The primary objective of this study is to evaluate an Integrative Therapy for Adolescent Cannabis Use (TIMCA), integrating elements of Motivational Interviewing (MI), Cognitive Behavioral Therapies (CBT) and an Attachment-Based Intervention (ABI), (IBA),compared to Treatment As Usual (TAU) on cannabis use.

The secondary objectives of the study are:

To assess the effectiveness of the TIMCA, in comparison to the TAU, on: (1) Relationship quality with parents, (2) Relationship quality with closest friend, (3) Emotional regulation strategies, (4) Depressive symptomatology, (5) Anxiety symptomatology, (6) Adherence to therapy

Cannabis is the most used psychoactive substance in the world after tobacco and alcohol, particularly among adolescents and young adults. Cannabis use during adolescence can lead to cognitive, psychological, academic, and social consequences, causing significant distress. In 2019, French adolescents reported one of the highest levels of cannabis experimentation and use (past month) in Europe (5th and 2nd respectively) (Philippon & Spilka, 2020). Regular use of cannabis during adolescence can cause or reinforce psychological suffering in both the young person and those around him/her, and therefore constitutes a major public health issue. Although psychotherapeutic techniques form the basis of treatment for Cannabis Use Disorder (CUD), relapse is common at the follow-up assessment after therapy has ended (Gates et al., 2016; Walther et al., 2016). The literature shows the effectiveness of Motivational Interviewing (MI) on the one hand, and psychotherapies such as Cognitive Behavioral Therapies (CBT) and Multidimensional Family Therapy (MDFT) on the other. The most consistent and coherent evidence supports the combination of CBT and MI to decrease the frequency and severity of cannabis use. As the combination of MI and CBT has proven to be effective with young users, it seems important to add an Attachment-Based Intervention (ABI), as difficulties with interpersonal relationships and emotional regulation are risk factors for the development and maintenance of addiction in adolescents (Fairbairn et al., 2018; Rahioui, 2016).

This randomized, single-blind, two-arm, parallel, multicenter trial postulates that participants in the TIMCA group will have better outcomes than those in the Treatment As Usual (TAU) group in terms of cannabis use, quality of relationship with others, emotional regulation strategies, as well as anxiety-depressive symptomatology (during therapy, at the end of therapy, and at four weeks after the end of therapy).

Inclusion Criteria:

• Aged 14 to 19 years 11 months 29 (or 30) days at the time of the inclusion visit
• Consulting as an outpatient center:
• Fulfilling the criteria for Cannabis Use Disorder (CUD) according to DSM 5 criteria (mild, moderate or severe)
• Fluent in oral and written French
• Benefiting from a social security plan
• Having signed their consent to participate (and their legal representative if applicable).

Exclusion Criteria:

• With an acute psychiatric disorder and/or a psychotropic treatment (a characterized depressive episode, a bipolar disorder, a psychotic disorder)
• With a substance use disorder other than cannabis and tobacco,
• Already engaged in another form of therapy
• Pregnant women at the time of inclusion
• Participants of age subject to a legal protection measure or unable to express their consent