Depression in Opioid Use Disorder: A Tripartite Psychopathological Model for Dual Disorders.

Depressive symptoms are highly prevalent among individuals with substance use disorders, particularly opioid use disorder (OUD), yet their clinical meaning is often difficult to determine. In routine practice, these symptoms are commonly interpreted within a binary framework, either as manifestations of an independent mood disorder or as substance-induced states related to intoxication, withdrawal, or early abstinence. Although clinically useful, this distinction may not fully capture a third configuration in which depressive psychopathology emerges within the chronic addictive process itself. This Perspective proposes a tripartite model of depressive states in OUD informed primarily by clinical and dimensional studies conducted in populations with heroin use disorder. First, substance-induced depression refers to mood symptoms temporally linked to the acute or subacute pharmacological effects of substances and generally expected to improve with stabilization or sustained abstinence. Second, an independent mood disorder may coexist with OUD, with particular attention warranted for bipolar-spectrum presentations characterized by affective instability, cyclothymic or irritable temperaments, mixed features, and mood-related patterns of substance use. Third, addiction-related depression describes a persistent depressive configuration associated with reward dysregulation, hypophoria, motivational depletion, cognitive inefficiency, and the Worthlessness/Being Trapped dimension identified primarily in dimensional studies of heroin use disorder. These configurations should not be regarded as rigid or mutually exclusive categories, but as longitudinal clinical formulations that may predominate at different stages of the addictive trajectory. Distinguishing among them may improve diagnostic clarity and support a hierarchical clinical approach in which stabilization of OUD is generally an initial therapeutic priority, while antidepressant and mood-stabilizing interventions are guided by symptom severity, temporal course, psychopathological organization, and evidence of an independent mood disorder.