Methamphetamine substance use is common worldwide. No approved pharmacologic treatments for methamphetamine dependence exist. paliperidone are Second generation antipsychotics，and have effects of blocking dopamine2(D2) and 5-hydroxytryptamine 2A(5-HT) receptors neurotransmitters.To determine whether mirtazapine would reduce methamphetamine use among methamphetamine addicts.

Methods:A Multiple-Center, Randomized, Double-Blind.

Inclusion Criteria:

• Men and women aged 18 years to 60 years
• Met the Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) criteria for METH dependence with psychosis
• Completing inpatient METH detoxification (≤30 days) with psychotic symptoms disappeared
• Beoff any anti-psychotic medication for 7 days after discharging from hospital were enrolled at clinical site
• Participants were interesting in reducing or stopping METH use
• Every patient also had a significant other (eg., spouse or relative) who supervised their compliance with the visit schedule and study procedures
• Women of childbearing potential agreed to use contraception during the study.

Exclusion criteria:

• Pregnancy or breastfeeding;
• Significant medical conditions (eg., acute renal failure, endocarditis, and tuberculosis); hepatic failure; past or present history of an AIDS-indicator disease; active hepatitis or aspartate amino transferase or alanine aminotransferase more than three times the upper limit of normal
• Known intolerance or hypersensitivity to paliperidone ER; other psychosis; present dependence on substances other than METH or poly-substance abuse.