Psychosis as endogenous dopamine addiction: a scoping review from dopaminergic mechanisms to recovery

Psychosis and addiction are studied in largely separate fields. Both centre on dopaminergic dysregulation, but from different paradigms — aberrant salience and reinforcement learning respectively. These ask different questions: reinforcement learning explains how behaviour is shaped by actual outcomes, whereas aberrant salience describes how stimuli acquire meaning in the absence of any outcome. The two bodies of work rarely cite one another, and the separation reaches into clinical practice: dopamine blockade is the standard treatment for psychosis, while addiction science describes how dampening that same system impairs motivation and the experience of reward — a tension that returns in questions of treatment adherence and recovery. This project holds the registered protocol for a scoping review that maps how far concepts from addiction science — craving, tolerance, sensitization, loss of control, relapse — have been applied to the psychotic state itself. The comparison runs across five domains. Neurobiologically, it concerns the anatomical localization of the dopaminergic processes involved, dopamine supersensitivity psychosis following prolonged D2 blockade, and dopamine dysregulation syndrome in Parkinson's disease — the one place in medicine where addiction to dopamine is already described as a clinical entity. Motivationally, it concerns whether incentive salience, aberrant salience and intrinsic motivation rest on the same dopaminergic system, whether that system can generate defensive as well as approach-related salience, and whether the addiction side of any parallel derives from substance addiction or from behavioral addiction. The review then asks whether the two fields also converge at the clinical, existential and recovery-oriented level: in illness insight, medication adherence, spirituality, and recovery frameworks. The review maps the literature rather than testing a hypothesis. It does originate from one — that psychosis may function as a form of endogenous dopamine addiction — and this is stated openly, because it shaped the search terms. Two countermeasures are built into the design: a dedicated search for criticism of and alternatives to the salience model, and an explicit reporting category for evidence arguing against the hypothesis. Expected outcomes are a map of where and at which level the two fields have already been connected, a conceptual model, and an explicit list of research gaps. Preliminary work suggests that the central finding may be a split rather than a confirmation: the medication-induced and iatrogenic presentations appear to be located in the nucleus accumbens, where incentive salience is localized, while primary psychosis appears to lie outside it. Should that hold, the resemblance to addiction may apply chiefly to treatment-induced forms. A search of PubMed, the Cochrane Library, PROSPERO and OSF Registries on 10 September 2026 identified no comparable published, registered or announced review.