One of the most complex aspects of human behavior is its heterogeneity: individuals experiencing the same situation, identifying with similar personal or cultural identities, in the same developmental stage, or sharing a diagnosis, report different reactions and outcomes. Clinical phenomena in people with the same diagnosis – like major depression or alcohol use disorder – rarely exhibit the exact same symptoms, impairment, and remission trajectories, even after receipt of gold standard, evidence-based treatment. Inter- and intra-individual heterogeneity of this type makes it difficult to identify widely applicable causes and treatment targets for psychopathology and leads to profound mental health disparities worldwide. Precision or personalized medicine offers one potential remedy for this problem by using biopsychosocial factors unique to an individual to develop etiological and treatment models. Increasingly popular, precision medicine is consonant with long-term initiatives in clinical psychology toward dimensional, model-based classification, translational science initiatives, and evidence-based selection and adaptation of behavioral interventions. Despite apparent benefits of individualized approaches, enthusiasm for this movement has outpaced the development of evidence supporting its incremental value and useful tools for its practice worldwide. Broadly, my work aims to develop tools and substantive models of psychopathology and addiction that actualize the benefits of precision medicine (i.e., improve the translation of clinical science evidence to case-specific applications). Toward this aim, I model inter- and intra-individual heterogeneity in clinically relevant biopsychosocial processes emergent in children and families using a person-centered, multimodal, developmental framework. In this talk, I will discuss the methodological scope and substantive and translational implications of my prior research and future directions for global mental health.