Sleep loss as a trigger of mood episodes in bipolar disorder: individual differences based on diagnostic subtype and gender

Background Sleep loss may trigger mood episodes in people with bipolar disorder but individual differences could influence vulnerability to this trigger. Aims To determine whether bipolar subtype (bipolar disorder type I (BP-I) or II (BD-II)) and gender were associated with vulnerability to the sleep loss trigger. Method During a semi-structured interview, 3140 individuals (68% women) with bipolar disorder (66% BD-I) reported whether sleep loss had triggered episodes of high or low mood. DSM-IV diagnosis of bipolar subtype was derived from case notes and interview data. Results Sleep loss triggering episodes of high mood was associated with female gender (odds ratio (OR) = 1.43, 95% CI 1.17–1.75, P < 0.001) and BD-I subtype (OR = 2.81, 95% CI 2.26–3.50, P < 0.001). Analyses on sleep loss triggering low mood were not significant following adjustment for confounders. Conclusions Gender and bipolar subtype may increase vulnerability to high mood following sleep deprivation. This should be considered in situations where patients encounter sleep disruption, such as shift work and international travel.