Hello, Thanks for using healthcaremagic. Schizophrenia is a chronic psychiatry illness and you need to take medicines for long.Most of the antipsychotic medicines for schizophrenia cause weight gain as side effects except few. Aripiprazole and zyprasidone not cause weight gain or even can reduce the weight.As well as typical older antipsychotic cause least weight gain. So you can discuss with above options for your treating doctor to change the medicines if feasible. The best option to reduce weight is exercise and diet control.You need to do regular daily exercises to burn your calorie as well as limited diet without high calorie like avoiding butter,potato and meat and using more fruits and vegetables. These changes will create calorie deficit in your body and burning of fat.In simple language burn more calorie than you take. Running 3km or walking 5 km daily for a month will be suffice to lose 3 kg. Hope I have answered your query, late me know if still any info needed. Regards, Dr. Chintan Solanki