Purpose of review: An overview of the current status of dream science is given, designed to provide a basic background of this field for the sleep-interested physician.
Recent findings: No cognitive state has been more extensively studied and is yet more misunderstood than dreaming. Much older work is methodologically limited by lack of definitions, small sample size, and constraints of theoretical perspective, with evidence equivocal as to whether any special relationship exists between rapid eye movement (REM) sleep and dreaming. As the relationship between dreams and REM sleep is so poorly defined, evidence-based studies of dreaming require a dream report. The different aspects of dreaming that can be studied include dream and nightmare recall frequency, dream content, dreaming effect on waking behaviors, dream/nightmare associated medications, and pathophysiology affecting dreaming.
Summary: Whether studied from behavioral, neuroanatomical, neurochemical, pathophysiological or electrophysiological perspectives, dreaming reveals itself to be a complex cognitive state affected by a wide variety of medical, psychological, sleep and social variables.