This continuing education manual provides an integrative examination of behavioral health and mental health as overlapping yet distinct fields within psychological science and clinical practice. It covers historical development, conceptual models such as biopsychosocial and cognitive-behavioral frameworks, empirical research findings, severity spectrum of mental health conditions, stress response mechanisms, system-level influences, and clinical implications for licensed psychologists. The manual also discusses future challenges and innovations, including precision mental health, digital interventions, and transdiagnostic approaches, to support evidence-informed, culturally responsive psychological practice.