Three cognitive assessments, Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Loewenstein Occupational Therapy Cognitive Assessment (LOTCA), were used to assess the cognitive abilities among methamphetamine-dependents. According to the results, MMSE showed that there were 9 methamphetamine-dependent patients having cognitive impairment with the cut-off point below 22. Meanwhile, 55 patients were considered to have cognitive dysfunction when assessed with MoCA