The association of alcohol & drugs with suicidal thinking & behaviour is both causal & conductive. Alcohol & drugs are influential in providing a feeling of hopelessness by manipulating neurotransmitters responsible for mood & judgement & by disrupting interpersonal relationships & social supports. Over 50% of all suicides are associated with alcohol or drug dependence. Any alcoholic or drug addict should be assessed for suicide, especially if actively using alcohol or drugs. (33 refs.)