The neurobiological link between OCD and ADHD

Increased decision thresholds enhance information gathering performance in juvenile Obsessive-Compulsive Disorder (OCD)

Patients with obsessive-compulsive disorder (OCD) can be described as cautious and hesitant, manifesting an excessive indecisiveness that hinders efficient decision making. However, excess caution in decision making may also lead to better performance in specific situations where the cost of extended deliberation is small. We compared 16 juvenile OCD patients with 16 matched healthy controls whilst they performed a sequential information gathering task under different external cost conditions. We found that patients with OCD outperformed healthy controls, winning significantly more points. The groups also differed in the number of draws required prior to committing to a decision, but not in decision accuracy. A novel Bayesian computational model revealed that subjective sampling costs arose as a non-linear function of sampling, closely resembling an escalating urgency signal. Group difference in performance was best explained by a later emergence of these subjective costs in the OCD group, also evident in an increased decision threshold. Our findings present a novel computational model and suggest that enhanced information gathering in OCD can be accounted for by a higher decision threshold arising out of an altered perception of costs that, in some specific contexts, may be advantageous.

Methylphenidate in the treatment of an adolescent female with obsessive-compulsive disorder and attention deficit hyperactivity disorder: a case report

OBJECTIVES

We describe a case whereby a 15-year-old female with treatment-resistant obsessive-compulsive disorder (OCD) was treated with methylphenidate for co-morbid attention deficit hyperactivity disorder (ADHD). The ADHD-OCD co-morbidity has often been overlooked clinically due to conflicting opinions about their underlying neurobiology and treatment options.

CONCLUSIONS

In this adolescent with co-morbid ADHD and OCD, we observed that the adjunctive use of methylphenidate resulted in enhanced treatment response to both psychological and pharmacological interventions for OCD. This case highlights the need to identify and treat co-morbid ADHD in OCD cases where progress has stalled.

Genome Wide Association Study (GWAS) between Attention Deficit Hyperactivity Disorder (ADHD) and Obsessive Compulsive Disorder (OCD)

Objective: The aim of this study was to identify any potential genetic overlap between attention deficit hyperactivity disorder (ADHD) and obsessive compulsive disorder (OCD). We hypothesized that since these disorders share a sub-phenotype, they may share common risk alleles. In this manuscript, we report the overlap found between these two disorders. Methods: A meta-analysis was conducted between ADHD and OCD, and polygenic risk scores (PRS) were calculated for both disorders. In addition, a protein-protein analysis was completed in order to examine the interactions between proteins; p-values for the protein-protein interaction analysis was calculated using permutation. Conclusion: None of the single nucleotide polymorphisms (SNPs) reached genome wide significance and there was little evidence of genetic overlap between ADHD and OCD.

Association of GRIN2B gene polymorphism and Obsessive Compulsive disorder and symptom dimensions: A pilot study

The etiology of OCD is largely unknown, but neuroimaging and pharmacological studies suggest that glutamatergic system plays a significant role on OCD development. We genotyped one polymorphism at GRIN2B (rs1019385) by real time Polymerase Chain Reaction in a sample of Brazilian Obsessive-Compulsive patients and healthy controls, and evaluated its influence on OCD. We found the T-allele and TT genotype to be significantly associated with OCD and ordering dimension. The T-allele was also significantly associated with checking. These preliminary results demonstrated that the GRIN2B gene may confer to some extent the susceptibility to OCD and its symptoms.

Clinical significance of psychiatric comorbidity in children and adolescents with obsessive-compulsive disorder: subtyping a complex disorder

A promising approach in relation to reducing phenotypic heterogeneity involves the identification of homogeneous subtypes of OCD based on age of onset, gender, clinical course and comorbidity. This study aims to assess the sociodemographic characteristics and clinical features of OCD patients in relation to gender and the presence or absence of another comorbid disorder. The sample comprised 112 children and adolescents of both sexes and aged 8-18 years, all of whom had a diagnosis of OCD. Overall, 67 % of OCD patients had one comorbid diagnosis, 20.5 % had two such diagnoses and 2.6 % had three comorbid diagnoses. The group of OCD patients with a comorbid neurodevelopmental disorder had significantly more family history of OCD in parents (p = .049), as compared with the no comorbidity group and the group with a comorbid internalizing disorder, and they also showed a greater predominance of males (p = .013) than did the group with a comorbid internalizing disorder. The group of OCD patients with internalizing comorbidity had a later age of onset of OCD (p = .001) compared with both the other groups. Although the initial severity was similar in all three groups, the need for pharmacological treatment and for hospitalization due to OCD symptomatology was greater in the groups with a comorbid neurodevelopmental disorder (p = .038 and p = .009, respectively) and a comorbid internalizing disorder (p = .008 and p = .004, respectively) than in the group without comorbidity. Our findings suggest that two subtypes of OCD can be defined on the basis of the comorbid pathology presented. The identification of different subtypes according to comorbidity is potentially useful in terms of understanding clinical variations, as well as in relation to treatment management and the use of therapeutic resources.

Treatment Efficacy of Combined Sertraline and Guanfacine in Comorbid Obsessive-Compulsive Disorder and Attention Deficit/Hyperactivity Disorder: Two Case Studies

OBJECTIVE

Treatment of obsessive-compulsive disorder (OCD) is complicated by comorbid psychiatric disorders. Successful treatment of 2 pediatric patients with severe OCD and comorbid attention deficit/hyperactivity disorder (ADHD) is described.

METHOD

A report on 2 pediatric clinical cases (Ages 9 and 10) with comorbid OCD and ADHD was used to describe response to medication management through the serotonin transporter inhibitor, sertraline, and the noradrenergic α2A receptor agonist, guanfacine, along with cognitive behavioral therapy.

RESULTS

Cognitive behavioral therapy combined with titrated doses of the serotonin transporter inhibitor, sertraline, and the noradrenergic α2A receptor agonist, guanfacine resolved OCD symptoms and the underlying ADHD.

CONCLUSION

The novel observations support a focused psychological and pharmacological approach to successful treatment of complex symptoms in patients with comorbid OCD and ADHD. Limitations to generalizability are discussed.

Imaging genetics in obsessive-compulsive disorder: linking genetic variations to alterations in neuroimaging

Obsessive-compulsive disorder (OCD) occurs in ∼1-3% of the general population, and its often rather early onset causes major disabilities in the everyday lives of patients. Although the heritability of OCD is between 35 and 65%, many linkage, association, and genome-wide association studies have failed to identify single genes that exhibit high effect sizes. Several neuroimaging studies have revealed structural and functional alterations mainly in cortico-striato-thalamic loops. However, there is also marked heterogeneity across studies. These inconsistencies in genetic and neuroimaging studies may be due to the heterogeneous and complex phenotypes of OCD. Under the consideration that genetic variants may also influence neuroimaging in OCD, researchers have started to combine both domains in the field of imaging genetics. Here, we conducted a systematic search of PubMed and Google Scholar literature for articles that address genetic imaging in OCD and related disorders (published through March 2014). We selected 8 publications that describe the combination of imaging genetics with OCD, and extended it with 43 publications of comorbid psychiatric disorders. The most promising findings of this systematic review point to the involvement of variants in genes involved in the serotonergic (5-HTTLPR, HTR2A), dopaminergic (COMT, DAT), and glutamatergic (SLC1A1, SAPAP) systems. However, the field of imaging genetics must be further explored, best through investigations that combine multimodal imaging techniques with genetic profiling, particularly profiling techniques that employ polygenetic approaches, with much larger sample sizes than have been used up to now.