Patient adherence is an integral element of treatment plans and assists in attaining desirable health goals. However, many psychological factors exist, resulting in complex adherence behaviors that challenge healthcare professionals, thus making the work of healthcare providers difficult. This paper critically explores the psychological determinants of patient compliance with medical treatment regimens by conducting a thorough literature review, elaborating on the methods used, and expounding on the results. The main findings highlight the role of belief status, attitude or motivation, self-efficacy, and social help in determining adherence behaviors. Secondly, this work also examines the effects of psychological treatments and several techniques used to elevate patient compliance. The talk revolves around personalized attitudes and mutually shared responsibility between patients and the health care team, allowing optimal medical plan adherence.