Design paper: The CapOpus trial: A randomized, parallel-group, observer-blinded clinical trial of specialized addiction treatment versus treatment as usual for young patients with cannabis abuse and psychosis

Carsten Hjorthøj¹ , Allan Fohlmann¹ , Anne-Mette Larsen¹ , Mette TR Madsen¹ , Lone Vesterager¹ , Christian Gluud² , Mikkel C Arendt³ and Merete Nordentoft¹

¹Psychiatric Center Bispebjerg, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark

²Center for Clinical Intervention Research, Copenhagen Trial Unit, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark

³Centre for Psychiatric Research, Institute of Clinical Medicine, University of Aarhus, Aarhus, Denmark

author email corresponding author email

Trials 2008, 9:42doi:10.1186/1745-6215-9-42


Published:	11 July 2008

Abstract

Background

A number of studies indicate a link between cannabis-use and psychosis as well as more severe psychosis in those with existing psychotic disorders. There is currently insufficient evidence to decide the optimal way to treat cannabis abuse among patients with psychosis.

Objectives

The major objective for the CapOpus trial is to evaluate the additional effect on cannabis abuse of a specialized addiction treatment program adding group treatment and motivational interviewing to treatment as usual.

Design

The trial is designed as a randomized, parallel-group, observer-blinded clinical trial. Patients are primarily recruited through early-psychosis detection teams, community mental health centers, and assertive community treatment teams. Patients are randomized to one of two treatment arms, both lasting six months: 1) specialized addiction treatment plus treatment as usual or 2) treatment as usual. The specialized addiction treatment is manualized and consists of both individual and group-based motivational interviewing and cognitive behavioral therapy, and incorporates both the family and the case manager of the patient.

The primary outcome measure will be changes in amount of cannabis consumption over time. Other outcome measures will be psychosis symptoms, cognitive functioning, quality of life, social functioning, and cost-benefit analyses.

Trial registration

ClinicalTrials.gov NCT00484302.