This study evaluates the effects of psychological and pharmacological treatment of regular users of cannabis and psychostimulants in a treatment center (Kfar Izun) in Israel. The participants will undergo psychological evaluation before and during treatment and follow up at 4 months. Ten participants will undergo brain imaging of the dopamine receptor D2 in order to evaluate the effects of treatment on dopamine turnover in the brain. A control group of psychiatric in-patients undergoing treatment for psychiatric illness with be recruited from Geha Hospital in Israel. It is predicted that successful treatment of regular users of cannabis will be resulted in improvement in anxiety, depression and psychotic symptoms as well as in upregulation of dopamine turnover in participants that will undergo brain imaging.

There is a significant number of cannabis and psychostimulant users that experience psychotic episodes and require psychiatric treatment. This study evaluates the effects of psychological and pharmacological treatment of regular users of cannabis and psychostimulants in a treatment center (Kfar Izun) in Israel. The participants will undergo psychological evaluation before and during treatment and follow up at 4 months. Ten participants will undergo brain imaging of the dopamine receptor D2 using [I123] IBZM in Single Photon Emitted Tomography (SPECT) before and after treatment in order to evaluate the effects of treatment on dopamine turnover in the brain. A control group of psychiatric in-patients undergoing treatment for psychiatric illness with be recruited from Geha Hospital in Israel.

Inclusion Criteria:

• cannabis dependence with or without history of psychosis.

Exclusion Criteria:

• pregnant women
• under 18
• neurological damage
• HIV positive
• dependence on other drugs such as heroin
• cocaine or alcohol