Although Parkinson's disease has a definite neurologic basis, patients and relatives experience a multitude of stresses, only partly related to motor symptoms. Subjective and behavioral problems may be regarded as secondary disease symptoms. In an integrated approach, patients and relatives receive psychological counseling and learn new coping strategies for everyday situations. Results show that even elderly patients can make use of structured psychological interventions and change dysfunctional behaviors and cognitions. Measures specifically adjusted to Parkinson's disease are aimed at helping patients make better use of the beneficial effects of medication and counteract the possible negative effects of social and emotional stressors. Relatives need information about the disease and training to cope adequately with difficult caring situations. Future evaluation of medical treatment of Parkinson's disease should consider the interaction of psychological factors and symptom intensity. This interaction may result in momentary changes in the effects of medication because of psychological conditions. In the early stages of the disease, medication has the most positive effect, and psychological interventions should also have the most benefit.