This is an individually randomized, sham controlled (tDCS), assessor blinded 2×2 factorial clinical trial comparing: (1) aerobic exercise vs stretching/education control and (2) active vs sham prefrontal tDCS. The factorial design enables estimation of the main effects of exercise and tDCS and their interaction (synergy/antagonism) in one trial.
Participants with treatment resistant schizophrenia (TRS) will complete 18 sessions over 6 weeks (3 sessions/week). Each session includes tDCS (active or sham) during the physical activity condition (aerobic exercise or stretching/education) to standardize timing and contact. Evidence suggests exercise associated cognitive gains relate to intervention dose and supervision. Noninvasive brain stimulation outcomes may vary with stimulation dose parameters, supporting a standardized protocol.
Cognition will be assessed using the MCCB, which evaluates seven cognitive domains relevant to schizophrenia and yields an Overall Composite T score. The primary endpoint is Week 6 (end of intervention), with durability assessed at 3 months post intervention (Week 18).
