Objective: Methamphetamine, a highly addictive drug producing manifold effects within users’ bodies, impacts users, families, partners, and the society in many negative ways. Thailand punishes drug use severely, but also offers treatment programs for rehabilitation. This study assessed demographic characteristics and drug use behaviors associated with the psychosocial impacts of methamphetamine use, including direct behavioral effects, psychological and physical symptoms, and domestic violence. Materials and Methods: In this cross-sectional study, 1969 Thai methamphetamine users participating in a treatment program were interviewed using a structured questionnaire. Cluster sampling was implemented: 77 provinces were divided into 8 clusters, representing each area of Thailand. Statistical analysis involved frequency distributions, percentages, mean, SD, χ2, multiple logistic regressions, and odds ratio with 95% confidence interval at a significance level of P <0.05. Results: About 70.40% (n=1386) of participants demonstrated abnormal symptoms, and 24.88% (n=490) had demonstrated domestic violence; younger users had a higher likelihood of demonstrating both. Abnormal symptoms associated with participants’ age group and use duration were statistically significant. χ2 test showed significant differences in indirect behavioral effects, psychological symptoms, and all physical symptoms between use durations of under and over a year. Single participants and those who used methamphetamine once per day had a lower risk (6%) of demonstrating domestic violence; unemployed participants (15%) and young participants (12%) had a greater risk. Conclusions: Treatment programs should provide additional knowledge with regard to harm reduction, dealing with abuse, and reduction of domestic violence. Programs targeting young users should be created.