Multiple studies have suggested that autism spectrum disorders seem to increase the risk of overweight and obesity. We examined the pooled prevalence and relative risk of developing overweight or obesity among children with autism spectrum disorders in a systematic review and meta-analysis. We searched PubMed, Scopus, ProQuest, and Web of Science databases and subsequently screened the records to identify studies that reported prevalence of overweight and/or obesity in children with ASD and matched groups of neurotypical children. DerSimonian-Laird random-effects meta-analyses were performed to examine pooled prevalence and relative risk of obesity in children with autism spectrum disorders using the "meta" package in R software. Among children with autism spectrum disorders, the prevalence of obesity was 22.2%. Children with ASD had a 41.1% greater risk (P = .018) of development of obesity. Non-Caucasian race, increasing age, female sex, and living in the United States emerged as positive moderators of the association between autism spectrum disorders and prevalence of overweight or obesity.Autism spectrum disorders seem to increase the risk of childhood obesity.Increased awareness of this association may allow the implementation of early interventions to reduce obesity and prevent potential deterioration of quality-oflife in this population.

We examined the acute effects of l -theanine, caffeine and their combination on sustained attention, inhibitory control and overall cognition in boys with attention deficit hyperactivity disorder (ADHD). l -Theanine (2.5 mg/kg), caffeine (2.0 mg/kg), their combination and a placebo were administered in a randomized four-way repeated-measures crossover with washout, to five boys (8–15 years) with ADHD. Functional magnetic resonance imaging (fMRI) was performed during a Go/NoGo task and a Stop-signal task ~ 1 h post-dose. NIH Cognition Toolbox was administered ~ 2 h post-dose. Treatment vs. placebo effects were examined in multi-level mixed-effects models. l -Theanine improved total cognition composite in NIH Cognition Toolbox (p = 0.040) vs. placebo. Caffeine worsened and l -theanine had a trend of worsening inhibitory control (i.e. increased Stop-signal reaction time; p = 0.031 and p = 0.053 respectively). l -Theanine–caffeine combination improved total cognition composite (p = 0.041), d-prime in the Go/NoGo task (p = 0.033) and showed a trend of improvement of inhibitory control (p = 0.080). l -Theanine–caffeine combination was associated with decreased task-related reactivity of a brain network associated with mind wandering (i.e. default mode network). l -Theanine–caffeine combination may be a potential therapeutic option for ADHD-associated impairments in sustained attention, inhibitory control and overall cognitive performance.

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Objectives Our previous research corroborate the work of others to indicate that L-theanine and caffeine are known to improve sustained attention in healthy adults. The effects of these substances have not been studied in relation to attention deficit hyperactivity disorders (ADHD). We aimed to examine the effects of L-theanine, caffeine and their combination on sustained attention, impulse control and overall cognition in male children with ADHD in a four-way, placebo-controlled repeated measures crossover study. Methods Five male children (8–17) years with ADHD, who have responded to stimulants were recruited via advertisement. L-theanine (2.5 mg/kg body weight), caffeine (2.0 mg/kg body weight), their combination and a placebo were administered in a randomized crossover design on four separate days. Functional magnetic resonance imaging (fMRI) was performed 55 minutes post-dose, while the subjects engaged in a Go/NoGo continuous performance task (CPT) and a stop-signal reaction time (SSRT) task. NIH Cognition Toolbox was administered 110 minutes post-dose. Data were analyzed using two-level regression models constructed using R and FSL software to compare the three treatments vs. the placebo on all measured outcomes. Results L-theanine, caffeine and their combination improved hit rate in CPT (p < 0.001) and total cognition composite in NIH Cognition Toolbox (p < 0.05) compared to placebo. L-theanine and caffeine, when administered alone, increased SSRT (p = 0.007 and p = 0.018 respectively), while the combination decreased SSRT compared to placebo (p = 0.012). L-theanine, caffeine and the combination decreased task-related fMRI reactivity of the default mode network in the brain, which is known to show increased activity during mind wandering. Conclusions L-theanine, caffeine and their combination seem to improve sustained attention and overall cognitive performance in children with ADHD, possibly via decreasing mind wandering during exertion of attention. While L-theanine alone and caffeine alone seem to increase impulsivity, the combination seems to decrease (i.e., improve) impulsivity in children with ADHD. As such, the combination of L-theanine and caffeine may have the potential to be used as a therapeutic and/or dose sparing agent to manage symptoms in children with ADHD. Funding Sources Texas Tech Neuroimaging Institute.