The proposed protocol is a double-blind, placebo-controlled inpatient and outpatient study,looking at the clinical treatment of cannabis use disorder.

The treatment study is a total of 12 weeks. There will be two options offered to participants for week 1 of the treatment study. 1) Patient will go inpatient for 5 nights and after discharge from the inpatient phase will complete the 11-weeks of outpatient treatment or 2) patients who cannot complete the inpatient phase due to work or other obligations will complete the treatment 12-week study outpatient. 80 patients seeking treatment for cannabis use disorder will be enrolled into either the inpatient/outpatient or only outpatient study. This combined design will provide a comprehensive understanding of clonazepam's effects on individuals with cannabis use disorder across a range of outcome measures while also testing the medication's ability to prevent relapse in cannabis-abstinent patients.

Patients seeking treatment for Cannabis Use Disorder (CUD) will be enrolled into an inpatient laboratory for 5 nights, where they will be initiated on medication and be assessed for the influence of clonazepam (or placebo) on (1) cannabis withdrawal (mood, sleep, cannabis craving, food intake), ratings associated with medication abuse liability, cognitive performance, and (2) relapse to cannabis use after patients (now abstinent from cannabis) leave the inpatient setting maintained on clonazepam (or placebo) for 8 weeks (with a 4-week, medication-free follow up). This combined design will provide a comprehensive understanding of clonazepam's effects on individuals with cannabis use disorder across a range of outcome measures (safety, abuse liability, withdrawal symptoms) while also testing the medication's ability to prevent relapse in cannabis-abstinent patients. Patient's who are unable to complete the inpatient approach will complete the 12 week trial as an outpatient only.

Inclusion Criteria:

• Meets DSM 5 criteria for CUD of at least moderate severity (≥ 4 symptoms) and is seeking treatment for cannabis use.
• Reports using cannabis a minimum of 5 days per week over the past 28 days and have positive urine test for THC on the day of study entry
• 18-65 years of age

Exclusion Criteria:

• Individuals with a lifetime DSM-5 diagnosis of schizophrenia, schizoaffective disorder, or bipolar disorder
• Individuals meeting current DSM-5 criteria for any other psychiatric disorder that may, according to the investigator's judgment, require either pharmacological or non-pharmacological intervention over the course of the study. Individuals who are currently stable on a psychotropic medication for at least 3 months may be included if in the investigator's opinion the psychotropic medication is compatible with the study medication (clonazepam). CNS depressants (e.g., benzodiazepines, opioids, adrenergic agonists) and cyp3A4 inhibitors (ketoconazole, some antipsychotics & anticonvulsants) will be exclusionary.
• Known history of allergy, intolerance or hypersensitivity to benzodiazepines
• Episodic or chronic use of benzodiazepines
• Pregnancy, lactation, or failure to use adequate contraceptive methods (condoms, diaphragm, birth control pill, IUD) in female patients who are currently engaging in sexual activity with men.
• Unstable medical conditions, such as poorly controlled hypertension, which might make participation hazardous
• Participants with a current DSM-5 diagnosis of an alcohol of substance use disorder (abuse or dependence) other than cannabis or nicotine use disorder
• Are legally mandated to participate in a substance use disorder treatment program
• Increased risk for suicide
• Current parole or probation
• Recent history of significant violent behavior
• History of current of past diagnosis of glaucoma
• History of benzodiazepine or other sedative hypnotic use disorder

Length of participant's participation, up to 12 weeks