Subthreshold manic symptoms as a risk factor for depressive, anxiety and substance use: Results of a prospective study in the general population.

Background: Indicated prevention aimed at high-risk individuals with subthreshold psychiatric symptoms should alleviate the disease burden caused by depressive, anxiety, and substance use disorders (further called: common mental disorders, CMD). This study investigates subthreshold manic symptoms (subM) as a possible risk factor for CMD and, for comparison, bipolar disorder type I and II (BD).

Methods: We assessed three-year manifestation of CMD and onset of BD in an adult cohort (n = 4618) representative of the Dutch general population. SubM was defined as elevated mood or irritability lasting at least four days, without meeting DSM-IV criteria for BD. Manifest CMD were absent at baseline and present in the subsequent three years, irrespective of lifetime occurrence (manifestation = onset and recurrence). Onset BD was absent at lifetime and baseline and present in the subsequent three years.

Results: Individuals with subM had a significantly increased risk of manifest depressive (odds ratio (OR) 2.3-2.9; p for trend < 0.001) and anxiety disorders (1.5-5.9; <0.001) and of onset BD (6.4-43.8; <0.001), but not of substance use disorders, as compared to those without manic symptoms. BD risk was elevated strongest. Increased risks persisted after adjustment for sociodemographic variables, presence of other CMD and lifestyle factors.

Conclusions: SubM precedes forthcoming depressive, anxiety and bipolar disorders on short term. Their presence should be considered a relevant predictor in the psychopathological pathway of mood- and anxiety disorders. Moreover, we recommend to include subM in research on risk prediction tools and preventive interventions for mood- and anxiety disorders.