This study examined the prevalence & risk of psychiatric disturbances & suicidal behaviours among the peers of suicide attempters & completers. The subjects were selected from Hong Kong high schools with & without a history of student suicides in the past 3 years. About a quarter of the peers were probable psychiatric cases & 15-21% of them reported suicidal acts. Peers of suicide attempters carried a higher risk than peers of suicide completers. The close friends of suicide completers were particularly at risk of internalising problems, whereas the close friends of suicide attempters were at high risk of externalising problems. The association of different types of psychiatric disturbances in the 2 groups suggests different risk mechanisms might be in operation within these peer groups. (25 refs.)