Compulsory drug detention centers (CDDCs) are common throughout Asia. However, medical treatments for substance use disorders, such as opioid agonist treatment (OAT), are generally unavailable in these settings. In this report, we compare the effectiveness of CDDCs with voluntary drug treatment centers (VTCs) offering OAT in Malaysia. Positive urine drug testing (UDT) after release confirmed opioid relapse in both groups. Specifically, we measure the timing of relapse, i.e., we compare when patients that have been discharged from CDDCs and VTCs relapse to opioid.