Dextromethorphan, Memantine Monotherapy, or Combined Use of Dextromethorphan and Memantine in Amphetamine Addiction

Treatment Efficacy in Dextromethorphan, Memantine Monotherapy, or Combined Use of Dextromethorphan and Memantine in Patients With Amphetamine-type Stimulants Use Disorder

The investigators will conducted a randomized double-blind placebo-controlled study to investigate the treatment outcomes of add-on low dose dextromethorphan (DM), memantine (MM), or dextromethorphan and memantine combination (DM+MM) in amphetamine-type stimulants use disorder patients.

The investigators will conducted a randomized double-blind placebo-controlled study to investigate the treatment outcomes of add-on low dose dextromethorphan (60mg/day, DM), memantine (5 mg/day, MM), or dextromethorphan (60mg/day) and memantine (5mg/day) combination (DM+MM) in amphetamine-type stimulants use disorder patients. The investigators will recruit 120 patients with ATSUD in three years and allocate participants to add-on DM, MM, DM+MM or placebo group in a 1:1:1:1 ratio (participants will also undergo usual psychosocial interventions).The investigators will follow up the participants for 12 weeks and measure the treatment responses, urine drug tests, craving scales and side effects to evaluate the therapeutic effects of add-on DM, MM, or DM+MM. Neuropsychological assessments, tests for inflammatory parameters and neurotrophic factors, and brain functional magnetic resonance imaging (fMRI) will also be evaluated during 12-weeks follow up.

Inclusion Criteria:

1. Signed informed consent by patient or legal representative.
2. Male or female patient aged ≧20 and ≦65 years.
3. A diagnosis of ATSUD according to DSM criteria made by a specialist in psychiatry.
4. Patient or a reliable caregiver can be expected to ensure acceptable compliance and visit attendance for the duration of the study.

Exclusion Criteria:

The presence of any of the following will exclude a patient from study enrollment:

1. Women of childbearing potential, not using adequate contraception as per investigator judgment or not willing to comply with contraception for the duration of the study.
2. Females who are pregnant or lactation.
3. Other major Axis-I DSM-IV diagnosis other than ATSUD, except for tobacco use disorder, ATS induced mood or psychotic disorders.
4. Current evidence of an uncontrolled and/or clinically significant medical condition, e.g., cardiac, hepatic and renal failure that would compromise patient safety or preclude study participation.
5. History of allergy or intolerable side effects of DM or MM.
6. Suicidal attempts or risks during screen or study period.
7. Presence of active infectious or autoimmune disease.