Probing the overarching continuum theory: data-driven phenotypic clustering of children with ASD or ADHD.

The clinical validity of the distinction between ADHD and ASD is a longstanding discussion. Recent advances in the realm of data-driven analytic techniques now enable us to formally investigate theories aiming to explain the frequent co-occurrence of these neurodevelopmental conditions. In this study, we probe different theoretical positions by means of a pre-registered integrative approach of novel classification, subgrouping, and taxometric techniques in a representative sample (N = 434), and replicate the results in an independent sample (N = 219) of children (ADHD, ASD, and typically developing) aged 7-14 years. First, Random Forest Classification could predict diagnostic groups based on questionnaire data with limited accuracy-suggesting some remaining overlap in behavioral symptoms between them. Second, community detection identified four distinct groups, but none of them showed a symptom profile clearly related to either ADHD or ASD in neither the original sample nor the replication sample. Third, taxometric analyses showed evidence for a categorical distinction between ASD and typically developing children, a dimensional characterization of the difference between ADHD and typically developing children, and mixed results for the distinction between the diagnostic groups. We present a novel framework of cutting-edge statistical techniques which represent recent advances in both the models and the data used for research in psychiatric nosology. Our results suggest that ASD and ADHD cannot be unambiguously characterized as either two separate clinical entities or opposite ends of a spectrum, and highlight the need to study ADHD and ASD traits in tandem.

[Adolescents with concurrent ADHD and substance use disorder; international consensus]. / Jongeren met een stoornis in het gebruik van middelen en ADHD: internationale consensus.

BACKGROUND: Substance use disorder (SUD) is common among youths with attention-deficit/hyperactivity disorder (ADHD). Co-morbid ADHD and SUD in youths complicates screening, diagnosis, and treatment of both disorders and is associated with worse treatment prognosis. Limited research in youths with SUD and co-morbid ADHD provides insufficient basis for firm recommendations. To offer clinicians some guidance on this topic, we present the results of an international consensus procedure. AIM: To summarize an international consensus on diagnosis and treatment of young people with comorbid ADHD and SUD. METHOD: In a modified Delphi-study, a multidisciplinary, international group of 55 experts strived to reach consensus on 37 recommendations. RESULTS: Consensus was reached on 36 recommendations. Routine screening of ADHD and/or SUD is important. For the treatment of co-morbid SUD and ADHD in youths, both psychosocial and pharmacological treatment should be considered. Psychosocial treatment should preferably consist of psychoeducation, motivational interviewing (MI), and cognitive behavioral therapy (CBT) focused on SUD or both disorders. Long-acting stimulants are recommended as first choice pharmacotherapy, preferably embedded in psychosocial treatment. Experts did not agree on the precondition that patients need to be abstinent before starting stimulant treatment. CONCLUSION: Clinicians and youths with co-morbid SUD and ADHD can use this international consensus to choose the best possible treatment.

Non-pharmacological interventions for challenging behaviours of adults with intellectual disabilities: A meta-analysis.

BACKGROUND: Non-pharmacological interventions are recommended for the treatment of challenging behaviours in individuals with intellectual disabilities by clinical guidelines. However, evidence for their effectiveness is ambiguous. The aim of the current meta-analysis is to update the existing evidence, to investigate long-term outcome, and to examine whether intervention type, delivery mode, and study design were associated with differences in effectiveness. METHOD: An electronic search was conducted using the databases Medline, Eric, PsychINFO and Cinahl. Studies with experimental or quasi-experimental designs were included. We performed an overall random-effect meta-analysis and subgroup analyses. RESULTS: We found a significant moderate overall effect of non-pharmacological interventions on challenging behaviours (d = 0.573, 95% CI [0.352-0.795]), and this effect appears to be longlasting. Interventions combining mindfulness and behavioural techniques showed to be more effective than other interventions. However, this result should be interpreted with care due to possible overestimation of the subgroup analysis. No differences in effectiveness were found across assessment times, delivery modes or study designs. CONCLUSIONS: Non-pharmacological interventions appear to be moderately effective on the short and long term in reducing challenging behaviours in adults with intellectual disabilities.

Is camouflaging unique for autism? A comparison of camouflaging between adults with autism and ADHD.

Camouflaging (using (un)conscious strategies to appear as non-autistic) is thought to be an important reason for late autism diagnoses and mental health difficulties. However, it is unclear whether only autistic people camouflage or whether people with other neurodevelopmental or mental health conditions also use similar camouflaging strategies. Therefore, in this preregistered study (AsPredicted: #41811) study, we investigated if adults with attention-deficit/hyperactivity-disorder (ADHD) also camouflage. Adults aged 30-90 years filled in the Dutch Camouflaging Autistic Traits Questionnaire (CAT-Q-NL), the ADHD Self-Report (ADHD-SR) and the Autism Spectrum Quotient (AQ). We investigated differences in camouflaging between adults with ADHD, autism, and a comparison group in an age and sex-matched subsample (N = 105 per group). We explored if autism and ADHD traits explained camouflaging levels in adults with an autism and/or ADHD diagnosis (N = 477). Adults with ADHD scored higher on total camouflaging and assimilation subscale compared to the comparison group. However, adults with ADHD scored lower on total camouflaging, and subscales compensation and assimilation than autistic adults. Autism traits, but not ADHD traits, were a significant predictor of camouflaging, independent of diagnosis. Thus, camouflaging does not seem to be unique to autistic adults, since adults with ADHD also show camouflaging behavior, even though not as much as autistic adults. However, as the CAT-Q-NL specifically measures camouflaging of autistic traits it is important to develop more general measures of camouflaging, to compare camouflaging more reliably in people with different mental health conditions. Furthermore, focusing on camouflaging in adults with ADHD, including potential consequences for late diagnoses and mental health seems a promising future research avenue.

Memory strategies in autistic and older adults.

Memory strategies in autistic adults seem to mimic strategies at older age, as both younger autistic and older non-autistic individuals use fewer semantic features in visual memory tasks. Therefore, the current study aims to investigate whether early differences in memory strategies lead to altered age-related effects in autism, particularly whether initial difficulties in strategy use become advantageous at older age (i.e., "protective aging"). A total of 147 participants across four groups (autistic younger/older, non-autistic younger/older) completed an online assessment. This assessment included a recognition version of the Visual Patterns Test (VPT) to evaluate semantic strategy use in visual memory, the Just Noticeable Difference (JND) size task for assessing visual processing, and the Multifactorial Memory Questionnaire to evaluate subjective memory functioning and strategy use (MMQ). Unexpectedly, all groups benefited from semantic features on the VPT, although the older groups performed less accurately and slower than the younger groups. The JND Size task showed no group differences. Autistic adults rated their MMQ memory as worse than non-autistic adults, despite reporting greater strategy use. These results indicate that cognitive strategies might be more similar between younger/older and autistic/non-autistic people than previously expected, although notable discrepancies between objective and subjective measures were present. They also substantiate previously reported parallel (i.e., similar) age-related effects between autistic and non-autistic people.

A longitudinal study on cognitive aging in autism.

Longitudinal studies on cognitive aging in autism are scarce, and largely underpowered, yet essential to obtain more conclusive results on cognitive changes in autism during adulthood. In the largest longitudinal study on cognition thus far, we aimed to get more insight into cognitive aging in autism. As pre-registered, we computed reliable change indices (RCIs) and multilevel models to estimate cognitive changes in 128 autistic, and 112 non-autistic adults (range: 24-85 yrs.) over two to three timepoints (average interval: 3.5 yrs.). Participants were tested on 15 outcome measures, covering verbal memory, visual (working) memory, prospective memory, theory of mind, fluency, response speed, inhibition, planning, and switching. RCIs showed no significant differences between groups (autism/no-autism) in changes over time. Using multilevel models, most tasks showed sensitivity to cross-sectional age-related effects, and/or longitudinal changes, with worse performance at older age, and later timepoints. However, effects were not significantly different between the autism and no-autism group. This lack of group differences was substantiated by additional Bayesian analyses. In sum, the current study provides evidence for parallel (similar) cognitive aging in autism. Specifically, autistic individuals diagnosed in adulthood, without intellectual disability, do not seem at risk for accelerated cognitive decline.

Role of conduct problems in the relation between Attention-Deficit Hyperactivity disorder, substance use, and gaming.

Known comorbidities for Attention-Deficit Hyperactivity Disorder (ADHD) include conduct problems, substance use disorder and gaming. Comorbidity with conduct problems may increase the risk for substance use disorder and gaming in individuals with ADHD. The aim of the study was to build a causal model of the relationships between ADHD and comorbid conduct problems, and alcohol, nicotine, and other substance use, and gaming habits, while accounting for age and sex. We used a state-of-the-art causal discovery algorithm to analyze a case-only sample of 362 ADHD-diagnosed individuals in the ages 12-24 years. We found that conduct problem severity mediates between ADHD severity and nicotine use, but not with more severe alcohol or substance use. More severe ADHD-inattentive symptoms lead to more severe gaming habits. Furthermore, our model suggests that ADHD severity has no influence on severity of alcohol or other drug use. Our findings suggest that ADHD severity is a risk factor for nicotine use, and that this effect is fully mediated by conduct problem severity. Finally, ADHD-inattentive severity was a risk factor for gaming, suggesting that gaming dependence has a different causal pathway than substance dependence and should be treated differently. By identifying these intervention points, our model can aid both researchers and clinicians.