BACKGROUND Although the motor symptoms of Parkinson's disease (PD) dominate the clinical picture, the nonmotor complaints are often more disabling for the Parkinson patient. REVIEW SUMMARY Behavioral, psychiatric, and cognitive changes occur commonly and are frequent causes for concern. Depression affects up to half of Parkinson patients and can worsen their motor function. Drug-induced psychoses can range from benign visual hallucinations to paranoid delusions. Dementia, classically described as subcortical, usually occurs in the elderly PD patient and is often clinically distinct from the cortical dementia of Alzheimer's disease although pathological descriptions overlap. A parkinsonian personality has been noted by psychoanalysts and movement disorder experts characterized as rigid and compulsive yet cautious and apprehensive with a subordinate behavior. Sleep disturbances associated with PD include insomnia, sleep fragmentation, daytime somnolence, vivid dreams, rapid eye movement behavior disorder, and restless legs syndrome. Sensory symptoms, including pain, may occur, as do symptoms of autonomic dysfunction including postural syncope. Problems with bladder and bowel control and sexual dysfunction are common and often distressing to both the patients and their partners. Fatigue, akathisia, seborrheic dermatitis, and scoliosis are conditions intrinsic to or aggravated by PD. Most of these problems are amenable to pharmacologic and nonpharmacologic treatments. CONCLUSION Helping patients with PD cope with these difficulties is just as important as manipulating therapy to provide control of their motor symptoms. (THE NEUROLOGIST 6:18-27, 2000)