Introduction: The majority of patients with mental disorders is treated by general practitioners. Objectives: Goal of the present study is to investigate the proportion, type, course, and impairment of general practice patients who are suffering from chronic mental disorders. Methods: 1451 general practice patients, aged 18 to 60, were screened. 307 patients, who had indicated that they were suffering from chronic and disabling mental problems underwent a medical assessment with the standardized International Neuropsychiatric Interview, the Burvill Rating for somatic disorders, the SCL-90, Mini-ICF-APP for capacity limitations and the IMEP for participation restrictions. Results: 29.7% of all general practice patients reported to suffer from mental problems with relevant impairment in their daily living. From the 307 patients 55.4% had additionally seen a psychiatrist or psychotherapist during the last year. 28.8% were at present on sick leave. Frequent limitations in capacity are seen for flexibility (57% all, or 5.2% very severe), decision making (57.9%, or 2.9%), endurance (55.3%, or 7.8%), assertiveness (53.4%, or 2.9%), contact to others (50.1%, or 1.6%), intimate relationships (52.8%, or 3.9%), and spontaneous activities (73.3%, or 3.9%). Conclusions: Chronic and disabling mental disorders are frequent in primary health care. Cross-sectionally they look not very impressive, but in respect to negative illness consequences and restrictions in participation they are disabling. The data show that general practitioners are, to a large degree, therapists for mental disorders. As most cases are chronic and disabling general practitioners must work not so much in a curative but rather rehabilitation perspective.