Introduction: Autism spectrum disorder (ASD) is one of the most prevalent neurodevelopmental disorders and has a major genetic heterogeneity. Comparing monogenetic causes of ASD can contribute to...Show moreIntroduction: Autism spectrum disorder (ASD) is one of the most prevalent neurodevelopmental disorders and has a major genetic heterogeneity. Comparing monogenetic causes of ASD can contribute to understanding its genetic aetiology. This study compares patients with fragile X syndrome (FXS) to patients with tuberous sclerosis complex (TSC) in terms of ASD severity and symptomatology to create an image of their ASD symptom profiles. This could lead to more focused diagnoses and specialized treatment for these patient groups. Methods: This study included children and adolescents (ages 1–18, mean age = 9.01 years) with FXS (n = 57, 80.7% males) or TSC (n = 105, 49.5% males). The second editions of the Autism Diagnostic Observation Scale and the Social Responsiveness Scale were used to assess ASD symptomatology. First, the prevalence of official ASD diagnoses among FXS and TSC patients was compared. Next, patients with an official diagnosis were compared in terms of (1) overall autism severity, (2) severity of problems within the restricted and repetitive behaviour (RRB) and social affect domains, and (3) more specific ASD symptoms such as ‘reciprocal communication’. Intelligence quotient (IQ; mean IQ = 58.08) was included as a predictor in the logistic regression and as a covariate in both between-group analyses of covariance and all multivariate analyses of covariance. Results: FXS patients are more likely to receive an official ASD diagnosis (χ2 = 4.081, p = .043). Higher IQ is related to less autism symptomatology (χ2 = 8.592, p = .003). Overall, ASD severity of patients with an official ASD diagnosis does not differ between the patient groups. The FXS patients with ASD exhibited more severe RRB (F = 8.21, p = .005). No significant difference was found for social affect or any specific symptoms. Conclusion: ASD prevalence is higher in children with FXS than in children with TSC, with FXS patients exhibiting more severe RRB. This study illustrates the relevance of comparing symptomatology in monogenetic causes of ASD, indicating that syndrome-symptom relationships can be found. This could lead to earlier intervention and focused treatment for these patients and contributes to research on the genetic aetiology of ASD.Show less
Background and aims: Psychotic disorders (PD) are often accompanied by substance (ab)use. Recent studies demonstrated a connection between these conditions through a common neurocognitive...Show moreBackground and aims: Psychotic disorders (PD) are often accompanied by substance (ab)use. Recent studies demonstrated a connection between these conditions through a common neurocognitive dysfunction. This common dysfunction concerns the executive functions (EF). Through this way it affects both cognitive control and mechanisms of motivation/reward. An EF dysfunction is a core feature of both PD and substance (ab)use. Moreover, it is found to be present prior to the onset of both conditions. It is suggested that this common EF dysfunction highlights a vulnerability for comorbidity. Hence, this study investigated whether a common neurocognitive dysfunction is associated to the co-morbidity of substance (ab)use and PD. Investigating EF in co-morbidity is especially relevant for theories of aetiology, prevention and treatment. First, we examined whether poor EF predicts an increase in substance use in PD patients. Second, we examined whether poor EF, combined with substance use, predicts an increase in substance dependency. Methods: This crosssectional study included 90 patients diagnosed with PD (18-65 years). Data were obtained through self-report questionnaires that measured EF, substance use and -dependency. Three multiple linear regression analyses were calculated to evaluate whether EF scores predicted substance use; three moderated binary logistic regression analyses were calculated to evaluate whether EF scores, moderated by substance use, predicted substance dependency. Findings: Results showed that Initiative deficits predicted substance use (p=.01). Deficits of Emotional regulation (p=.04) and Working memory (p=.03), moderated by substance use, predicted a decrease of dependency. Conclusions: Our results partially confirmed that poor EF predicted substance use and -dependency in PD. It did not lend sufficient support for the idea that the co-morbidity of substance (ab)use and PD is associated with a common EF dysfunction. Nevertheless, results demonstrated a relation between EF and substance (ab)use, namely that PD patients use substances as a means of self-medication in order to cope with an EF dysfunction. It can be concluded that this self-medicative behaviour promotes the development of co-morbid substance (ab)use in PD. This study offers new insights into the selfmedication hypothesis. It demonstrated that, besides psychotic symptoms, an EF dysfunction induces self-medicative substance use in PD. Clinical implications may concern prevention techniques and treatment methods.Show less
