Book excerpt: This practical, clinically oriented handbook provides up-to-date information on the concept, causality, diagnosis, and pharmacologic and behavioral treatment of hypomania, an increasingly recognized stage of bipolar illness often referred to as "elevated mood." The first section traces the evolution of the concept of elevated mood, including the bipolar spectrum model and the GEnES fingerprint, a new model for understanding the role of both neurocellular and environmental factors in mood disorders. Subsequent sections address diagnostic issues, provide evidence-based treatment recommendations, and discuss the management of symptoms, populations, and comorbid conditions that pose special challenges. An appendix lists Internet resources for patients.