Suicidal behaviour is actually understood as being multidetermined and the result of an interaction between state and trait related effects. Several types of risk factors have been extensively studied: psychiatric and personality disorders, genetic variables, biological factors and psychosocial stressors, the latter being the purpose of this review. Social and familial factors, negative life events and medical illness may interact with the factors mentioned above in three main ways to produce suicidal acts: as predisposing factors increasing vulnerability, as precipitating or as contributing factors. A summary of social and clinical studies will be presented and implications for medical care and prevention will be discussed.