The aim of this research was to study the role and trend of antidepressant use as a method of suicide in completed self-poisoning suicides in patients with affective disorders during a 23-year follow up period. The data consisted of 483 completed self-poisoning suicides from 1988 to 2011 in the province of Oulu in Northern Finland (286 men and 197 women). Of the self-poisoning victims, 26.9% (n=130) had hospital-treated unipolar depression and 3.1% (n=15) hospital-treated bipolar disorder. Further, 53.8% (n=70) of those with unipolar depression and 53.3% (n=8) of those with bipolar depression died by suicide using antidepressants. During the 23-year follow-up period, the proportion of those using antidepressants doubled among all self-poisoning victims of suicide. A significant decline was observed in the use of tricyclic antidepressants in self- poisoning suicides while a linear increase was found in the use of SSRIs (selective serotonin reuptake inhibitors) and other antidepressants. During recent years one in five self-poisoning suicides involved the use of antiepileptics. A limitation of our study was that the psychiatric diagnoses only include hospital inpatient episodes. In conclusion, the use of new antidepressants has increased rapidly, but the risk of their use in self-poisoning suicide has perhaps been underestimated.