Although arousal mechanisms have frequently been found to be atypical in ADHD, these findings usually emerged from indirect behavioural measures which give only a limited understanding of arousal dysregulation in this condition. To assess the hypothesis that functioning of the autonomic nervous system (ANS), one component of arousal, is atypical in ADHD, we carried out a systematic review of the literature on 55 studies investigating electro-dermal, heart rate and pupillometry measures under different experimental conditions (resting-state, cognitive tasks and in response to reinforcers or socio-emotional stimuli). Our literature review identified ANS dysfunction in individuals with ADHD, more often in the direction of hypo-arousal than hyper-arousal, particularly at rest and during tasks requiring response regulation and sustained attention. Almost half of the reported findings were null. Stimulant medications increased ANS activity and, in some studies, reinforcers and rewards produced a similar effect, suggesting that ANS function can be modified in ADHD. Further research is needed to assess the influence of comorbid symptoms and to explore methodological parameters that may influence findings.

Aim: To conduct the first systematic review and meta-analysis assessing whether attention-deficit/hyperactivity disorder (ADHD) is associated with disorders of the eye, and/or altered measures of visual function. Method: Based on a pre-registered protocol (PROSPERO: CRD42021256352), we searched PubMed, Web of Knowledge/Science, Ovid Medline, Embase and APA PsycINFO up to 16th November 2021, with no language/type of document restrictions. We included observational studies reporting at least one measure of vision in people of any age meeting DSM/ICD criteria for ADHD and in people without ADHD; or the prevalence of ADHD in people with and without vision disorders. Study quality was assessed with the Appraisal tool for Cross-Sectional Studies (AXIS). Random effects meta-analyses were used for data synthesis. Results: We included 42 studies in the narrative synthesis and 35 studies in the meta-analyses (3,250,905 participants). We found meta-analytic evidence of increased risk of astigmatism (OR = 1.79 [CI: 1.50, 2.14]), hyperopia and hypermetropia (OR = 1.79 [CI: 1.66, 1.94]), strabismus (OR = 1.93 [CI: 1.75, 2.12]), unspecified vision problems (OR = 1.94 [CI: 1.38, 2.73]) and reduced near point of convergence (OR = 5.02 [CI: 1.78, 14.11]); increased lag (Hedge’s g = 0.63 [CI: 0.30, 0.96]) and variability (Hedge’s g = 0.40 [CI: 0.17, 0.64]) of the accommodative response; and increased self-reported vision problems (Hedge’s g = 0.63 [CI: 0.44, 0.82]) in people with ADHD compared to those without ADHD (with no significant heterogeneity). We also found meta-analytic evidence of no differences between people with and without ADHD on retinal nerve fiber layer thickness (Hedge’s g = −0.19 [CI: −0.41, 0.02]) and refractive error (Hedge’s g = 0.08 [CI: −0.26, 0.42]) (with no significant heterogeneity). Discussion: ADHD is associated with some self-reported and objectively ascertained functional vision problems, but not with structural alterations of the eye. Further studies should clarify the causal relationship, if any, between ADHD and problems of vision. Trial registration: PROSPERO registration: CRD42021256352.

Theories of differences in resting-state arousal in autistic individuals are influential. Differences in arousal during resting-state would impact engagement and adaptation to the environment, having a cascading effect on development of attentional and social skills. We systematically evaluated the evidence for differences in measures of autonomic arousal (heart rate, pupillometry or electrodermal activity) during resting-state in autistic individuals; to understand whether certain contextual or methodological factors impact reports of such differences. We searched PsycInfo, MEDLINE and EMBASE databases for papers published until 16th May 2019. Of 1207 titles initially identified, 60 met inclusion criteria. Of the 51 studies that investigated group differences between neurotypical and autistic participants, 60.8 % found evidence of group differences. While findings of hyperarousal were more common, particularly using indices of parasympathetic function, findings of hypo-arousal and autonomic dysregulation were also consistently present. Importantly, experimental context played a role in revealing such differences. The evidence is discussed with regard to important methodological factors and implications for future research are described.

We conducted a systematic review and meta-analysis to quantify the effect of ADHD medication on QoL, and to understand if this effect differs between stimulants and non-stimulants. From the dataset of a published network meta-analysis (Cortese et al., 2018¹), updated on 27^th February 2023 (https://med-adhd.org/), we identified randomized controlled trials (RCTs) of ADHD medications for individuals aged 6 or more with a diagnosis of ADHD based on DSM (from III to 5 editions) or ICD (9 or 10), reporting data on QoL (measured with a validated scale). The risk of bias for each RCTs was assessed using the Cochrane Risk of Bias tool 2. Multi-level meta-analytic models were conducted with R 4.3.1. We included 17 RCTs (5,388 participants in total; 56% randomized to active medication) in the meta-analyses. We found that amphetamines (Hedge's g = 0.51, 95% CI = 0.08, 0.94), methylphenidate (0.38; 0.23, 0.54), and atomoxetine (0.30; 0.19, 0.40) were significantly more efficacious than placebo in improving QoL in people with ADHD, with moderate effect size. For atomoxetine, these effects were not moderated by the length of intervention, nor differed between children/adolescents and adults. In addition to being efficacious in reducing ADHD core symptoms' severity, both stimulant and non-stimulant medications are efficacious in improving QoL in people with ADHD, albeit with lower effect sizes. Future research should explore whether and to what degree combining pharmacological and non-pharmacological interventions is likely to further improve QoL in people with ADHD. Effects of pharmacological treatment for ADHD on quality of life: a systematic review and meta-analysis; https://osf.io/; qvgps.

According to the arousal-mood hypothesis, changes in arousal and mood when exposed to auditory stimulation underlie the detrimental effects or improvements in cognitive performance. Findings supporting or against this hypothesis are, however, often based on subjective ratings of arousal rather than autonomic/physiological indices of arousal. To assess the arousal-mood hypothesis, we carried out a systematic review of the literature on 31 studies investigating cardiac, electrodermal, and pupillometry measures when exposed to different types of auditory stimulation (music, ambient noise, white noise, and binaural beats) in relation to cognitive performance. Our review suggests that the effects of music, noise, or binaural beats on cardiac, electrodermal, and pupillometry measures in relation to cognitive performance are either mixed or insufficient to draw conclusions. Importantly, the evidence for or against the arousal-mood hypothesis is at best indirect because autonomic arousal and cognitive performance are often considered separately. Future research is needed to directly evaluate the effects of auditory stimulation on autonomic arousal and cognitive performance holistically.