Sleep disruption as a pathway to mania in bipolar disorder

Sleep loss may act as a trigger or early warning sign of manic episodes in individuals with bipolar disorder (BD) but the nature of this relationship remains unclear. The aim of this thesis was to explore the relationship between sleep disruption and mania in individuals with BD. \nThe datasets used in this thesis were obtained from the Bipolar Disorder Research Network (BDRN), an ongoing research programme of over 6000 individuals with mood disorders recruited from across the UK. Psychiatric diagnoses were determined using a semi-structured diagnostic research interview and case notes. \nFirst, in 3140 BDRN participants with bipolar-I disorder (BD-I) or bipolar-II disorder (BD-II), I found that 20% of participants reported that sleep loss had triggered episodes of high mood. This was more commonly reported by individuals with BD-I than those with BD-II, and more commonly reported by women than men. \nSecond, I found that women were more likely to have experienced episodes of mania or psychosis after childbirth (termed postpartum psychosis, PP) if sleep loss had triggered episodes of high mood. This effect suggested that a tendency for sleep loss to trigger episodes of high mood might be associated with vulnerability to PP. \nThird, in BDRN participants who had used an online mood monitoring system to track symptoms of mania and depression, I found that participants could be grouped into three classes based on their trajectories in symptoms of insomnia prior to episodes of high mood. \nFinally, I designed and conducted a pilot study using actigraphy to measure perinatal sleep in pregnant women at high risk of developing PP. I found that this methodology was challenging to implement in this population but can produce detailed information on sleep during the perinatal period. \nThe findings of this thesis could help inform clinical practice by expanding current knowledge on how sleep loss affects individuals with BD.