The Bipolar Spectrum
The chapter discusses disorders in the bipolar spectrum. Bipolar disorders (BDs) and cyclothymic disorder are marked by mania, a state of abnormally high energy and activity coupled with persistently elevated, expansive, or irritable mood. After an overview of these disorders, their developmental features, and the main risk factors identified in the epidemiological literature, the chapter critically reviews existing evolutionary models and suggests new directions for research. The final section applies the criteria developed earlier in the book to classify the disorders within the fast-slow-defense (FSD) model and identify functionally distinct subtypes. The author proposes to tentatively distinguish between two subtypes of BDs: a high-frequency fast spectrum subtype (F-BD) with strong links to schizophrenia and a low-frequency slow spectrum subtype (S-BD) marked by higher comorbidity with autism.