Increased Release of Dopamine in the Striata of Young Adults With Hearing Impairment and Its Relevance for the Social Defeat Hypothesis of Schizophrenia

IMPORTANCE: An increased risk for psychosis is observed in people with hearing impairment. According to the social defeat hypothesis, the long-term experience of exclusion leads to enhanced baseline activity and/or sensitization of the dopamine system and puts the individual at increased risk for psychosis. OBJECTIVE: To investigate whether young adults with severe hearing impairment (SHI) experience more feelings of social defeat, show greater dopamine release in response to dexamphetamine, and report a stronger subjective reaction to this substance than normal-hearing young adults and to examine whether dopamine release is associated with both self-reported social exclusion and dexamphetamine-induced psychotic experiences. DESIGN, SETTING, AND PARTICIPANTS: A sample of 19 participants with SHI and 19 smoking-, age-, and sex-matched healthy controls underwent single-photon emission computed tomography with iodine 123–labeled iodobenzamide as a radiotracer before and after an amphetamine challenge at an academic hospital. EXPOSURES: Dexamphetamine sulfate (0.3 mg/kg) administered intravenously. MAIN OUTCOMES AND MEASURES: Baseline D2/3 receptor binding and endogenous dopamine release. RESULTS: The participants with SHI reported experiencing more feelings of social defeat (U = 109, z = −2.09, P = .04) and loneliness (U = 87.5, z = −2.72, P =