A musculoskeletal disease frequently entails numerous physical, social and occupational limitations, e.g. reduction of physical capabilities, chronic pain, and loss of employment. A number of patients suffer from comorbid psychological strain or mental disorders, and it frequently remains unclear whether these psychological phenomena are unconnected to, a consequence of or even among the causes for the somatic disease. In order to diagnose, or possibly prevent, comorbid mental disorders, it is necessary to know risk factors which are associated with mental disorders. Studies published during the last twenty years are reviewed which examine sociodemographic, disease specific and psychosocial factors in connection with psychological strain or mental disorders among patients with musculoskeletal diseases. Due to the relatively small number of relevant studies (n = 12), the findings have to be interpreted carefully.