Insomnia and psychiatric disorders

Insomnia was originally considered a symptom of psychiatric morbidity and not a separate form of disease. It was not until recently that sleep continuity disturbance (i.e., insomnia) was wholly recognized as an independent disorder. The impetus for this change in classification is related to a variety of factors including multiple demonstrations that chronic insomnia: (1) appears to have a unique etiology and pathophysiology; (2) occurs prior to, and represents a risk factor for, new onset and recurrence of multiple psychiatric disorders; (3) often persists following the successful treatment of the comorbid disorder(s); and (4) CBT-I (the indicated treatment for insomnia) may serve to augment standard treatment outcomes for other disorders (e.g., major depression). The clear implication is that, when chronic, insomnia should be targeted for treatment, regardless of the psychiatric disorders that occur concurrently. The goal of the present chapter is to review each of these issues in detail.