About 90% of people in Western countries use alcohol at some time in their lives, and 40% experience temporary or permanent alcohol-related impairment in some area of life as a result of drinking. Multiple sociocultural and environmental factors influence suicide rates, and thus studies conducted in one nation are not always applicable to other nations. Impulsivity and aggression are strongly implicated in suicidal behaviour. Constructs related to aggression and impulsivity confer additional risk for suicidal behaviour in people with alcohol dependence. Lower serotonin activity is tied to increased aggression/impulsivity, which in turn may enhance the probability of suicidal behaviour. Acute alcohol use is associated with suicide. Suicide completers have high rates of positive blood alcohol. Intoxicated people are more likely to attempt suicide using more lethal methods. Alcohol may be important in suicides among individuals with no previous psychiatric history. Alcohol dependence is an important risk factor for suicidal behaviour. Mood disorder is a more powerful risk factor for suicide among problem drinkers as age increases. All individuals with alcohol use disorders should be assessed for suicide, especially at the end of a binge or in the very early phase of withdrawal. Middle-age and older men with alcohol dependence and mood disorders are at particularly high risk.