The contribution of sleep medicine to the assessment of the tired patient.

Tiredness is one of the most common complaints that confront the clinician. Yet the nature of the symptom and its implications for sleep-related disorders is poorly understood. This review provides the clinician with an understanding of the difficulties inherent in assessing the tired patient. The complaint of tiredness is commonly an expression of sleepiness and fatigue that arises as the result of sleep-wake-related disorders. Behavioural and physiological procedures are described in the assessment and management of sleepiness and fatigue in primary sleep disorders and sleep-related medical and psychiatric disorders. Improvement in the diagnosis and management of the fatigued or sleepy patient requires that residents in psychiatry and neurology be exposed to the behavioural and physiological techniques of sleep medicine as part of their post-graduate training programs.