Background: It is known that mental illness is associated with increased suicide risk. It has been postulated that suicidality may be an independent clinical phenomenon and we investigate whether variability of mood may be a mediator of this.
Methods: Fifty-three psychiatric inpatients were assessed on the Montgomery-Asberg depression rating scale, once weekly, over a 4-week period. The SCID II was administered to diagnose co-morbid personality disorder. Hostility was measured with the Hostility and Direction of Hostility questionnaire. A Fluctuation Index score was calculated to measure variability of mood.
Results: Unadjusted analyses suggested that patients with a history of deliberate self-harm showed greater variability in mood as measured by the fluctuation index (mean difference=13.4; 95% CI=4.3 to 22.6; P=0.005) though this relationship was no longer significant at the 5% level after adjustment (mean difference=13.4; 95% CI=-2.0 to 28.8; P=0.09).
Limitations: There was a high initial dropout rate from the study and a small sample size. A prospective study would have more power in determining the effect of mood fluctuations.
Conclusions: Mood fluctuation may be a useful indicator of risk of deliberate self-harm and attempted suicide.