The significant challenges to their daily functioning. The study investigated medication adherence, self-control on and psychological well-being among psychiatric outpatients in selected tertiary health institutions in Benue State Nigeria. The study employed a cross-sectional survey design where two hundred and twenty-five (225) psychiatric outpatients; 125 (55.6%) males and 100 (44.4%) females were sampled for the study with the mean age of 39 years.

Four hypotheses were formulated and tested using linear regression,hayes process macro mediation analysisand standard multiple regression. The findings indicated that there was a significant influence of medication adherence on psychological well-being among psychiatric outpatients in selected tertiary health institutions in Benue State Nigeria. The second finding indicated a significant positive influence of selfcontrol on psychological well-being among psychiatric outpatients in selected tertiary health institutions in Benue State Nigeria. The third finding showed that self-control significantly mediated the relationship between medication adherence andpsychological well-being. The fourth finding revealed there is statistically significant joint influence of medication adherence and self-control on psychological wellbeing among psychiatric outpatients in selected tertiary health institutions in Benue State Nigeria.

It was concluded that medication adherence and self-control are independent and joint significant influencers of psychological wellbeing among psychiatric outpatients in selected tertiary health institutions in Benue State Nigeria. The study recommended that tertiary health institutions should employ integrated intervention approach with multidisciplinary programmes that concurrently address medication adherence and self-control enhancement, fostering synergistic effects on patients'

psychological wellbeing.