Most mentally ill offenders within institutions are treated with psychotropic medication, particularly when the patient is floridly psychotic or severely depressed. Britain's Regional Secure Units are based on a multidisciplinary philosophy, in which a combination of neurological, psychiatric, psychological, and sociological factors are considered for the patient's management, treatment, and rehabilitation. Psychological treatments, such as cognitive-behavioral techniques, are unlikely to work with mentally ill patients while they are in the acute stage of their illness. Once the patient's acute symptoms have subsided, psychological techniques may be appropriately implemented. One of the major problems highlighted in this paper is the lack of motivation among may patients to participate in treatment programs. Patients with a long-standing history of mental illness are the most difficult to motivate. The final section of this paper discusses the contribution that psychologists can make to the treatment of a particular offender group, i.e., compulsive shoplifters. 1 table and 25 references