To date, the proposition of recurrence as a subclinical bipolar disorder feature has not received adequate testing.
We used the Italian version of the bipolar spectrum diagnostic scale (BSDS), a self-rated questionnaire of bipolar risk, in a sample of patients with mood disorders to test its specificity and sensitivity in identifying cases and discriminating between high risk for bipolar disorder major depressive patients (HRU) and low risk (LRU) adopting as a high recurrence cut-off five or more lifetime major depressive episodes.
We included 115 patients with DSM-5 bipolar disorder (69 type I, 41 type II, and 5 NOS) and 58 with major depressive disorder (29 HRU and 29 LRU, based on the recurrence criterion). Patients filled-out the Italian version of the BSDS, which is currently undergoing a validation process.
The BSDS, adopting a threshold of 14, had 84% sensitivity and 76% specificity. HRU, as predicted, scored on the BSDS intermediate between LRU and bipolar disorder. Clinical characteristics of HRU were more similar to bipolar disorder than to LRU; HRU, like bipolar disorder patients, had more lifetime hospitalizations, higher suicidal ideation and attempt numbers, and higher rates of family history of suicide.
The BSDS showed satisfactory sensitivity and sensitivity. Splitting the unipolar sample into HRU and LRU, on the basis of the at least 5 lifetime major depressive episodes criterion, yielded distinct unipolar subpopulations that differ on outcome measures and BSDS scores.
The authors have not supplied their declaration of competing interest.