Effects of Metformin on Spatial and Verbal Memory in Children with ASD and Overweight Associated with Atypical Antipsychotic Use.

OBJECTIVES: Studies in humans and rodents suggest that metformin, a medicine typically used to treat type 2 diabetes, may have beneficial effects on memory. We sought to determine whether metformin improved spatial or verbal memory in children with autism spectrum disorder (ASD) and overweight associated with atypical antipsychotic use. METHODS: We studied the effects of metformin (Riomet®) concentrate on spatial and verbal memory in 51 youth with ASD, ages 6 through 17 years, who were taking atypical antipsychotic medications, had gained significant weight, and were enrolled in a trial of metformin for weight management. Phase 1 was a 16-week, randomized, double-blind, placebo-controlled, parallel-group comparison of metformin (500-850 mg given twice a day) versus placebo. During Phase 2, all participants took open-label metformin from week 17 through week 32. We assessed spatial and verbal memory using the Neuropsychological Assessment 2nd Edition (NEPSY-II) and a modified children's verbal learning task. RESULTS: No measures differed between participants randomized to metformin versus placebo, at either 16 or 32 weeks, after adjustment for multiple comparisons. Sixteen-week change in memory for spatial location on the NEPSY-II was nominally better among participants randomized to placebo. However, patterns of treatment response across all measures revealed no systematic differences in performance, suggesting that metformin had no effect on spatial or verbal memory in these children. CONCLUSIONS: Although further study is needed to support these null effects, the overall impression is that metformin does not affect memory in overweight youth with ASD who were taking atypical antipsychotic medications.

A Randomized, Placebo-Controlled Trial of Metformin for the Treatment of Overweight Induced by Antipsychotic Medication in Young People With Autism Spectrum Disorder: Open-Label Extension.

OBJECTIVE: A previous study reported on a 16-week placebo-controlled, randomized clinical trial (RCT) of metformin for weight stabilization in 61 children and adolescents 6 to 17 years old with autism spectrum disorder who were prescribed atypical antipsychotics. The present study describes the results of a 16-week open-label extension. METHOD: Fifty-two participants from the acute trial (85%) entered the extension; 22 had been on metformin during the initial RCT and 30 had been on placebo. Participants were re-titrated to 500 mg twice a day (6- to 9-year-olds) or 850 mg twice a day (10- to 17-year-olds) during the open-label extension. Primary outcome measure was change in body mass index (BMI) z-score after 16 weeks; secondary outcomes were change in additional body composition and metabolic parameters. RESULTS: After 16 weeks of open-label treatment, participants initially taking placebo during the RCT had lower BMI z-scores (mean 16-week change -0.10, p = .004). Statistically significant improvements also were noted in secondary body composition measures (weight z-score and BMI and weight percentile) but not in metabolic variables. Participants who initially had been taking metformin during the 16-week RCT maintained prior decreases in BMI z-scores but did not have additional weight loss. Three participants discontinued treatment because of an adverse event. No significant changes were noted on metabolic measures, although the decrease in hemoglobin A1c was large (∼1 mmol) and consistent across the acute and open-label phases. CONCLUSION: Metformin can be effective for decreasing weight gain associated with atypical antipsychotic use and maintaining prior improvement in children and adolescents with autism spectrum disorder. Clinical trial registration information-Treatment of Overweight Induced by Antipsychotic Medication in Young People With Autism Spectrum Disorders (ASD); http://clinicaltrials.gov/; NCT01825798.

Metformin for Treatment of Overweight Induced by Atypical Antipsychotic Medication in Young People With Autism Spectrum Disorder: A Randomized Clinical Trial.

IMPORTANCE: Atypical antipsychotic medications are indicated for the treatment of irritability and agitation symptoms in children with autism spectrum disorder (ASD). Unfortunately, these medications are associated with weight gain and metabolic complications that are especially troubling in children and with long-term use. OBJECTIVE: To evaluate the efficacy of metformin for weight gain associated with atypical antipsychotic medications in children and adolescents with ASD (defined in the protocol as DSM-IV diagnosis of autistic disorder, Asperger disorder, or pervasive developmental disorder not otherwise specified), aged 6 to 17 years. DESIGN, SETTING, AND PARTICIPANTS: A 16-week, double-blind, placebo-controlled, randomized clinical trial was conducted at 4 centers in Toronto, Ontario, Canada; Columbus, Ohio; Pittsburgh, Pennsylvania; and Nashville, Tennessee. In all, 209 potential participants were screened by telephone, 69 individuals provided consent, and 61 participants were randomized to receive metformin or placebo between April 26, 2013, and June 24, 2015. INTERVENTIONS: Metformin or matching placebo titrated up to 500 mg twice daily for children aged 6 to 9 years and 850 mg twice daily for those 10 to 17 years. MAIN OUTCOMES AND MEASURES: The primary outcome measure was change in body mass index (BMI) z score during 16 weeks of treatment. Secondary outcomes included changes in additional body composition and metabolic variables. Safety, tolerability, and efficacy analyses all used a modified intent-to-treat sample comprising all participants who received at least 1 dose of medication. RESULTS: Of the 61 randomized participants, 60 participants initiated treatment (45 [75%] male; mean [SD] age, 12.8 [2.7] years). Metformin reduced BMI z scores from baseline to week 16 significantly more than placebo (difference in 16-week change scores vs placebo, -0.10 [95% CI, -0.16 to -0.04]; P = .003). Statistically significant improvements were also noted in secondary body composition measures (raw BMI, -0.95 [95% CI, -1.46 to -0.45] and raw weight, -2.73 [95% CI, -4.04 to -1.43]) but not in metabolic variables. Overall, metformin was well tolerated. Five participants in the metformin group discontinued treatment owing to adverse events (agitation, 4; sedation, 1). Participants receiving metformin vs placebo experienced gastrointestinal adverse events during a significantly higher percentage of treatment days (25.1% vs 6.8%; P = .005). CONCLUSIONS AND RELEVANCE: Metformin may be effective in decreasing weight gain associated with atypical antipsychotic use and is well tolerated by children and adolescents with ASD. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01825798.