insufficient recrutement in the study

Abuse of psychoactive substances is a behavior belonging to the field of risk behaviors that begins and takes place during adolescence. These risk behaviors are a major public health problem in France and worldwide.

Cannabis is the first illicit drug consumed by adolescents in France. His experimentation progresses rapidly between 11 and 17 years. The relationship between cannabis use and mental health has been shown by several studies. In particular Attention Deficit Hyperactivity Disorder (ADHD), characterized by attention deficit, impulsivity and disabling motor hyperactivity and beginning before 12 years of age (DSM-5), is a major risk factor for the consumption of cannabis. ADHD is a common condition (9% of children and 5% of adults), but often undiagnosed or untreated. It has been shown that the treatment of ADHD in childhood protects the consumption of psychoactive products during adolescence or adulthood. However, to our knowledge there is no study showing that treatment with methylphenidate in an ADHD patient - not treated - but already a cannabis user, was a positive prognostic factor in the decrease in cannabis use.

Abuse of psychoactive substances is a behavior belonging to the field of risk behaviors that begins and takes place during adolescence. These risk behaviors are a major public health problem in France and worldwide.

Cannabis is the first illicit drug consumed by adolescents in France. His experimentation progresses rapidly between 11 and 17 years. The relationship between cannabis use and mental health has been shown by several studies. In particular Attention Deficit Hyperactivity Disorder (ADHD), characterized by attention deficit, impulsivity and disabling motor hyperactivity and beginning before 12 years of age (DSM-5), is a major risk factor for the consumption of cannabis. ADHD is a common condition (9% of children and 5% of adults), but often undiagnosed or untreated. It has been shown that the treatment of ADHD in childhood protects against the use of cannabis during adolescence or adulthood. However, there is no study showing that treatment with methylphenidate in an ADHD patient - not treated - but already a cannabis user, was a positive prognostic factor in the decrease in cannabis use.

Hypothesis: The hypothesis of this study is that patients diagnosed with ADHD and cannabis-treated patients treated with methylphenidate will decrease their number of days of cannabis use compared to ADHD patients receiving placebo.

Originality and Innovative There is no study showing that treatment with methylphenidate in an ADHD patient - not treated - but already a problematic cannabis user, was a positive prognostic factor in decreasing cannabis use.

Moreover, there is not enough team in addiction trained in the detection of attention deficit disorder which is now recognized as a factor of vulnerability for the development of addictions. This project is the opportunity for a training in the detection of the ADHD in the adolescent and the young adult of the professionals of the addiction and the setting up of a treatment by Methylphenidate as well as its handling.

Inclusion Criteria:

• Age ≥ 12 and ≤ 25 years;
• Patients from 25 to 120 kg
• ADHD diagnosed according to the criteria of the DSM - V
• ADHD-RS-IV ≥ 28 test score;
• Without medication by methylphenidate for at least 6 months;
• Lack of psychiatries co-morbidities associated with a contraindication to treatment with methylphenidate (confirmed by MINI or MINI Kid); absence of BPD (tracked by the self-administered questionnaire MSI - BPD).
• Cannabis dependence objectified by a positive qualitative urinary dosage and a score ≥ 7 to CAST questionnaire;
• Consent of parents (child/teenager < 18 years) or young age if ≥ 18 years - patients of childbearing age agreeing to use a contraceptive method during the duration of the test

Exclusion Criteria:

Patients placed in child welfare (ASE).

• Pregnant patients or nursing
• No affiliation to a scheme of social security (beneficiary or beneficiary)
• Contraindications to treatment with methylphenidate :known hypersensitivity to methylphenidate or any of the excipients, glaucoma, pheochromocytoma,treatment by non selective irreversible inhibitors of the mono-amine oxidase (MAOI) and also for at least 14 days after stopping treatment with an MAOI because of the risk of hypertensive thrust,Treatment by other sympathomimetic indirect or sympathomimetic (oral and/or nasal way) alpha,Hyperthyroidism or wrong,diagnosis or history of severe depression, anorexia nervosa or disorders anorexia, suicidal tendencies, mood disorders, psychotic symptoms, mania, schizophrenia, psychopathic personality disorder, or limit (borderline), occlusal,diagnosis or history (affective) bipolar disorder severe (for type 1) and episodic (and poorly controlled), pre-existing cardiovascular disorders including severe hypertension, heart failure, pad angina, congenital heart disease with hemodynamic impact; cardiomyopathy, myocardial infarction, arrhythmias and channelopathies (disorders caused by a dysfunction of ion channels) that can potentially be life-threatening, pre-existence of disorders, stroke, cerebral aneurysm, vascular abnormalities, including stroke or Vasculitis and major Patient protected by law.