Comparative neuropsychology of adult obsessive-compulsive disorder and attention deficit/hyperactivity disorder: Implications for a novel executive overload model of OCD

Research implicates frontostriatal pathophysiology in both attention deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Nevertheless, ADHD is characterized with frontostriatal hypoactivity and OCD with hyperactivity. Furthermore, both disorders seem to lie on opposite ends of a clinical impulsive-compulsive continuum. While never having directly been compared, and despite these differences, OCD and ADHD appear to share similar neuropsychological impairments especially in executive functions. This study aimed at comparing adults with OCD and adults with ADHD on neuropsychological measures and behavioural impulsivity and OC measures. Thirty OCD, 30 ADHD, and 30 matched healthy control (HC) participants were administered a comprehensive neuropsychological battery and completed several questionnaires. The groups were compared on all neuropsychological and clinical measures and correlations between neuropsychological and clinical symptoms were computed. The ADHD and OCD groups performed more poorly than HC on all neuropsychological domains and most domain subtests. The ADHD group reported significantly higher impulsivity than the OCD group. OCD patients did not differ from HC on behavioural impulsivity. A unique dissociation was found between impulsivity and response inhibition where both clinical groups showed similar response inhibition deficit, but differed significantly on impulsivity. Moreover, a negative association between OC symptoms and response inhibition and a bias in self-perception of impulsivity was found only in the OCD group. We propose an executive overload model of OCD that views neuropsychological impairments in OCD as an epiphenomenon, according to which continuous attempts to control automatic processes are associated with obsessive thoughts overflow that causes an overload on the executive system.     

Infectious and immune factors in the pathogenesis of neurodevelopmental disorders: epidemiology, hypotheses, and animal models

Both genetic and environmental factors contribute to the pathogenesis of a wide variety of neurodevelopmental disorders, including autism, mental retardation, and schizophrenia. Some heritable disorders approach 100% penetrance; nonetheless, even in these disorders, subtle aspects of clinical disease expression may be influenced by the environment. In other disorders with genetic influences, exogenous factors, and the timepoint(s) during nervous system development at which they are introduced, modulate expression of disease. Elucidation of the mechanisms guiding this intricate interplay between host response genes, environmental agents, and the neurodevelopmental context within which these interactions occur, is necessary to understand the continuum of clinical outcomes. This chapter will review the evidence that infectious and immune factors may contribute to the pathogenesis of neurodevelopmental disorders, describe an animal model of neurodevelopmental disorders based upon viral infection, identify processes by which neural circuitry may be compromised, and outline areas for future research.     

Lack of association of apolipoprotein E polymorphism in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) could be considered a neurodevelopmental disorder, from several lines of evidence. One of the most widely studied genes in these disorders is the apolipoprotein E gene, particularly allele 4. We analyzed for association among patients with OCD versus normal controls and cognitively impaired patients. There were no significant differences between OCD probands compared with population controls. However, the cognitively impaired group showed a higher frequency of allele apolipoprotein E gene compared with normal controls and patients with OCD.     

Hoarding in obsessive compulsive disorder: results from a case-control study

Hoarding occurs relatively frequently in obsessive-compulsive disorder (OCD), and there is evidence that patients with hoarding symptoms have more severe OCD and are less responsive to treatment. In the present study, we investigated hoarding symptoms in 126 subjects with OCD. Nearly 30% of the subjects had hoarding symptoms; hoarding was twice as prevalent in males than females. Compared to the 90 non-hoarding subjects, the 36 hoarding individuals had an earlier age at onset of, and more severe, obsessive-compulsive symptoms. Hoarders had greater prevalences of symmetry obsessions, counting compulsions, and ordering compulsions. Hoarders also had greater prevalences of social phobia, personality disorders, and pathological grooming behaviors (skin picking, nail biting, and trichotillomania). Hoarding and tics were more frequent in first-degree relatives of hoarding than non-hoarding probands. The findings suggest that the treatment of OCD patients with hoarding symptoms may be complicated by more severe OCD and the presence of co-occurring disorders. Hoarding appears to be transmitted in some OCD families and may differentiate a clinical subgroup of OCD.     

Reexamining the familial association between asthma and ADHD in girls

The objective of this study is to further evaluate the association between asthma and ADHD, addressing issues of familiality in female probands. A case control study of referred ADHD proband girls, controls, and relatives are used. Participants include 140 ADHD proband girls and 122 non-ADHD comparisons, with 417 and 369 first-degree biological relatives, respectively. Relatives are stratified into four groups according to proband ADHD and asthma status. The authors compare rates of asthma and ADHD in relatives. ADHD does not increase the risk for asthma in probands. Patterns of familial aggregation are mostly consistent with independent transmission of ADHD and asthma in families of girl probands. The results extend to female probands' previously reported findings that asthma and ADHD are independently transmitted in families. These findings further support the conclusion that ADHD symptoms should not be dismissed as part of asthma symptomatology or a consequence of its treatment.     

Zur Therapie von ADHS bei komorbiden Autismus-Spektrum-Störungen

Until recently, research on the co-occurrence of ADHD with autism spectrum disorder (ASD) has been limited by the fact that current classification systems did not allow a dual diagnosis of these two neurodevelopmental disorders. Since the DSM-5 permits a double diagnosis of ADHD plus ASD, research on their comorbidity has substantially increased. In addition to shared and distinct etiological factors, studies have revealed a high clinical impact of the combined symptomatology on affected individuals. This article provides a selective overview of evidence-based, mainly pharmacological treatment strategies in ADHD/ASD phenotypes.     

Hoarding in obsessive-compulsive disorder: results from the OCD Collaborative Genetics Study

Hoarding behavior occurs frequently in obsessive-compulsive disorder (OCD). Results from previous studies suggest that individuals with OCD who have hoarding symptoms are clinically different than non-hoarders and may represent a distinct clinical group. In the present study, we compared 235 hoarding to 389 non-hoarding participants, all of whom had OCD, collected in the course of the OCD Collaborative Genetics Study. We found that, compared to non-hoarding individuals, hoarders were more likely to have symmetry obsessions and repeating, counting, and ordering compulsions; poorer insight; more severe illness; difficulty initiating or completing tasks; and indecision. Hoarders had a greater prevalence of social phobia and generalized anxiety disorder. Hoarders also had a greater prevalence of obsessive-compulsive and dependent personality disorders. Five personality traits were independently associated with hoarding: miserliness, preoccupation with details, difficulty making decisions, odd behavior or appearance, and magical thinking. Hoarding and indecision were more prevalent in the relatives of hoarding than of non-hoarding probands. Hoarding in relatives was associated with indecision in probands, independently of proband hoarding status. The findings suggest that hoarding behavior may help differentiate a distinct clinical subgroup of people with OCD and may aggregate in some OCD families. Indecision may be a risk factor for hoarding in these families.     

Does comorbid attention-deficit/hyperactivity disorder impact the clinical expression of pediatric obsessive-compulsive disorder?

What is the impact of attention-deficit/hyperactivity disorder (ADHD) on the phenotypic expression of pediatric obsessive-compulsive disorder (OCD). We examined phenotypic features, and functional and clinical correlates in youths with OCD, with and without comorbid ADHD, from a large sample of consecutively referred pediatric psychiatry patients. Although comorbid ADHD had no meaningful impact on the phenotypic expression or clinical correlates of OCD, it was associated with higher rates of compromised educational functioning compared with other OCD youths. Our findings suggest that the OCD phenotype runs true and is not impacted by comorbid ADHD in youths diagnosed with both OCD and ADHD. In such affected youths, both disorders contribute to morbid dysfunction and require treatment. More work is needed to determine whether OCD plus ADHD represents a developmentally and etiologically distinct form of the OCD syndrome.     

Neurocognitive Performance in Children with ADHD and OCD

Attention-deficit/hyperactivity Disorder (ADHD) and obsessive–compulsive disorder (OCD) have both been linked to dysfunction in the cortico-striato-thalamo-cortical circuitry (CSTCC). However, the exact nature of neurocognitive deficits remains to be investigated in both disorders. We applied two neuropsychological tasks that tap into different functions associated with the CSTCC, namely a serial reaction time (SRT) task, developed to assess implicit sequence learning, and a delay aversion (DA) task in order to assess abnormal motivational processes. The performance data of boys with ADHD (n = 20), OCD (n = 20) and healthy controls (n = 25), all aged 10–18 years, were compared. Subjects with ADHD less frequently chose the larger, more delayed reward compared to those with OCD and controls, while subjects with OCD showed impaired implicit learning. In contrast, the ADHD group was unimpaired in their implicit learning behavior and the OCD group was not characterized by a DA style. Within the OCD-group, severity of obsessions was associated with implicit learning deficits and impulsive symptoms with DA in the ADHD-group. This double dissociation highlights the distinct cognitive dysfunctions associated with ADHD and OCD and might possibly point to different neural abnormalities in both disorders.     

Local-global processing in obsessive-compulsive disorder and comorbid Tourette's syndrome

Neuropsychological and neuroimaging studies implicate attentional difficulties in obsessive-compulsive disorder (OCD), but results are inconsistent due possibly to sample heterogeneity and lack of control of comorbid disorders, such as Tourette's syndrome (TS). Nevertheless, it has been suggested that OCD symptomatology may be a result of over-focused attention at a local level. Therefore, this study aimed to examine the ability of OCD patients (pure and comorbid OCD + TS) to process local and global stimuli. Using a local-global paradigm, participants were required to respond to the directed level (local or global) of various stimuli. Results indicate that pure OCD participants were impaired on the global task, whereas comorbid OCD + TS participants had difficulty processing local information. Results are consistent with previously reported lateralisation anomalies and suggest that OCD negatively affects the ability to process hierarchically presented stimuli.     

A family study of outpatients with borderline personality disorder and no history of mood disorder

While several studies have examined psychiatric disorders in the relatives of individuals with borderline personality disorder, many of these studies have not employed a family study methodology and suffer from other methodological shortcomings. Thus, the conclusions from family data addressing the validity of borderline personality disorder, its relation to other conditions, and its distinction from mood disorders, continue to be debated. The present investigation employed a family study design with direct interviews with relatives, structured diagnostic interviews with both probands and relatives, and blind assessment of relatives. Rates of psychiatric disorders were examined in 563 relatives of outpatients with mood disorders (n = 119), 54 relatives of outpatients with borderline personality disorder and no history of mood disorder (n = 11), and 229 relatives of never psychiatrically ill controls (n = 45). Results indicate increased rates of mood disorders and personality disorders in the relatives of borderline probands compared with never psychiatrically ill controls. Familial aggregation of psychiatric disorders was generally similar for borderline personality and the mood disorder comparison group. The results suggest there may be common etiological factors between borderline personality disorder and mood disorders.     

基于时间顺序的多动症共病的概述

多动症是一种常见的行为障碍,它以注意力不集中、多动、行为冲动为主要特征。同时多动症是一组异质性疾病,常与一种或几种精神或非精神障碍相伴发生。以往关于多动症合并症状的研究,大都局限在一个或几个合并症状上,缺乏关于其合并症状的系统认识。基于以往研究,文章以多动症合并症状发生的时间顺序为线索,将其分为前期、同期、后期合并症,并逐一详细介绍。未来应该加强关于多动症患者的纵向研究,以了解症状的发展状况,更好的诊断和治疗多动症。     

Exploring the Possibility of Shared Familial Diathesis for Personality in OCD Probands

The present study aims to probe into the status of the big five personality factors in the OCD probands and their first degree relatives (FDR) viz a viz community controls and also look into the association of the big five factors with symptom severity and obsessive personality traits. Fifty dyads of probands and FDR and community controls matched on the basis of age, sex and education were assessed on NEO Five Factor Inventory, Yale Brown Obsession Compulsion Scale, Beck Depression Inventory and Leyton Obsessional Inventory to fulfill the aims of the study. The findings reveal higher neuroticism and lower extroversion and conscientiousness in the OCD group as compared to controls, endorsement of greater conscientiousness among the FDR as compared to the case-probands, with Agreeableness and Conscientiousness emerging as predictors associated with obsessive symptoms among OCD probands.     

The semantic Simon effect in Tourette's syndrome and obsessive-compulsive disorder

Core symptoms of Tourette's syndrome (TS) and obsessive-compulsive disorder (OCD) may be attributed to an impairment in inhibitory control. Neuropsychological studies have addressed inhibition in both disorders, but findings have been inconsistent. The aim of this study was to examine cognitive inhibition, using a semantic Simon effect paradigm, in patients with TS and OCD. Furthermore, to address comorbidity a group of TS+OCD patients was also examined. Results indicated that patients with TS and OCD were affected by the inhibitory components of the task. TS groups performed similarly to controls on simple and choice RT tasks, but were particularly compromised as increasingly complex inhibitory demands were imposed. OCD patients were slower and committed more errors than controls, especially in the more cognitively demanding conditions, and were particularly disadvantaged by incongruent stimulus-response compatibilities. Findings implicate possible fronto-striatal dysfunction, are consistent with previously reported inhibitory deficits in TS and OCD, and support the theory that comorbid TS+OCD is more closely linked to pure TS than OCD.     

Variability in Adaptive Behavior in Autism: Evidence for the Importance of Family History

Adaptive behavior in autism is highly variable and strongly related to prognosis. This study explored family history as a potential source of variability in adaptive behavior in autism. Participants included 77 individuals (mean age = 18) with average or better intellectual ability and autism. Parents completed the Family History Interview about the presence of broader autism phenotype symptoms and major psychiatric disorders in first degree relatives. Adaptive behavior was assessed via the Vineland Adaptive Behavior Scales (VABS). Based on family history variables, age, and intelligence quotient (IQ), 87% of participants were correctly classified as having impaired or average VABS scores. Family history of depression and shyness accounted for the most variance in VABS scores, and they had the greatest influence on VABS Socialization scores in particular. Possible underlying mechanisms include genetics, psychosocial factors, and social resources. This study provides initial evidence of the importance of family history to adaptive behavior in autism and has implications for genetics and treatment.     

Autistic Traits Below the Clinical Threshold: Re-examining the Broader Autism Phenotype in the 21st Century

Diagnosis, intervention and support for people with autism can be assisted by research into the aetiology of the condition. Twin and family studies indicate that autism spectrum conditions are highly heritable; genetic relatives of people with autism often show milder expression of traits characteristic for autism, referred to as the Broader Autism Phenotype (BAP). In the past decade, advances in the biological and behavioural sciences have facilitated a more thorough examination of the BAP from multiple levels of analysis. Here, the candidate phenotypic traits delineating the BAP are summarised, including key findings from neuroimaging studies examining the neural substrates of the BAP. We conclude by reviewing the value of further research into the BAP, with an emphasis on deriving heritable endophenotypes which will reliably index autism susceptibility and offer neurodevelopmental mechanisms that bridge the gap between genes and a clinical autism diagnosis.     

Genetics of autism spectrum disorders

Characterized by a combination of abnormalities in language, social cognition and mental flexibility, autism is not a single disorder but a neurodevelopmental syndrome commonly referred to as autism spectrum disorder (ASD). Several dozen ASD susceptibility genes have been identified in the past decade, collectively accounting for 10-20% of ASD cases. These findings, although demonstrating that ASD is etiologically heterogeneous, provide important clues about its pathophysiology. Diverse genetic and genomic approaches provide evidence converging on disruption of key biological pathways, many of which are also implicated in other allied neurodevelopmental disorders. Knowing the genes involved in ASD provides us with a crucial tool to probe both the specificity of ASD and the shared neurobiological and cognitive features across what are considered clinically distinct disorders, with the goal of linking gene to brain circuits to cognitive function.     

Executive and Attention Functioning Among Children in the PANDAS Subgroup

Evidence from past studies indicates that adults and children with Obsessive-Compulsive Disorder (OCD) and Tourette syndrome (TS) experience subtle neuropsychological deficits. Less is known about neuropsychological functioning of children and adolescents with a symptom course consistent with the PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infection) subgroup of OCD and tics. To provide such information, we administered three tests of attention control and two of executive function to 67 children and adolescents (ages 5–16) diagnosed with OCD and/or tics and a symptom course consistent with the PANDAS subgroup and 98 healthy volunteers (HV) matched by age, sex, and IQ. In a paired comparison of the two groups, the PANDAS subjects were less accurate than HV in a test of response suppression. Further, in a two-step linear regression analysis of the PANDAS group in which clinical variables were added stepwise into the model and in the second step matching variables (age, sex, and IQ) were added, IQ emerged as a predictor of performance on this task. In the same analysis, ADHD diagnosis and age emerged as predictors of response time in a continuous performance task. Subdividing the PANDAS group by primary psychiatric diagnosis revealed that subjects with TS or OCD with tics exhibited a longer response time compared to controls than subjects with OCD only, replicating previous findings within TS and OCD. This study demonstrates that children with PANDAS exhibit neuropsychological profiles similar to those of their primary psychiatric diagnosis.     

Speed and accuracy on tests of executive function in obsessive-compulsive disorder

Slowness in obsessive-compulsive disorder (OCD) has been attributed to intrusive thoughts or meticulousness. Recent research suggests that slowness in OCD may be particularly evident on tests of executive function subserved by frontostriatal circuitry. In the present study, the speed and accuracy of responding on neuropsychological tests of executive functions and psychomotor speed were investigated in 27 non-depressed, unmedicated adults with OCD and 27 healthy controls. The only group difference was that patients took significantly longer to copy a complex geometric design than controls. This finding was unrelated to residual depression or overall OCD symptom severity. Results suggest that slowness in OCD may be most apparent on executive tests requiring self-initiated organizational strategies, consistent with frontostriatal abnormality.