Faculty Bibliography

BACKGROUND: Diffusion tensor imaging studies have shown atypical fractional anisotropy (FA) in individuals with attention-deficit/hyperactivity disorder (ADHD), albeit with conflicting results. We performed meta-analyses of whole-brain voxel-based analyses (WBVBA) and tract-based spatial statistics (TBSS) studies in ADHD, along with a qualitative review of TBSS studies addressing the issue of head motion, which may bias results. METHODS: We conducted a systematic literature search (last search on April 1st, 2016) to identify studies comparing FA values between individuals with ADHD and typically developing (TD) participants. Signed differential mapping was used to compute effect sizes and integrate WBVBA and TBSS studies, respectively. TBSS datasets reporting no between-group motion differences were identified. RESULTS: We identified 14 WBVBA (ADHDn = 314, TDn = 278) and 13 TBSS datasets (ADHDn = 557, TDn = 568). WBVBA meta-analysis showed both significantly lower and higher FA values in individuals with ADHD; TBSS meta-analysis showed significantly lower FA in ADHD compared with TD in four clusters: two in the corpus callosum (isthmus and posterior midbody), one in right inferior fronto-occipital fasciculus, and one in left inferior longitudinal fasciculus. However, four of six datasets confirming no group-differences in motion showed no significant between-group FA differences. CONCLUSIONS: A growing diffusion tensor imaging (DTI) literature (total N = 1,717) and a plethora of apparent findings suggest atypical interhemispheric connection in ADHD. However, FA results in ADHD should be considered with caution, since many studies did not examine potential group differences in head motion, and most of the studies reporting no difference in motion showed no significant results. Future studies should address head motion as a priority and assure that groups do not differ in head motion.

A systematic review with meta-analyses was performed to: 1) quantify the association between ADHD and risk of unintentional physical injuries in children/adolescents ("risk analysis"); 2) assess the effect of ADHD medications on this risk ("medication analysis"). We searched 114 databases through June 2017. For the risk analysis, studies reporting sex-controlled odds ratios (ORs) or hazard ratios (HRs) estimating the association between ADHD and injuries were combined. Pooled ORs (28 studies, 4,055,620 individuals without and 350,938 with ADHD) and HRs (4 studies, 901,891 individuals without and 20,363 with ADHD) were 1.53 (95% CI=1.40,1.67) and 1.39 (95% CI=1.06,1.83), respectively. For the medication analysis, we meta-analysed studies that avoided the confounding-by-indication bias [four studies with a self-controlled methodology and another comparing risk over time and groups (a "difference in differences" methodology)]. The pooled effect size was 0.879 (95% CI=0.838,0.922) (13,254 individuals with ADHD). ADHD is significantly associated with an increased risk of unintentional injuries and ADHD medications have a protective effect, at least in the short term, as indicated by self-controlled studies.

Emotional dysregulation (ED) is a dysfunction in modifying an emotional state in an adaptive and goal oriented way, with excitability, ease anger, and mood lability. It is present in up to 70% of adults with ADHD, regardless of other comorbidities, and substantially worsens the psychosocial outcomes of the disorder. Besides fronto-parietal circuits mediating top-down control, brain regions involved in bottom-up processes (e.g., amygdala, orbitofrontal cortex, and ventral striatum) are implicated in ED. We performed a systematic review/meta-analysis of double-blind randomized controlled trials of ADHD medications to assess their effects on ED in adults with ADHD. We searched an extensive set of databases, international trials registries, and contacted study authors/drug companies for unpublished data. We retained 21 trials. We found small-to-moderate effects (methylphenidate: SMD=0.34, 95% CI=0.23-0.45; atomoxetine: SMD=0.24, 95% CI=0.15-0.34; lisdexamfetamine: SMD=0.50, 95% CI=0.21-0.8). We suggest that, whilst ADHD medications are effective on ADHD core symptoms, they may be less effective on bottom-up mechanisms underlying ED. Further research on novel pharmacological and non-pharmacological strategies for ED in adults with ADHD is warranted.

INTRODUCTION: Attention-deficit hyperactivity disorder (ADHD) has been related to increased rates of unintentional injuries. However, the magnitude of the effect and to which extent variables such as sex, age or comorbidity can influence this relationship is unknown. Additionally, and importantly, it is unclear if, and to which degree, ADHD medications can decrease the number of unintentional injuries. Due to the amount of economic and social resources invested in the treatment of injuries, filling these gaps in the literature is highly relevant from a public health standpoint. Here, we present a protocol for a systematic review and meta-analysis to estimate the relationship between ADHD and unintentional injuries and assess the impact of pharmacological treatment for ADHD METHODS AND ANALYSIS: We will combine results from 114 bibliographic databases for studies relating ADHD and risk of injuries. Bibliographic searches and data extraction will be carried out independently by two researchers. The studies' risk of bias will be assessed using the Newcastle-Ottawa Scale. Articles reporting ORs or HRs of suffering an injury in ADHD compared with controls (or enough data to calculate them) will be combined using Robust Variance Estimation, a method that permits to include multiple non-independent outcomes in the analysis. All analyses will be carried out in Stata. Age, sex and comorbid conduct disorders will be considered as potential causes of variance and their effect analysed through meta-regression and subgroup analysis. Sensitivity analyses will exclude articles with longer follow-ups, non-stringent definitions of ADHD or controls and statistically uncontrolled/controlled outcomes. Studies implementing a self-controlled case series methodology to investigate if ADHD drugs reduce the risk of injuries will be combined with a generalised linear mixed model using the Poisson distribution and a log link function. REGISTRATION DETAILS: PROSPERO-Prospective Register of Systematic Reviews (CRD42017064967).

Restless legs syndrome (RLS) is a relatively common neurological disorder in childhood, although it is usually overlooked due to the atypical presentation in children and associated comorbid conditions that may affect its clinical presentation. Here, we aimed to perform, for the first time, a systematic review of studies reporting the association between RLS in children and adolescents (<18 y) and somatic or neuropsychiatric conditions. We searched for peer-reviewed studies in PubMed, Ovid (including PsycINFO, Ovid MEDLINE(R), and Embase), Web of Knowledge (Web of Science, Biological abstracts, BIOSIS, FSTA) through November 2015, with no language restrictions. We found 42 pertinent studies. Based on the retrieved studies, we discuss the association between RLS and a number of conditions, including growing pains, kidney disease, migraine, diabetes, epilepsy, rheumatologic disorders, cardiovascular disease, liver and gastrointestinal disorders, and neuropsychiatric disorders (e.g., attention deficit hyperactivity disorder (ADHD), depression, and conduct disorder). Our systematic review provides empirical evidence supporting the notion that RLS in children is comorbid with a number of somatic and neuropsychiatric conditions. We posit that the awareness on comorbid diseases/disorders is pivotal to improve the diagnosis and management of RLS and might suggest fruitful avenues to elucidate the pathophysiology of RLS in children.

BACKGROUND: Despite meta-analytic evidence for the association between attention-deficit/hyperactivity disorder (ADHD) and overweight/obesity, the mechanisms underlying the association are yet to be fully understood. METHODS: By linking multiple Swedish national and regional registers, we identified 472,735 index males born during 1973-1992, with information on body weight and height directly measured before they were conscripted for military service. We further identified 523,237 full siblings born during 1973-2002 for the index males. All individuals were followed up from their third birthday to December 31, 2009 for ADHD diagnosis. Logistic regression models were used to estimate the association between overweight/obesity in index males and ADHD in their full siblings. RESULTS: Siblings of index males with overweight/obesity had increased risk for ADHD (overweight: OR = 1.14, 95% CI = 1.05-1.24; obesity: OR = 1.42, 95% CI = 1.24-1.63), compared with siblings of index males with normal weight. The results were adjusted for birth year of the index male and sex of the sibling. After further adjustment for ADHD status of the index male, the familial coaggregation remained significant (overweight: OR = 1.13, 95% CI = 1.04-1.22; obesity: OR = 1.38, 95% CI = 1.21-1.57). The results were similar across sex of the siblings. CONCLUSIONS: Attention-deficit/hyperactivity disorder and overweight/obesity share familial risk factors, which are not limited to those causing overweight/obesity through the mediation of ADHD. Future research aiming at identifying family-wide environmental risk factors as well as common pleiotropic genetic variants contributing to both traits is warranted.