Sleep and psychopathology

This article examines the relationship between sleep disturbance and psychopathology. Epidemiological, cross-sectional, and longitudinal data suggest a high rate of comorbidity between sleep disturbance and psychopathology, particularly between insomnia, anxiety, and depression. Between 50% and 80% of psychiatric patients complain of sleep disturbances during the acute phase of their illness. Conversely, among treatment-seeking individuals with a primary complaint of insomnia and randomly selected community samples, approximately one third display a concurrent psychopathology, one third exhibit psychological symptoms that do not necessarily exceed the threshold for a psychiatric disorder, and another third present insomnia as a functionally autonomous disorder. There is a positive relationship between severity of sleep disturbances and concurrent psychopathology, but unequivocal evidence of a cause-and-effect relationship is still lacking. However, longitudinal data suggest that anxiety and stressful life events often precede acute sleep difficulties, whereas persistent insomnia may be a risk factor for subsequent development of depression. Implications for the prevention and treatment of coexisting sleep disturbance and psychopathology are discussed.