The comorbidity of mental illness and substance abuse (dual diagnosis) can complicate both clinical picture and prognosis. It is therefore important to recognise both nosological entities and to treat them simultaneously.

Our main aim was to investigate and describe the characteristics of dual diagnosis patients who were in treatment with a community addiction service, and to assess the completeness of clinical documentation.

We created a data collection tool to measure indices of illicit substance and alcohol use, psychiatric diagnosis, and treatments received for both problems. We included measures of physical health relating to drug and alcohol use. Clinical information was collected from the electronic patient record system.

The audit is ongoing. 498 patients were under the care of the addictions service in February 2012. To date we have identified 72 patients (14.5%) with dual diagnosis. Of this group, 79% of patients were addicted to opiates and 42% were polysubstance users.

The psychiatric diagnosis included mood disorders (29%), anxiety disorders (24%) and psychosis (14%). However 28% had no formal diagnosis recorded, despite receiving treatment for psychiatric conditions.

67% were prescribed methadone. 40% of the patients were receiving medication for their mental illness.

14.5% of our addictions population had a mental health problem. We identified lapses in clinical documentation related to both illnesses. The distinction between addictions and psychiatric services can bring difficulties in communication and care provided. Quality and continuity of care is important and consideration should be given to further development of dual diagnosis services.