-This is an open-label trial of long-acting injectable risperidone administered 25mg every 2-weeks for the treatment of methamphetamine (MA) dependence. Participation will last approximately 14 weeks. A total of 20 subjects (veterans and non-veterans) aged 18 to 65 years old who meet DSM-IV criteria for current MA dependence, have a stable address or alternative contact, and expect to be in the Puget Sound area for the length of the study will be enrolled at the Seattle and American Lake Divisions of the VA PSHCS. Exclusionary criteria include: 1) known sensitivity or allergy to risperidone; 2) current treatment with an antipsychotic agent, a mood stabilizer, or CYP 2D6 inhibitor; (3) transaminase levels >5X ULN; (4) albumin levels <3.5g/dl; (5) random serum glucose levels >200mg/dl; (6) diabetes mellitus or history of myocardial infarction; (7) baseline Brief Psychiatric Rating Scale score >72; (8) presence of tardive dyskinesia; (9) Barnes Akathisia Rating Scale global item score >2; (10) Simpson-Angus Scale total score > 0.3; (11) involvement with the legal system that could compromise study participation; (12) pregnancy or nursing; (13) receiving current mental health treatment.