicide risk have ranged from 3.4% to as high as 15% (148, 157) but vary by country and depend on the definition of alcoholism used. In fact, the vast majority of studies have not used the DSM-IV criteria for alcohol use disorders, making comparisons across studies difficult. As a result, descriptions of studies in this document will use the diagnostic terms employed by the study authors.

Harris and Barraclough (64) used data from 32 publications, including findings for more than 45,000 individuals with follow-up periods for up to 30 years, to calculate an SMR for suicide of 5.86 among persons with alcohol abuse or dependence. The overall suicide rate for women with alcohol abuse or dependence was about 20 times the expected rate, whereas the rate for men was only about four times the expected rate. Beck et al. (227) also found a risk of suicide in alcoholics that was about fivefold greater than in nonalcoholics in a sample of 413 patients hospitalized for a suicide attempt and prospectively followed for 5–10 years. They also noted that the timing of suicides was spread throughout the follow-up, with no particular period of increased risk.

The association between alcohol use disorders and suicide is also demonstrated by psychological autopsy studies, which show alcohol use disorders to be common among individuals who die by suicide. For example, Henriksson et al. (59), in a random sample of 229 Finnish suicide deaths during a 1-year period, found that alcohol dependence was present in 43% of cases. In the United States, Conner et al. (150) found that 39% of 141 individuals who died by suicide over a 2.5-year period had had a history of alcohol use disorder.

Significant rates of alcohol use were also seen in a sample of youth suicides that included older adolescents. Brent et al. (151) examined death certificates and coroners' reports for all suicides, undetermined causes of death, and questionable accidents for 10- to 19-year-old residents of Allegheny County, Pennsylvania, from 1960 to 1983. Altogether, 159 definite suicides and 38 likely suicides were noted, but the suicide rate increased markedly over the study period, particularly among white males ages 15–19 years. During the study period there was also a 3.6-fold increase in the percentage of suicides with detectable blood alcohol levels (12.9% in 1968–1972, compared to 46.0% in 1978–1983). In addition, the rate of suicide by firearms increased much faster than that by other methods (2.5-fold and 1.7-fold, respectively), and persons who died by suicide with firearms were almost five times more likely to have been drinking than individuals who used other suicide methods.

A number of factors have been specifically observed with suicide in individuals with alcohol use disorders (153). Murphy et al. (152), in a study of 50 alcoholics who died by suicide, found that 26% had experienced interpersonal loss within 6 weeks of their death. These findings were comparable to those in a prior group of 31 alcoholics who died by suicides, one-third of whom had experienced the loss of a close interpersonal relationship within 6 weeks of the suicide. An earlier study by Murphy and Robins (156) also found a high proportion of recent interpersonal disruptions, as did a study of suicides in San Diego by Rich et al. (67). To identify other factors associated with increased risk for suicide among alcoholics, a subsequent study by Murphy et al. (149) pooled these two similar groups of alcoholics who died by suicide and compared them to two control samples of white male alcoholics, one from a psychiatric patient population and one from the ECA community-based population. Clinical features that were significantly more frequent among those who died by suicide than among the control subjects included current alcohol use, poor social support, serious physical illness, unemployment, living alone, and having made a suicidal communication. Eighty-three percent of the alcoholics who died by suicide had four or more of the seven risk factors.

Pirkola et al. (154) also examined factors associated with increased likelihood of suicide among alcohol misusers. They found that alcohol misusers who died by suicide (N=349) were more likely to be young, male, and divorced or separated, compared with individuals who did not misuse alcohol in the several months preceding their suicide (N=648). Alcohol misusers were also more likely to be intoxicated with alcohol at the time of death or to have died from an overdose of medications. Those with alcohol misuse had also experienced more adverse life events close to the time of their suicide despite having better psychosocial adjustment earlier in their lifetime. For example, alcoholics who died by suicide had more often worked but were also more likely to be recently unemployed.

A number of studies have identified comorbid disorders as being common among individuals with alcohol use disorders who die by suicide. In a series of 1,312 alcoholics admitted to a Swedish psychiatric hospital between 1949 and 1969 and followed through 1980, Berglund (157) found that alcoholics who died by suicide had a higher rate of depressive and dysphoric symptoms than alcoholics who died of other causes or who were alive at the end of the follow-up period. Murphy et al. (152) also found that concurrent depression was present in most but not all of their sample of alcoholics who died by suicide, suggesting that depression was neither a necessary nor a sufficient precondition for suicide. In a later study, Murphy et al. (149) found that major depressive episodes were significantly more frequent among alcoholics who died by suicide than among alcoholic control subjects and also found that 58% of the alcoholics who died by suicide had comorbid major depression.

Shaffer et al. (159) compared 120 individuals under age 20 who died by suicide to 147 age-, sex-, and ethnicity-matched community control subjects and found that 59% of the subjects who died by suicide and 23% of the control subjects met the DSM-III criteria for a psychiatric diagnosis based on information obtained from the subject's parents. When information from multiple informants was obtained, 91% of the subjects who died by suicide met the criteria for a DSM-III psychiatric diagnosis. In addition, with increasing age, there was an increased prevalence of a psychiatric diagnosis in general and of a substance and/or alcohol use disorder in particular. Previous suicide attempts and mood disorders were risk factors for suicide in both male and female subjects, whereas substance and/or alcohol abuse occurred exclusively in males and was present in 62% of 18- to 19-year-old subjects who died by suicide.

Even in individuals whose alcohol use disorder has remitted, suicide risk may still be increased but is likely to be influenced by comorbid disorders. Conner et al. (150) analyzed data from a community sample of 141 individuals who died by suicide and found that 39% (N=55) had a history of alcohol misuse. Compared with those who were actively using alcohol, those with remitted alcohol use disorders were predominantly younger individuals with psychotic disorders or older individuals with major depression.

In addition to being associated with an increased risk of suicide, alcohol use disorder is associated with a greater likelihood of suicide attempts. For example, Petronis et al. (163) analyzed data from 13,673 participants in the ECA survey and found that active alcoholism was associated with an 18-fold increase in the relative odds of making a suicide attempt. Gomberg (162) compared 301 women admitted to 21 alcohol treatment facilities to an equal number of age-matched nonalcoholic women from the community. Alcoholic women were far more likely to have attempted suicide (40%, compared with 8.8% of nonalcoholic women), and suicide attempts were particularly likely among alcoholic women under age 40. Alcoholic women who had attempted suicide were more likely to have used other drugs, and they reported significantly more tension, explosiveness, indecisiveness, fearfulness/anxiety, and difficulty concentrating and getting up in the morning.

Among alcoholics, differences also have been noted between those who attempt suicide and those who do not. Roy et al. (165), for example, performed a case-control study to determine the differences between alcoholic suicide attempters and alcoholic nonattempters. Of the 298 alcoholic patients studied, 19% had attempted suicide. Compared with the nonattempters, the attempters were significantly more likely to be female, to be young, and to have a lower economic status. They also were more likely to have first- or second-degree relatives who abused alcohol, to consume a greater amount of alcohol when drinking, and to have begun heavy drinking and experienced the onset of alcohol-related problems at an earlier age.

In addition, comorbid diagnoses are frequently identified among alcoholics who attempt suicide. Roy et al. (165), for example, found the most common comorbid psychiatric diagnoses among alcoholic suicide attempters to be major depression, antisocial personality disorder, substance abuse, panic disorder, and generalized anxiety disorder. Hesselbrock et al. (166), in a sample of 321 inpatients (231 men, 90 women) in alcoholism treatment centers, found that suicide attempters typically had multiple psychiatric diagnoses (e.g., depression, antisocial personality disorder, and substance abuse) and more severe psychiatric symptoms than nonattempters. Two-thirds of alcoholics who attempted suicide had a lifetime diagnosis of major depressive disorder, and most reported symptoms of depression within 2 weeks of the interview. Alcoholic suicide attempters tended to have a parental history of alcoholism, to have begun abusing alcohol at an early age, and to have abused other substances in addition to alcohol.

Preuss et al. (167), using data for 3,190 alcohol-dependent individuals from the Collaborative Study on the Genetics of Alcoholism, found that alcohol-dependent individuals with a history of suicide attempts were more likely to be dependant on other substances and more likely to have other psychiatric disorders. In addition, subjects with suicide attempts had a more severe course of alcohol dependence and more first-degree relatives with suicide attempts. In a subsequent study that followed 1,237 alcohol-dependent subjects over 5 years, Preuss et al. (168) found that the 56 alcohol-dependent subjects with suicide attempts during the follow-up period were more likely to have a diagnosis of a substance-induced psychiatric disorder or be dependent on other drugs. Furthermore, among 371 alcohol-dependent individuals who had made a suicide attempt and also had had an episode of depression, the 145 individuals (39.1%) with alcohol-independent mood disturbance had a greater number of prior suicide attempts and were more likely to have an independent panic disorder but reported a less severe history of alcohol dependence and were less likely to have been drinking during their most severe attempt (169). These findings suggest that in taking a clinical history in suicide attempters it is useful to identify comorbid depression but also to determine whether depressive episodes are alcohol induced or not.

That the presence of prior attempts is predictive of future attempts also highlights a need for taking a thorough history of past suicidal behaviors. Preuss et al. (168) followed 1,237 alcohol-dependent subjects over 5 years and found that the 56 alcohol-dependent subjects with suicide attempts during the follow-up period were more likely to have made prior attempts than subjects with no suicide attempts. Persons with comorbid major depression and alcohol use have higher rates of suicidal symptoms than those with either alone. Cornelius et al. (170) compared 107 patients with both major depression and alcohol dependence to 497 nondepressed alcoholics and 5,625 nonalcoholic patients with major depression assessed at the same psychiatric facility using a semistructured initial evaluation form. Depressed alcoholics had a significantly greater degree of suicidality, as reflected by a global measure that included wishes for death, suicidal ideation, and suicidal behaviors. They also differed significantly from the nonalcoholic depressed patients in having lower self-esteem and greater impulsivity and functional impairment.

In a subsequent study, Cornelius et al. (171) found that among psychiatrically hospitalized alcoholics with major depression, almost 40% had made a suicide attempt in the week before admission, with 70% having made a suicide attempt at some point in their lifetime. There was a significant association between recent suicidal behavior and recent heavy drinking, with most subjects also reporting drinking more heavily than usual on the day of their suicide attempt. In addition, these suicide attempts were usually impulsive. Suicidal ideation, however, was not increased by more recent heavy alcohol use, suggesting that alcohol increases suicidal attempts by increasing the likelihood of acting on suicidal ideation.

In summary, alcohol use disorders are associated with increased risks of suicide and suicide attempts. Conversely, rates of alcohol use disorders are elevated among those who die by suicide as well as among suicide attempters. The common occurrence of comorbid psychiatric symptoms and diagnoses suggests a need for thorough assessment and treatment of such complicating factors in users of alcohol. Also, the frequent presence of psychosocial stressors including unemployment and interpersonal losses should also be taken into consideration in the assessment and treatment planning process.