• age of onset;
  • at-risk mental state;
  • bipolar disorder;
  • early detection of disease;
  • prodromal symptoms


Aim: Symptom instances characterized as episodic or chronic, and as exaggerated responses to life events or inexplicable (e.g. mood swings, irritability/aggressiveness), may be the most likely early manifestations of the first episode of bipolar II disorder (BD-II). Assuming that symptoms that emerge late in the prodrome, to a larger extent, are early manifestations of the disorder itself, we explore the time of onset and the duration of instances classified as ‘likely’, ‘possible’ and ‘unlikely’ early manifestations.

Methods: Retrospective interviews of 15 BD-II patients and 22 family members.

Results: ‘Likely’ early manifestations do, to a larger extent than other symptom instances, emerge late in the prodrome. The mean time interval between symptom onset and the first episode is shorter for the ‘likely’ than for the ‘unlikely’ early manifestations but is similar to the ‘possible’ ones.

Conclusions: Symptom instances classified as ‘likely’ early manifestations may be the most useful to prospectively predict BD-II.