Improving quality of life for patients is emerging as a legitimate goal for UK inpatient forensic mental health services. The Lancashire Quality of Life Profile (LQOLP), which has been used widely to measure well-being in community settings, was trialed on an inpatient population being cared for under conditions of high security. Two groups of male patients, drawn from within the same institution but with markedly different clinical conditions, i.e. schizophrenia (N = 47) and personality disorder (N = 48), were interviewed using the LQOLP. Although both groups had been cared for under largely similar environmental conditions over similar lengths of time (9.5 years), the subjective global well-being of the two groups differed systematically as did other objective and subjective well-being measures. However, analysis found that the variations in global well-being could not be attributed readily to factors covered by the interview, including either current mood or personality. Possible reasons for these findings and implications for the use of the LQOLP under conditions of high security are discussed.