Medium secure units were designed to treat patients for up to three years, but some patients spend longer in acute medium secure settings which in general do not have a 'longer term focus'. The aim of this investigation was to assess and describe the needs of these patients. A survey questionnaire was designed and sent to responsible clinicians who had patients admitted at least five years previously to the Three Bridges Medium Secure Unit (males) in West London. Carer ratings using the Camberwell Assessment of Need: forensic version (CAN-FOR) were completed by the primary nurse for each patient, complementing the survey questionnaire. Of 122 medium secure male patients 25 (21%) had been admitted at least five years before. We found high levels of co-morbidity and treatment resistance. The CAN-FOR revealed two groups, one with chronic challenging behaviour, treatment-resistant mental illness and need for a high level of support, and another more able group not needing as much support but with a dependency on the hospital. It is considered here whether certain groups would benefit from a different approach or setting.