Alcohol and substance use by patients with psychosis presenting to an emergency department: changing patterns.

Objectives: The aim of this study was to determine the incidence of alcohol and other substance use in patients presenting to an emergency department with acute psychiatric illnesses and to clarify the role of urine drug screens.

Method: This was an unblinded prospective (observational) cohort study incorporating retrospective review of patient medical records, history of alcohol and substance use, results of urine drug screens and blood alcohol concentrations.

Results: Of 196 acute psychotic patients, 104 were diagnosed with schizophrenia and 92 with "other psychosis". Results of urine drug screens were consistent with self-reported use of substances and only identified an additional 5% of substance users. Cannabis was the commonest illicit substance used by both groups of patients, followed by psychostimulants, mainly amphetamines. Younger males were more likely to use psychostimulants and to present with violence.

Conclusions: Patients with co-existing mental health problems and substance use present a major problem for our emergency departments. Cannabis was the most common substance used. Youth, male gender and psychostimulant use are associated with violent presentations. A comprehensive history of alcohol and substance use is important to implement appropriate dual diagnosis treatment. Urine drug screening is recommended for patients who do not admit to substance use.