A Relation Between Craving Induction and Treatment Response in Deep Transcranial Magnetic Stimulation (dTMS) for Reducing Antipsychotic-induced Weight Gain in Schizophrenia

The underlying causes of antipsychotic-induced weight gain are still unknown. Some research point out that it has something to do with metabolic disturbances and changes in appetite and food intake. With fMRI study, it is reported having dysfunction between prefrontal and insula cortex of its cognitive regulation, interoceptive signals and reward control. dTMS, H4 coil in particular, simultaneously targets prefrontal and insula cortex. Previous study has been deconstrued that dTMS could significantly improve weight gain. Moreover, it is reckoned that TMS has state-dependent effects on brain circuitry, suspected that symptom provocation may be made it more susceptible to modulation which may improve response. Therefore, this study is to explore the efficacy of dTMS on antipsychotic-induced appetite, and whether provoking symptoms can improve dTMS clinical responses.

With regard to investigate this, the investigators will be carried out a randomized single session dTMS, crossover, sham controlled clinical trial. 30 Patients with schizophrenia will be randomly treated with dTMS after food cue induced craving (FCC), dTMS without FCC and sham condition without FCC. Each session has three days intervals for washout. The follow-ups are at the baseline and after each session immediately. The main outcome measures include the change in Food-Cravings Questionnaires state (FCQ-S) score, Visual Analogue Scale (VAS) score, changes in Stop-Signal test (SST) behavioral assessment and the resting-state functional magnetic resonance imaging data.

Inclusion criteria

• Aged between 18-60
• Meeting the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria for schizophrenia, confirmed by the Structured Clinical Interview for DSM-5 (SCID-5).
• Gaining body weight around 7% after intaking antipsychotics within 2 years
• Participants were on a stable medication regimen at the time of enrollment
• Written informed consent was obtained from both the participants and their legally authorized guardians

Exclusion criteria

• Participants who switch antipsychotic drugs (APDs) or require a dose modification exceeding 25% of the baseline dosage during the study period.
• Diagnosed with other mental diseases in accordance with DSM-V
• Comorbid with other severe physiological diseases
• Active suicidal ideation
• A history of alcohol or substance use disorder (or abuse)
• Presence of metal implants or any other conditions contraindicated for magnetic resonance imaging (MRI)
• Presence of intracranial metal or electronic devices, a personal or family history of epilepsy, or any other standard contraindications to deep transcranial magnetic stimulation
• Receipt of regular repetitive transcranial magnetic stimulation (rTMS), electroconvulsive therapy (ECT), or weight-loss interventions within the past month
• Pregnant or lactating women