The relationship between suicidal ideation and symptoms of depression in Japanese workers: a cross-sectional study

The prevalence of suicidal ideation and predictors for suicidal ideation among Japanese workers is unknown, although a previous study reported a 30% prevalence rate of suicidal ideation in a psychosomatic clinical setting. Hence, we evaluated the prevalence of suicidal ideation and its relationship with depressive symptoms among Japanese workers.

For this purpose, a cross-sectional design was used. Major depressive disorder (MDD) and suicidal ideation in 1266 workers (1100 men and 166 women, aged 20-69 years) were assessed through clinical interviews conducted in accordance with the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders.

A total of 34 and 70 participants were diagnosed with suicidal ideation and MDD, respectively. Suicidal ideation was especially prevalent in 40-year-olds to 49-year-olds. Six of the eight symptoms of MDD (depressive mood, loss of interest, weight loss, psychomotor agitation, worthlessness and concentration loss) were related to suicidal ideation. Depressive mood had the strongest relationship with suicidal ideation, followed by worthlessness and concentration loss. Worthlessness had the highest area under the curve in predicting suicidal ideation, followed by concentration loss and depressive mood.

We conclude that MDD symptoms-particularly depressive mood, worthlessness and concentration loss-are potential predictors of suicidal ideation in Japanese workers.