Aims: 1. To measure and report the lifetime experience of manic symptoms within the ALSPAC cohort at age 21+ using the Hypomania Checklist 32 (HCL-32), a well validated self-report questionnaire for the identification of manic symptoms. 2. To use existing data on the cohort to identify risk factors for the experience of significant manic symptoms by age 21+. 3. To use existing prospective data on the cohort to 'map out' the trajectory of symptoms in individuals who appear to either have bipolar disorder or be at very high risk of developing bipolar disorder.

Hypotheses: In order to address Aim 3 of this study (mapping the 'bipolar prodrome'), we will use existing prospective measurements of cognitive function, anxiety symptoms, depressive symptoms and psychosis-like experiences to assess whether there exists an identifiable trajectory of symptoms which predicts the experience in late adolescence/early adulthood of manic symptoms.