Objective: The author hypothesized, based on research until 1991, that a five-fold increase in the use of antidepressants might reduce Swedish suicide rates by 25%. A subsequent 3.5-fold increase in the use of antidepressants provided a 'natural experimental situation' for prospectively testing this hypothesis.
Method: Swedish statistics on suicide, use of antidepressants, unemployment and alcohol consumption were obtained for 1978-96. Time-series of the latter variables were compared with suicide rates. Demographic subgroups regarding age, gender and county were analysed. Suicide rates were also compared with the use of antidepressants in Denmark, Norway and Finland.
Results: Suicide rates decreased in accordance with the a priori hypothesis. Alcohol consumption and unemployment rates did not correlate well with suicide rates.
Conclusion: This naturalistic study is not conclusive. The increased use of antidepressants appears, however, to be one of the contributing factors to the decrease in the suicide rate. It is of great scientific and clinical importance that this be evaluated by further studies.