Correll CU, Sikich L, Reeves G, et al. - Researchers sought to examine the efficacy and tolerability of the addition of metformin, the switch to an antipsychotic with lower risk for weight gain, and continued antipsychotic treatment, against the background of healthy lifestyle education (HLE), in youth with severe mental illness and clinically significant antipsychotic-induced weight gain. In the Improving Metabolic Parameters in Antipsychotic Child Treatment (IMPACT), a randomized, parallel group, 24-week clinical trial, enrollment of overweight/obese, psychiatrically stable youth, aged 8-19 years, with a DSM-IV diagnosis of severe mental illness (schizophrenia spectrum disorder, bipolar spectrum disorder or psychotic depression), was done at four US universities. Treatment with a second-generation antipsychotic led to substantial weight gain in all of them. Researchers here randomized 127 participants via the centralized, computer-based randomization system to unmasked treatment groups: metformin (MET); antipsychotic switch (aripiprazole or, if already exposed to that drug, perphenazine or molindone; SWITCH); or continued baseline antipsychotic (CONTROL). All participants received healthy lifestyle education. Forty-nine participants were randomized to MET, 31 to SWITCH, and 47 to CONTROL. Outcomes revealed the achievement of superior weight-related outcomes for both MET and SWITCH when compared with CONTROL, with effect sizes ranging from 0.40 to 0.99, without being different from one another. Data suggest that adding metformin or switching to a lower risk antipsychotic could lead to pediatric antipsychotic-related overweight/obesity. They identified healthy lifestyle education as insufficient to limit ongoing BMI z-score increase.