Intergenerational transmission: Theoretical and methodological issues and an introduction to four Dutch cohorts.

Behaviors, traits and characteristics are transmitted from parents to offspring because of complex genetic and non-genetic processes. We review genetic and non-genetic mechanisms of intergenerational transmission of psychopathology and parenting and focus on recent methodological advances in disentangling genetic and non-genetic factors. In light of this review, we propose that future studies on intergenerational transmission should aim to disentangle genetic and non-genetic transmission, take a long-term longitudinal perspective, and focus on paternal and maternal intergenerational transmission.

The association of developmental trajectories of adolescent mental health with early-adult functioning.

Background: Mental health problems during adolescence may create a problematic start into adulthood for affected individuals. Usually, categorical indicators of adolescent mental health issues (yes/no psychiatric disorder) are used in studies into long-term functional outcomes. This however does not take into account the full spectrum of mental health, nor does it consider the trajectory of mental health problem development over time.

Examining the intertwined development of prosocial skills and ASD symptoms in adolescence.

Autism spectrum disorder (ASD) and reduced prosocial behaviour are strongly intertwined. However, social interactions with peers may be increasingly practiced over the course of development and may instigate a reduction in ASD symptoms and vice versa. We, therefore, sought to determine if, during adolescence, possible improvements in prosocial behaviours and ASD symptoms may benefit one another over time.

A Causal and Mediation Analysis of the Comorbidity Between Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD).

Autism spectrum disorder (ASD) and Attention-deficit/hyperactivity disorder (ADHD) are often comorbid. The purpose of this study is to explore the relationships between ASD and ADHD symptoms by applying causal modeling. We used a large phenotypic data set of 417 children with ASD and/or ADHD, 562 affected and unaffected siblings, and 414 controls, to infer a structural equation model using a causal discovery algorithm.

Identifying Unique Versus Shared Pre- and Perinatal Risk Factors for ASD and ADHD Using a Simplex-Multiplex Stratification.

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) frequently co-occur. Besides shared genetic factors, pre- and perinatal risk factors (PPFs) may determine if ASD, ADHD, or the combination of both disorders becomes manifest. This study aimed to test shared and unique involvement of PPFs for ASD and ADHD, using an approach that stratifies the sample into affected/unaffected offspring and single-incidence (SPX) versus multi-incidence (MPX) families.

Does the cognitive architecture of simplex and multiplex ASD families differ?

Children with an autism spectrum disorder (ASD) and their unaffected siblings from 54 simplex (SPX, one individual in the family affected) and 59 multiplex (MPX, two or more individuals affected) families, and 124 controls were assessed on intelligence, social cognition and executive functions. SPX and MPX ASD probands displayed similar cognitive profiles, but within-family contrasts were highest in SPX families, suggesting SPX-MPX stratification may help parse etiological heterogeneity of ASD. Unaffected siblings (regardless SPX or MPX) were mostly unimpaired, suggesting that cognitive problems may be part of the defining features of ASD, rather than being an endophenotypic trait.

How 'core' are motor timing difficulties in ADHD? A latent class comparison of pure and comorbid ADHD classes.

Unlabelled: Children with attention-deficit/hyperactivity disorder (ADHD) have motor timing difficulties. This study examined whether affected motor timing accuracy and variability are specific for ADHD, or that comorbidity with autism spectrum disorders (ASD) contributes to these motor timing difficulties. An 80-trial motor timing task measuring accuracy (μ), variability (σ) and infrequent long response times (τ) in estimating a 1-s interval was administered to 283 children and adolescents (8-17 years) from both a clinic and population based sample.

Contribution of common and rare variants of the PTCHD1 gene to autism spectrum disorders and intellectual disability.

Recent findings revealed rare copy number variants and missense changes in the X-linked gene PTCHD1 in autism spectrum disorder (ASD) and intellectual disability (ID). Here, we aim to explore the contribution of common PTCHD1 variants in ASD and gain additional evidence for the role of rare variants of this gene in ASD and ID. A two-stage case-control association study investigated 28 tag single nucleotide polymorphisms (SNPs) in 994 ASD cases and 1035 controls from four European populations.

Cognitive impairments are different in single-incidence and multi-incidence ADHD families.

Background: We may improve our understanding of the role of common versus unique risk factors in attention-deficit/hyperactivity disorder (ADHD) by examining ADHD-related cognitive deficits in single- (SPX), and multi-incidence (MPX) families. Given that individuals from multiplex (MPX) families are likely to share genetic vulnerability for the disorder, whereas simplex (SPX) ADHD may be the result of sporadic (non-)genetic causes unique to the patient, we hypothesized that cognitive impairments may be different in SPX and MPX ADHD as indicated by (a) the presence of cognitive deficits in MPX, but not SPX unaffected siblings and (b) dissimilar cognitive profiles in SPX and MPX ADHD patients.

Methods: Tasks measuring total IQ, verbal attention, executive functioning, motor functioning, and time estimation were administered to 31 SPX/264 MPX ADHD probands, 47 SPX/123 MPX unaffected siblings, and 263 controls, aged 6-19 years.

Simplex and multiplex stratification in ASD and ADHD families: a promising approach for identifying overlapping and unique underpinnings of ASD and ADHD?

Autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD) are highly heterogeneous neuropsychiatric disorders, that frequently co-occur. This study examined whether stratification into single-incidence (SPX) and multi-incidence (MPX) is helpful in (a) parsing heterogeneity and (b) detecting overlapping and unique underpinnings of the disorders. ASD and ADHD traits were measured in 56 ASD/31 ADHD SPX families, 59 ASD/171 ADHD MPX families and 203 control families.

The reciprocal relationship of ASD, ADHD, depressive symptoms and stress in parents of children with ASD and/or ADHD.

This study investigated the role of parental Autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and depressive symptoms on parenting stress in 174 families with children with ASD and/or ADHD, using generalized linear models and structural equation models. Fathers and mothers reported more stress when parenting with their child with ASD and/or ADHD than when parenting with the unaffected sibling; they also experienced more stress than a norm population. Depressive symptoms were most pronounced in the parents of children with ASD and ASD+ADHD.

Recognition of facial emotion and affective prosody in children with ASD (+ADHD) and their unaffected siblings.

Autism is a highly heritable and clinically heterogeneous neuropsychiatric disorder that frequently co-occurs with other psychopathologies, such as attention-deficit/hyperactivity disorder (ADHD). An approach to parse heterogeneity is by forming more homogeneous subgroups of autism spectrum disorder (ASD) patients based on their underlying, heritable cognitive vulnerabilities (endophenotypes). Emotion recognition is a likely endophenotypic candidate for ASD and possibly for ADHD.

Are parental autism spectrum disorder and/or attention-deficit/Hyperactivity disorder symptoms related to parenting styles in families with ASD (+ADHD) affected children?

An understudied and sensitive topic nowadays is that even subthreshold symptoms of autism spectrum disorder (ASD) and attention-deficit/Hyperactivity disorder (ADHD) in parents may relate to their parenting styles. The aim of this study was to explore the influence of (the combined) effect of child diagnosis (ASD or ASD + ADHD affected/unaffected children) and parental ASD and/or ADHD on parenting styles. Ninety-six families were recruited with one child with a clinical ASD (+ADHD) diagnosis, and one unaffected sibling.

Co-segregation of social cognition, executive function and local processing style in children with ASD, their siblings and normal controls.

Cognitive research proposes that social cognition (SC), executive functions (EF) and local processing style (weak CC) may be fruitful areas for research into the familial-genetic underpinnings of Autism Spectrum Disorders (ASD). The performance of 140 children with ASD, 172 siblings and 127 controls on tasks measuring SC (face recognition, affective prosody, and facial emotion recognition), EF (inhibition, cognitive flexibility, and verbal working memory) and local processing style was assessed. Compelling evidence was found for the interrelatedness of SC and EF, but not local processing style, within individuals and within families, suggesting that these domains tend to co-segregate in ASD.

How to use the ADI-R for classifying autism spectrum disorders? Psychometric properties of criteria from the literature in 1,204 Dutch children.

The algorithm of the Autism Diagnostic Interview-Revised provides criteria for autism versus non-autism according to DSM-IV. Criteria for the broader autism spectrum disorders are needed. This study investigated the validity of seven sets of criteria from the literature, in 1,204 Dutch children (aged 3-18 years) with and without mental retardation.

Match or mismatch? Influence of parental and offspring ASD and ADHD symptoms on the parent-child relationship.

Few studies have examined the influence of parental ASD and ADHD symptoms in combination with child pathology on the parent- child relationship as perceived by the child. A sample of 132 families was recruited with one child with ASD (with/without ADHD), and one unaffected sibling. Affected children (regardless of diagnosis) reported lower acceptance and conflict resolution scores than their unaffected siblings, with conflict resolution scores (but not acceptance) being lower than the norm according to both affected and unaffected children in both fathers and mothers.

Are autism spectrum disorder and attention-deficit/hyperactivity disorder different manifestations of one overarching disorder? Cognitive and symptom evidence from a clinical and population-based sample.

Objective: Autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD) frequently co-occur. Given the heterogeneity of both disorders, several more homogeneous ASD-ADHD comorbidity subgroups may exist. The current study examined whether such subgroups exist, and whether their overlap or distinctiveness in associated comorbid symptoms and cognitive profiles gives support for a gradient overarching disorder hypothesis or a separate disorders hypothesis.

The co-occurrence of autism spectrum disorder and attention-deficit/hyperactivity disorder symptoms in parents of children with ASD or ASD with ADHD.

Background: Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) share about 50-72% of their genetic factors, which is the most likely explanation for their frequent co-occurrence within the same patient or family. An additional or alternative explanation for the co-occurrence may be (cross-)assortative mating, e.g.