Craving is a core feature of heroin use disorder. Craving for heroin is a conscious cognitive process. Recently, implicit (i.e., an implicit attitude toward heroin use) cognitive processes have been thought to be precursors of cravings. This study aimed to explore the associations of craving and implicit attitude toward heroin use with the level of heroin use disorder and adherence to methadone maintenance treatment (MMT). This study recruited 213 intravenous heroin users (196 males and 17 females) from MMT clinics of two hospitals. The mean age of participants was 42.3 years. They provided details of their severity of heroin use disorder and craving for heroin via questionnaires and also completed a computerized test to assess implicit attitude toward heroin use. The relationships between implicit attitude, craving, age, heroin use disorder, and MMT adherence were examined using path analysis. Craving was positively related to heroin use disorder (beta = 0.4). Implicit attitude directly and indirectly positively contributed to heroin use disorder (betas: 0.1 and 0.3). Craving was positively related to MMT adherence (beta: 0.2), whereas implicit attitude had an indirect effect on MMT adherence (beta: 0.03). Age was negatively associated with craving but was not associated with implicit attitude toward heroin. Methadone dosage was negatively associated with craving. Craving is significantly associated with the levels of heroin use disorder and MMT adherence. Meanwhile, craving mediates the relationship between implicit attitude and heroin use disorder, as well as MMT adherence. Implicit attitude also contributes to the level of heroin use disorder directly. For reducing craving, adequate dosage may be necessary.
Keywords: Implicit attitude; MMT and opioids; attendance; craving.