Lamotrigine for Ketamine Dependence Trial

Inclusion Criteria: 1. Current users of ketamine, including having a ketamine-positive urine 2. Meeting DSM-5 criteria for ketamine use disorder 3. Age between 18 to 65 years old 4. Women of childbearing age must have a negative pregnancy test to enroll in this study, agree to monthly pregnancy testing, and agree to use appropriate forms of birth control for the duration of the study. Exclusion Criteria: 1. Significant medical conditions such as abnormal liver function or renal function confirmed by laboratory tests 2. Hypertension 3. A current cardiac condition or high risk of cardiovascular disease 4. Seizure disorders 5. Any another significant underlying medical condition which would contraindicate lamotrigine treatment 6. Meeting DSM-IV psychiatric classifications for schizophrenia, bipolar disorder, or other psychotic disorders 7. Meeting DSM-IV psychiatric classifications for substance use disorder other than ketamine within three month except tobacco or caffeine. 8. Exhibiting current suicidality or homicidality 9. Pregnant women, lactating women or women who are planning to be pregnant.