Co-morbid substance dependence is common in patients of secure psychiatric services. Identifying opportunities for intervention, monitoring progress in treatment and assessing risk of relapse are compromised by this group's limited access to illicit substances. This research investigated the validity of the substance use paralleling behaviour (SUPB) framework, which was developed to assist staff in identifying behaviours indicative of substance dependence in controlled environments. Thirty-one patients admitted to the acute units of a secure forensic psychiatric hospital were interviewed and assessed with the Brief Psychiatric Rating Scales, the structured clinical interview for DSM disorders substance use disorders module, and an original questionnaire measuring motivations for drug use and behaviours indicative of substance dependence in a controlled setting (SUPBs). Results showed that patients with a history of substance dependence preceding admission engaged in more SUPBs during hospitalisation than patients without a history of substance dependence. Severity of psychiatric illness was unrelated to the frequency of requests for Pro re nata (PRN) medication and SUPBs. These results provide preliminary support for the SUPB framework and suggest that these behaviours might usefully be considered by staff of secure psychiatric hospitals when planning treatment, measuring progress and ascertaining risk of relapse. Opportunities for clinical application and future research are discussed.