Can a diabetes drug beat metformin for antipsychotic weight gain?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion criteria: * Patients aged ≥16 years * Diagnosis according to DSM-5 criteria, including: Schizophrenia spectrum and other psychotic disorders, as summarized in the DSM-5 chapter Schizophrenia Spectrum and Other Psychotic Disorders, excluding: Substance/medication-induced psychotic disorder Psychotic disorder due to another medical condition Catatonia associated with another mental disorder Catatonic disorder due to another medical condition Unspecified catatonia Bipolar and related disorders, as summarized in the DSM-5 chapter Bipolar and Related Disorders Depressive disorders, as summarized in the DSM-5 chapter Depressive Disorders Obsessive-compulsive and related disorders, as summarized in the DSM-5 chapter Obsessive-Compulsive and Related Disorders Other psychiatric conditions for which antipsychotic treatment is clinically indicated, as judged by the investigator Other conditions where antipsychotics are indicated * Receiving stable antipsychotic treatment for ≥3 months prior to enrollment * Evidence of antipsychotic-induced weight gain (AiWG), defined as: 1. ≥7% increase in body weight from baseline following initiation of antipsychotic treatment, or 2. BMI \>25 kg/m² with clinically established antipsychotic-associated weight gain * Able to understand and comply with study procedures, as judged by the investigator * Able to provide written informed consent. For participants aged 16-17 years, assent and/or guardian consent will be obtained according to local ethics committee requirements. Exclusion criteria: * Diabetes mellitus * Diagnosed patients of polycystic ovarian syndrome (PCOS) * Renal impairment defined as estimated glomerular filtration rate (eGFR \<45 mL/min/1.73 m²) * Significant hepatic disease or other serious or unstable medical conditions that, in the opinion of the investigator, would make participation unsafe * Pregnant or breastfeeding females * Current use of metformin, dapagliflozin, or another sodium-glucose cotransporter 2 inhibitor. * Use of weight-loss medications or participation in structured weight-loss programs within the past 3 months * Recurrent genitourinary infections (if dapagliflozin is used) * Use of non-antipsychotic medications known to cause clinically significant weight gain, including but not limited to selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), mirtazapine, tricyclic antidepressants, valproate, lithium, corticosteroids, sedating antihistamines, or other medications as judged by the investigator * Unstable psychiatric condition or active substance use disorder that may impair the ability to adhere to study procedures, as judged by the investigator