In adolescents, mental health problems are frequently associated with substance misuse, even considered a risk factor for alcohol abuse and dependence. This dual diagnosis tends to complicate the patient's treatment and prognosis by increasing, among others, substance use problems, reckless behaviours, relationships and school problems and suicidal thoughts. It is therefore critical to invest time and effort into developing an efficient approach to prevent and reduce substance use problems and offer these children a more global and optimal treatment.

A brief personality-targeted intervention was developed with students of Canadian and English high schools based on four personality factors known to be implicated in the vulnerability to adolescent alcohol misuse (Impulsivity, Anxiety Sensitivity, Negative Thinking and Sensation Seeking) (Conrod et al., 2006,2008, O'Leary-Barrett 2010).

By helping the adolescents to develop better adaptive behaviours, this cognitive-behavioural intervention proved to reduce binge drinking, quantity and frequency of use and substance use problems (Conrod et al., 2006,2011).

The purpose of this study is to assess the impact of this intervention if combined to a regular treatment in a youth psychiatric population.

60 patients aged 14-17 years of a Child and Adolescent psychiatric department will be screened for personality risk with self-report assessments including the Substance Use Risk Profile Scale. Participants will be randomly assigned to a personality matched cognitive-behavioural intervention or a no-intervention control.

The main outcome measures of this study are alcohol and illicit drug outcomes. Secondary measures include mental health symptoms.

Inclusion Criteria:

• Motive for psychiatric consultation
• Able to provide consent from parent/guardian for participation in the study