Could a Parkinson's drug fix antipsychotic side effects?

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

Inclusion Criteria: 1. Adult males and females, 18-65 years of age, diagnosed with schizophrenia 2. Female participants must test negative for pregnancy at the time of enrollment based on a urine pregnancy test and agree to use a reliable method of birth control (e.g., oral contraceptives, birth control diaphragms with contraceptive jelly, cervical caps with contraceptive jelly, condoms with contraceptive foam, intrauterine devices, partner with vasectomy, or abstinence) until the study is complete. 3. Be treated with FDA-approved second generation antipsychotic medication for at least 3 months, with no change in dose in the 1 month prior to enrollment. 4. Either fasting glucose of 100 to 125 mg/dL inclusive and/or an A1C in the range between 5.7-6.4% 5. Body mass index at least 30 kg/m2 at screening visit. 6. Subject must be willing to provide contact information for a close family member or friend that will contact the study team if the participant exhibits signs of psychological deterioration 7. Subject's primary mental health provider concurs that study enrollment is acceptable Exclusion Criteria: 1. History of documented APD non-adherence in prior 3 months. 2. Historical or current diagnosis of diabetes mellitus (type 1, type 2, or other) 3. Pregnant or breast feeding. Women of child-bearing potential must be surgically-sterile or using reliable methods of birth control. 4. May not have used oral or parenteral systemic corticosteroids within 3 months prior to study enrollment or have expected use during the course of the study. The use of either inhaled or topical corticosteroids are not exclusion criteria. 5. May not be taking any antidiabetic/antihyperglycemic medications (e.g., metformin, sulfonylureas, thiazolidinediones, insulin, DPP-IV inhibitors, SGLT-2 inhibitors, etc.) currently or within 4 months prior to study enrollment. 6. May not be taking any of the following cytochrome P450 3A4 (CYP3A4) inhibitors: protease inhibitors (atazanavir, boceprevir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, telaprevir); certain antibiotics/antifungals (clarithromycin, erythromycin, telithromycin, chloramphenicol, ciprofloxacin, fluconazole, itraconazole, ketoconazole, posaconazole, voriconazole); nefazodone; aprepitant; imatinib; certain calcium channel blockers (diltiazem, verapamil); Valerian; or grapefruit/grapefruit juice. 7. May not be taking or have sensitivity to any dopamine agonist medications (e.g., bromocriptine, cabergoline, pramipexole,ropinirole, rotigotine, etc.) currently or within 3 months prior to study enrollment. 8. May not be taking or have any sensitivity to any other ergot alkaloids (e.g., dihydroergotamine, ergotamine) 9. PANSS score \>90, which is equivalent to "moderately ill" 10. Any current hepatic or renal disease 11. Any documented history of violent behavior 12. Diagnosis of Alcohol use disorder or substance use disorder in the past 12 months unless meeting remission criteria as defined by MINI.