Sexual Dysregulation After Traumatic Brain Injury and Stroke: A Critical Narrative Review of Neurobiology, Clinical Phenotypes, and Management

Background/Objectives: Acquired brain injury (ABI) can disturb sexual regulation, but the literature does not support a single lesion-to-behavior relationship. This critical narrative review evaluates hypersexuality, sexual disinhibition, and rare acquired paraphilic manifestations after traumatic brain injury (TBI) and stroke, and asks how sparse, heterogeneous evidence can inform proportionate clinical care. Methods: PubMed/MEDLINE, Scopus, and Web of Science were searched up to 6 August 2026. Two reviewers independently screened records and full texts. Evidence appraisal considered methodological quality, directness, and competing explanations. Thirteen English-language case-based publications were assessed, with neurological observations distinguished from pharmacological comparators. Results: Sexual dysfunction is common after ABI, whereas dysregulated sexual behavior is less frequent and poorly quantified. TBI primarily supports a distributed vulnerability model involving diffuse axonal injury and disruption of frontal regulatory connections. Stroke can nominate strategic candidate nodes, but lesion-network effects and clinical context remain decisive. Clinical observations associate inappropriate sexual behavior with broader behavioral difficulties, without establishing a uniform syndrome. Recent guidelines support individualized sexuality care, while contemporary imaging studies strengthen network plausibility without directly establishing sexual-dysregulation mechanisms. Conclusions: A phenotype-first framework separates dysfunction from dysregulation and distinguishes direct clinical evidence from mechanistic extrapolation. Assessment should establish what changed and whether reversible contributors explain the behavior before assigning a persistent phenotype. Management should match the dominant clinical problem, preserve consensual intimacy, and use the least restrictive targeted strategy. Explicit monitoring should determine whether benefit justifies continued treatment. Case-based evidence and language-restricted selection limit generalizability; prospective studies require standardized phenotypes and repeated observation across settings.