Autism spectrum disorder (ASD) is a neurodevelopmental disorder often associated with changes in cortical volume. The constituents of cortical volume – cortical thickness and surface area – have separable developmental trajectories and are related to different neurobiological processes. However, little is known about the developmental trajectories of cortical thickness and surface area in ASD. In this magnetic resonance imaging (MRI) study, we used an accelerated longitudinal design to investigate the cortical development in 90 individuals with ASD and 90 typically developing controls, aged 9 to 20 years. We quantified cortical measures using the FreeSurfer software package, and then used linear mixed model analyses to estimate the developmental trajectories for each cortical measure. Our primary finding was that the development of surface area follows a linear trajectory in ASD that differs from typically developing controls. In typical development, we found a decline in cortical surface area between the ages of 9 and 20 that was absent in ASD. We found this pattern in all regions where developmental trajectories for surface area differed between groups. When we applied a more stringent correction that takes the interdependency of measures into account, this effect on cortical surface area retained significance for left banks of superior temporal sulcus, postcentral area, and right supramarginal area. These areas have previously been implicated in ASD and are involved in the interpretation and processing of audiovisual social stimuli and distinction between self and others. Although some differences in cortical volume and thickness were found, none survived the more stringent correction for multiple testing. This study underscores the importance of distinguishing between cortical surface area and thickness in investigating cortical development, and suggests the development of cortical surface area is of importance to ASD.

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Background Synthetic cannabinoids (SCs) are a class of new psychoactive substances that have been rapidly evolving around the world throughout recent years. Many different synthetic cannabinoid analogues are on the consumer market and sold under misleading names, like “spice” or “incense.” A limited number of studies have reported serious health effects associated with SC use. In this study, we compared clinical and subclinical psychopathological symptoms associated with SC use and natural cannabis (NC) use. Methods A convenience sample of 367 NC and SC users was recruited online, including four validated psychometric questionnaires: The Drug Use Disorders Identification Test (DUDIT), Insomnia Severity Index (ISI), Altman Mania Scale (Altman), and Brief Symptom Inventory (BSI). The two groups were compared with analysis of variance (ANOVA) and covariance (ANCOVA), chi 2 tests, and logistic regression when appropriate. Results The SC user group did not differ in age from the NC user group (27.7 years), but contained less females (21% and 30%, respectively). SC users scored higher than NC users on all used psychometric measures, indicating a higher likelihood of drug abuse, sleep problems, (hypo)manic symptoms, and the nine dimensions comprising the BSI, somatization, obsessive-compulsive behavior, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism. Odds ratios (95% CI) for the SC user group vs NC user group were, respectively, drug dependence 3.56 (1.77–7.16), (severe) insomnia 5.01 (2.10–11.92), (hypo-)mania 5.18 (2.04–13.14), and BSI psychopathology 5.21 (2.96–9.17). Discussion This study shows that SC use is associated with increased mental health symptomatology compared to NC use.

Autism spectrum disorders (ASD) are neurodevelopmental disorders that are marked by deficits in social interactions, communication, and stereotyped and repetitive behaviour. The third cluster of symptoms is often severely impairing, and the fixed routines, rituals and repetitive activities cause much suffering for affected individuals. Furthermore, they often cause severe loss of functioning and these behaviours are one of the main reasons for pharmacological interventions in children with ASD. Managing interactions with individuals who experience these symptoms is often challenging for clinicians and for caregivers. The neurobiology underlying these symptoms is not well understood. There is some evidence that repetitive behaviour is related to changes in fronto-striatal circuits, 1 and this relationship appears quite marked in ASD.2,3 Recently, we reported that a specific type of repetitive behaviour 'insistence on sameness' , a factor derived from the Autism Diagnostic Interview (ADI), 4 is associated with polymorphisms of single-nucleotide polymorphism (SNP) rs167771 of the dopamine-3-receptor gene (DRD3) in ASD.5 This is of interest for several reasons. First, polymorphisms of rs167771 have now been associated with ASD in British, Dutch and Spanish samples. 6,7 Second, DRD3 is relatively overexpressed in the striatum, including the caudate, which in turn is affected in ASD.8 Third, the rs167771 SNP was recently related to extrapyramidal symptoms (EPS) induced by risperidone.9 Risperidone is frequently administered for the treatment of stereotyped behaviour in ASD. In sum, from these studies there seems to be a relationship between rs167771, striatum and repetitive and stereotyped symptoms in ASD. To make neurobiological findings relevant for daily clinical practice it is pivotal to understand the relationship between genetic risk factors, on the one hand, and brain changes and symptoms on the other. Given the suggestive but inconclusive evidence of a relationship between polymorphisms of DRD3, striatum and stereotyped and repetitive behaviour, we set out to investigate whether polymorphisms of the rs167771 SNP were related to striatal volume and stereotyped behaviour in ASD. MethodThe volumes of striatum (caudate, putamen) and the whole brain were measured on anatomical magnetic resonance imaging (MRI) scans from 86 participants with ASD. Prior to inclusion, written informed consent was obtained from the participants and their parents and the study was approved by the ethics committee of the UMC Utrecht, The Netherlands. All participants met the DSM-IV(TR) criteria for ASD.9 Clinical assessment was based on multidisciplinary evaluation and included the Autism Diagnostic Interview-Revised (ADI-R) 10 and the Autism Diagnostic Observation Schedule (ADOS).11 MRI scans were acquired on a 1.5-T scanner (Philips, Best, The Netherlands). T 1 -weighted three-dimensional (3-D) fast-field echo scans with 1.2 mm and T 2 -weighted dual echo turbo spin echo scans with 1.6 mm contiguous coronal slices of the whole head wer...