The aim of this study was to investigate risk factors, developmental pathways and the rate ofattempted or accomplished suicide in a longitudinal population-based prospective birth cohort.

The Northern Finland 1966 Birth Cohort (NFBC 1966) consists of 12,068 pregnant womenwith expected dates of delivery in 1966, and their 12,058 live-born children. The data used herewas collected prospectively for 10,934 individuals who were alive and resident in Finland at theage of 16. This study utilized an extensive data set collected in antenatal clinics at mid-pregnancy,by postal questionnaire at the age of 14 years and through national registers.

A total of 121 suicide attempts (57 males) and 69 suicides (56 males) had occurred by the endof 2005. A single-parent family was a risk factor for attempted suicides and grand multiparity forsuicides in male offspring. Adolescent regular smoking was associated with an increased risk ofsuicide attempts in both genders and for suicide among males. Good school performance at age 16years was associated with an increased risk of suicide in psychosis cases, whereas in persons whodid not develop psychosis it was associated with a lower suicide risk. The suicide rate in new-onsetschizophrenia followed until the age of 39 was 7%. Over two thirds of the suicides took placeduring the first 3 years of the illness.

This was the first study of suicide rates in a prospectively followed population-based birthcohort of individuals with schizophrenia. This study replicated association between some earlyfamily-related risk factors for attempted and accomplished suicide, and also presented data forpreviously unstudied early factors, namely maternal antenatal depression, smoking and unwantedpregnancy This study has clarified the association between adolescent smoking and later suiciderisk. It also revealed the association between good school performance and elevated risk of suicidein psychotic people, in contrast to its protective effect in the non-psychotic population.

However, even though there were significant antenatal and developmental risk factors, a laterpsychiatric disorder seems to be the major risk factor for both attempted and accomplished suicide.Nevertheless, suicide usually seems to be a long multifactorial process that begins in early life andhas complex trajectories in adolescence or early midlife.