Treatment of sleep dysfunction and psychiatric disorders.

Patients with neurologic disorders commonly experience sleep dysfunction and psychiatric disorders. The most common sleep dysfunction is insomnia, which is a primary symptom in 30% to 90% of psychiatric disorders. Insomnia and fatigue are prominent symptoms of anxiety disorders and major depression that may occur in patients who are treated but have residual sleep dysfunction. Anxiety and depressive disorders account for 40% to 50% of all cases of chronic insomnia. It is also recognized that primary insomnia and other primary sleep disorders produce symptoms that are similar to those reported by patients with psychiatric disorders. A clinician must judge whether sleep deprivation causes mood disturbance or whether depressive or anxiety disorder represents the primary reason for sleep dysfunction. When insomnia is comorbid with mild to moderate depression, therapy should begin with bedtime dosing of sedating antidepressants such as mirtazapine, nefazodone, or tricyclic antidepressants, which are preferred because of their sedative effects. Often side effects limit their usefulness. Intervention for chronic insomnia is similar in nonpsychiatric and psychiatric patients. Behavioral therapies, particularly multicomponent cognitive-behavioral therapy, and lifestyle changes show significant long-term efficacy as treatments for chronic insomnia. The most studied pharmacologic agents to treat insomnia are sedative hypnotic agents, particularly those that are active through the benzodiazepine receptor-GABA (gamma-aminobutyric acid) complex, such as benzodiazepines, eszopiclone, zaleplon, and zolpidem. Melatonin and the melatonin-receptor agonist ramelteon have not had adequate study in psychiatric patients to define their use, but small studies suggest benefit. Prescription of adjunctive trazodone (50-150 mg) is a common clinical practice to treat comorbid insomnia during antidepressant therapy, but published data are surprisingly limited, considering its frequent use. Although there has been insufficient research on the use of atypical antipsychotic agents in severe insomnia, psychiatrists use quetiapine, olanzapine, or others to lessen agitation that disrupts sleep. When insomnia or hypersomnia continue even as mood, anxiety, or thought disorders improve with standard therapy, the physician should consider the potential presence of underlying sleep disorders.