DRD3 gene and striatum in autism spectrum disorder.

A single-nucleotide polymorphism (SNP) of the DRD3 gene (rs167771) was recently associated with autism spectrum disorders (ASD). Different polymorphisms of rs167771 corresponded to varying degrees of stereotyped behaviour. As DRD3 receptors are relatively overexpressed in the striatum, we investigated whether striatal volume was related to these polymorphisms in autism. We assessed volumes of caudate nucleus and putamen in 86 participants with ASD (mean age 15.3 years). MANCOVA showed an association between alleles of the rs167771 SNP and the volume of striatal structures. Furthermore, greater caudate nucleus volume correlated with stereotyped behaviour. These findings support a relationship between DRD3 gene SNPs, striatum and stereotyped behaviour in ASD.

Psychopathological symptoms associated with synthetic cannabinoid use: a comparison with natural cannabis.

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), chi2 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.

No evidence of differences in cognitive control in children with autism spectrum disorder or obsessive-compulsive disorder: An fMRI study.

Repetitive behaviors are among the core symptoms of both Autism Spectrum Disorder (ASD) and Obsessive-Compulsive Disorder (OCD) and are thought to be associated with impairments in cognitive control. However, it is still unknown how deficits in cognitive control and associated neural circuitry relate to the quality or severity of repetitive behavior in children with these disorders. Therefore, we investigated the behavioral and neural correlates of cognitive control using a modified stop-signal task in a multicenter study of children (aged 8-12 years) with ASD, OCD and typically developing (TD) children (N = 95). As both ASD and OCD have high levels of comorbidity with Attention Deficit/Hyperactivity Disorder (ADHD), we did an exploratory analysis addressing ADHD-symptoms. We found that children with ASD and OCD did not show deficits in cognitive control or changes in brain activity in task-relevant neural networks when compared to TD children. However, increased activity in prefrontal brain areas was associated with increased symptoms of comorbid ADHD. As such, this study does not support differences in cognitive control or associated neural circuitry in children with ASD and OCD, but rather suggests that changes in cognitive control in these disorders may be related to symptoms of comorbid ADHD.

Development of cortical thickness and surface area in autism spectrum disorder.

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.