This study examined the prevalence and risk of psychiatric disturbances and suicidal
behaviours among the peers of suicide attempters and completers. The subjects were selected
from high schools with and without history of student suicides in the past 3 years. The
psychiatric disturbances (as measured by the YSR and CBCL), suicidal behaviours, drug
use, and a wide range of potential risk factors were measured. About a quarter of the peers
of suicide completers and attempters were probable psychiatric cases and 15–21% of them
reported suicidal acts. The increased risk of psychiatric disturbances and suicidal behaviours
were still evident after controlling for age, sex, and potential risk factors. The presence of
psychiatric disturbances could not wholly account for the increased odds of suicidal
behaviours. 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 peers of suicide completers and attempters represent a high-risk group for psychiatric
disturbances and suicidal behaviours. The specific association of different types of psychiatric
disturbances in the peers of suicide completers and attempters suggested that different risk
mechanisms might be in operation within these peer groups.