CL psychiatry is one of the newer sub-specialties of adult psychiatry and is concerned with the practice of psychiatry in non-psychiatric settings. Typically, this means in general hospital wards and outpatient clinics, although in some countries, it also includes liaison with primary care. In recent years, there have been important changes in general medicine relevant to CL psychiatry. There is now a much wider recognition of the high prevalence of psychiatric and physical comorbidity and how this influences consultation frequency, service utilisation, treatment adherence, the physical prognosis and probably the overall cost as well. The relationship between physical disease and mental disorder is influenced by biological factors contributing to psychological change in physical disease, psychological factors in physical disease, social factors and comorbidity. There has also been recognition of the high prevalence of non-organic complaints among general medical patients as well as an awareness of the high costs of investigating these patients, which has led to a search for better ways to manage this group of patients.

Collaboration between general medical and psychiatric staff is essential. Psychological treatment and psychotropic medication can be effective. Mental capacity is an important and sometimes complex issue.