The study uses a combined within- and between-subject placebo-controlled study design.
Within subjects phase: After screening, participants will be randomized into two study arms for the fMRI phase of the study. In each study arm, participants will complete a placebo-controlled, within-subject, pharmaco-fMRI paradigm with one of two possible dosages of oxytocin (20 or 40IU) and placebo. Following the fMRI phase of the study, participants will be randomized for the next phase of the study
Between subjects phase: Participants will receive the same dosage of oxytocin the participant received in the fMRI phase, or placebo, twice daily for 3 weeks. Before and after the three weeks of drug administration, participants will be assessed for social functioning, social ability, negative symptoms, and theory of mind. More participants will be randomized to receive chronically administered oxytocin than placebo to maximize the study's power to test the investigators' hypothesis that acute oxytocin-induced increases in right temporo-parietal junction activity will be positively correlated with improvements in social functioning (primary outcome), social ability, negative symptoms, and theory of mind over three weeks of oxytocin administration.
