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This study explored whether high autistic traits, high attention deficit hyperactivity disorder (ADHD) traits and their interaction were associated with quality of life (QoL) in a sample of 556 of young-adult twins (Mean age 22 years 5 months, 52% Female). Four participant groups were created: high autistic traits, high ADHD traits, high autistic/ADHD traits, and low ADHD/autistic traits. High autistic traits were associated with lower QoL across domains (physical, psychological, social, and environmental). High ADHD traits associated with lower physical, psychological, and environmental QoL. The interaction of autistic and ADHD traits was not significant in any domain. While mental health difficulties were associated with lower QoL, after accounting for mental health, most relationships between autistic traits, ADHD traits and QoL remained.

Altered power of resting-state neurophysiological activity has been associated with autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), which commonly co-occur. We compared resting-state neurophysiological power in children with ASD, ADHD, co-occurring ASD + ADHD, and typically developing controls. Children with ASD (ASD/ASD + ADHD) showed reduced theta and alpha power compared to children without ASD (controls/ADHD). Children with ADHD (ADHD/ASD + ADHD) displayed decreased delta power compared to children without ADHD (ASD/controls). Children with ASD + ADHD largely presented as an additive co-occurrence with deficits of both disorders, although reduced theta compared to ADHD-only and reduced delta compared to controls suggested some unique markers. Identifying specific neurophysiological profiles in ASD and ADHD may assist in characterising more homogeneous subgroups to inform treatment approaches and aetiological investigations.

Aim: To characterize early changes in developmental ability, language, and adaptive behaviour in infants diagnosed with tuberous sclerosis complex (TSC), and determine whether clinical features of epilepsy influence this pathway. Method: Prospective, longitudinal data were collected within the Early Development in Tuberous Sclerosis (EDiTS) Study to track development of infants with TSC (n = 32) and typically developing infants (n = 33) between 3 and 24 months of age. Questionnaire and observational measures were used at up to seven timepoints to assess infants' adaptive behaviour, developmental ability, language, and epilepsy. Results: A significant group by age interaction effect showed that infants with TSC had lower adaptive functioning at 18 to 24 months old (intercept = 88.12, slope estimate = −0.82, p < 0.001) and lower developmental ability scores from 10 months old (intercept = 83.33, slope estimate = −1.44, p < 0.001) compared to typically developing infants. Early epilepsy severity was a significant predictor of these emerging developmental (R2 = 0.35, p = 0.004, 95% confidence interval [CI] –0.08 to −0.01) and adaptive behaviour delays (R2 = 0.34, p = 0.004, 95% CI –0.05 to −0.01]). Lower vocabulary production (intercept = −1.25, slope = −0.12, p < 0.001) and comprehension scores (intercept = 2.39, slope estimate = −0.05, p < 0.001) in infants with TSC at 24 months old were not associated with epilepsy severity. Interpretation: Divergence of developmental ability and adaptive functioning skills occur in infants with TSC from 10 and 18 months, respectively. Associations between early epilepsy severity and impaired development supports the importance of early intervention to reduce seizure severity. This original article is commented on by Jóźwiak on pages 556–557 of this issue. [ABSTRACT FROM AUTHOR]

Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) often co-occur. Children with ASD and ADHD demonstrate deficits in adaptive functioning, yet pure and comorbid groups have not been directly compared. Vineland Adaptive Behaviour Scales (VABS-II) data were examined in boys with ASD (n = 17), ADHD (n = 31) and ASD + ADHD (n = 38). Results demonstrated lower socialisation and composite scores and greater discrepancy between cognitive and adaptive abilities in the ASD + ADHD group compared to the ADHD-only group. Significant associations were shown between reduced adaptive functioning and autism symptoms, but not ADHD symptoms. Children with ASD + ADHD present with exacerbated impairments in adaptive functioning relative to children with ADHD, associated with ASD symptoms. Disentangling variation in adaptive skills may aid the assessment of complex cases.

Background: Attention deficit hyperactivity disorder (ADHD) is a common and highly heritable neurodevelopmental disorder with a complex aetiology. The identification of candidate intermediate phenotypes that are both heritable and genetically linked to ADHD may facilitate the detection of susceptibility genes and elucidate aetiological pathways. Very low-frequency (VLF; less than 0.5 Hz) electroencephalographic (EEG) activity represents a promising indicator of risk for ADHD, but it currently remains unclear as to whether it is heritable or genetically linked to the disorder. Methods: Direct-current (DC)-EEG was recorded during a cognitive activation condition in 30 monozygotic and dizygotic adolescent twin pairs concordant or discordant for high ADHD symptom scores, and 37 monozygotic and dizygotic matched-control twin pairs with low ADHD symptom scores. Structural equation modelling was used to quantify the genetic and environmental contributions to the phenotypic covariance between ADHD and VLF activity. Results: Attention deficit hyperactivity disorder was significantly associated with reduced VLF power during cognitive activation, which suggests reduced synchronization of widespread neuronal activity. Very low-frequency power demonstrated modest heritability (0.31), and the genetic correlation (-0.80) indicated a substantial degree of overlap in genetic influences on ADHD and VLF activity. Conclusions: Altered VLF activity is a potential candidate intermediate phenotype of ADHD, which warrants further investigation of underlying neurobiological and genetic mechanisms.

Aim: To examine the association between perinatal adversities and neurodevelopmental outcome in tuberous sclerosis complex (TSC). Method: The Tuberous Sclerosis 2000 study is a prospective, longitudinal UK study of TSC. In phase 1, mutation type, TSC family history, tuber characteristics, presence of cardiac rhabdomyomas, seizure characteristics, and intellectual ability were assessed in 125 children affected with TSC (64 females, 61 males; median age 39mo, range 4–254). In phase 2, 88 participants (49 females, 39 males; median age 148mo, range 93–323) were assessed for neurodevelopmental outcomes including intellectual ability, autism spectrum disorder, and attention‐deficit/hyperactivity disorder. Perinatal histories of 88 participants with TSC and 80 unaffected siblings were collected retrospectively using the Obstetric Enquiry Schedule and coded with a modified Gillberg Optimality Scale to measure levels of perinatal adversity. Data were analysed using Mann–Whitney U tests, Spearman's rank correlation, and linear regression with robust standard errors. Results: Children with familial TSC experienced significantly greater perinatal adversity than unaffected siblings. Perinatal adversity was higher in children with TSC‐affected mothers than those with unaffected mothers. There was no significant association between perinatal adversities and neurodevelopmental outcomes after controlling for confounders. Interpretation: Maternal TSC is a significant marker of elevated perinatal risk in addition to risks incurred by fetal genotype. Pregnancies complicated by maternal or fetal TSC require higher vigilance, and mechanisms underlying increased perinatal adversity require further research. What this paper adds: Higher perinatal adversity is associated with familial tuberous sclerosis complex (TSC).Maternal TSC was associated with higher frequencies of several perinatal risk markers.Paternal TSC was not associated with higher levels of perinatal adversity.Perinatal adversity levels in TSC1 and TSC2 subgroups did not differ significantly.Perinatal adversities were not associated with neurodevelopmental outcomes. What this paper adds: Higher perinatal adversity is associated with familial tuberous sclerosis complex (TSC).Maternal TSC was associated with higher frequencies of several perinatal risk markers.Paternal TSC was not associated with higher levels of perinatal adversity.Perinatal adversity levels in TSC1 and TSC2 subgroups did not differ significantly.Perinatal adversities were not associated with neurodevelopmental outcomes. This original article is commented on by Franz on pages 1184–1185 of this issue. [ABSTRACT FROM AUTHOR]

Background: Autism Spectrum Disorder (ASD) and Attention‐Deficit/Hyperactivity Disorder (ADHD) share impairments in top‐down and bottom‐up modulation of attention. However, it is not yet well understood if co‐occurrence of ASD and ADHD reflects a distinct or additive profile of attention deficits. We aimed to characterise alpha oscillatory activity (stimulus‐locked alpha desynchronisation and prestimulus alpha) as an index of integration of top‐down and bottom‐up attentional processes in ASD and ADHD. Methods: Children with ASD, ADHD, comorbid ASD+ADHD, and typically‐developing children completed a fixed‐choice reaction‐time task ('Fast task') while neurophysiological activity was recorded. Outcome measures were derived from source‐decomposed neurophysiological data. Main measures of interest were prestimulus alpha power and alpha desynchronisation (difference between poststimulus and prestimulus alpha). Poststimulus activity linked to attention allocation (P1, P3), attentional control (N2), and cognitive control (theta synchronisation, 100–600 ms) was also examined. ANOVA was used to test differences across diagnostics groups on these measures. Spearman's correlations were used to investigate the relationship between attentional control processes (alpha oscillations), central executive functions (theta synchronisation), early visual processing (P1), and behavioural performance. Results: Children with ADHD (ADHD and ASD+ADHD) showed attenuated alpha desynchronisation, indicating poor integration of top‐down and bottom‐up attentional processes. Children with ADHD showed reduced N2 and P3 amplitudes, while children with ASD (ASD and ASD+ADHD) showed greater N2 amplitude, indicating atypical attentional control and attention allocation across ASD and ADHD. In the ASD group, prestimulus alpha and theta synchronisation were negatively correlated, and alpha desynchronisation and theta synchronisation were positively correlated, suggesting an atypical association between attentional control processes and executive functions. Conclusions: ASD and ADHD are associated with disorder‐specific impairments, while children with ASD+ADHD overall presented an additive profile with attentional deficits of both disorders. Importantly, these findings may inform the improvement of transdiagnostic procedures and optimisation of personalised intervention approaches. [ABSTRACT FROM AUTHOR]

Aim: To investigate the interdependence between risk factors associated with long-term intellectual development in individuals with tuberous sclerosis complex (TSC).Method: The Tuberous Sclerosis 2000 Study is a prospective longitudinal study of individuals with TSC. In phase 1 of the study, baseline measures of intellectual ability, epilepsy, cortical tuber load, and mutation were obtained for 125 children (63 females, 62 males; median age=39mo). In phase 2, at an average of 8 years later, intellectual abilities were estimated for 88 participants with TSC and 35 unaffected siblings. Structural equation modelling was used to determine the risk pathways from genetic mutation through to IQ at phase 2.Results: Intellectual disability was present in 57% of individuals with TSC. Individuals without intellectual disability had significantly lower mean IQ compared to unaffected siblings, supporting specific genetic factors associated with intellectual impairment. Individuals with TSC who had a slower gain in IQ from infancy to middle childhood were younger at seizure onset and had increased infant seizure severity. Structural equation modelling indicated indirect pathways from genetic mutation, to tuber count, to seizure severity in infancy, through to IQ in middle childhood and adolescence.Interpretation: Early-onset and severe epilepsy in the first 2 years of life are associated with increased risk of long-term intellectual disability in individuals with TSC, emphasizing the importance of early and effective treatment or prevention of epilepsy.What This Paper Adds: Intellectual disability was present in 57% of individuals with tuberous sclerosis complex (TSC). Those with TSC without intellectual disability had significantly lower mean IQ compared to unaffected siblings. Earlier onset and greater severity of seizures in the first 2 years were observed in individuals with a slower gain in intellectual ability. Risk pathways through seizures in the first 2 years predict long-term cognitive outcomes in individuals with TSC. [ABSTRACT FROM AUTHOR]