This study aimed to explore the extent of association between the classes and patterns (single vs. multiple) of drug use and the psychiatric disorders among recently incarcerated male drug users to help formulate drug policies for correctional facilities and provide adequate treatment for incarcerated drug users. Data were recruited from 414 male first-time incarcerated illicit drug users in one detention center in Taiwan. Their lifetime historical profiles of illicit drug use were then assessed and their associations with current psychiatric disorders were compared with 257 community controls. Heroin and meth/amphetamine were the most commonly used drugs among single and combined users. Heroin users were more likely to exhibit major depression and social phobia; meth/amphetamine users showed more psychotic disorder and antisocial personality disorder than community controls. Multiple drug users were associated with two-thirds of the psychiatric disorders. This study suggests that heroin and meth/amphetamine users require specific treatments, which may effectively address associated psychopathologic conditions. Interventions for mental disorders for some detainees are also recommended.