Neurocircuit models of obsessive-compulsive disorder: limitations and future directions for research

Obsessive-compulsive disorder (OCD) is a common psychiatric condition classically characterized by obsessions (recurrent, intrusive and unwanted thoughts) and compulsions (excessive, repetitive and ritualistic behaviors or mental acts). OCD is heterogeneous in its clinical presentation and not all patients respond to first-line treatments. Several neurocircuit models of OCD have been proposed with the aim of providing a better understanding of the neural and cognitive mechanisms involved in the disorder. These models use advances in neuroscience and findings from neuropsychological and neuroimaging studies to suggest links between clinical profiles that reflect the symptoms and experiences of patients and dysfunctions in specific neurocircuits. Several models propose that treatments for OCD could be improved if directed to specific neurocircuit dysfunctions, thereby restoring efficient neurocognitive function and ameliorating the symptomatology of each associated clinical profile. Yet, there are several important limitations to neurocircuit models of OCD. The purpose of the current review is to highlight some of these limitations, including issues related to the complexity of brain and cognitive function, the clinical presentation and course of OCD, etiological factors, and treatment methods proposed by the models. We also provide suggestions for future research to advance neurocircuit models of OCD and facilitate translation to clinical application.

Factor structure of the Dimensional Yale-Brown Obsessive-Compulsive Scale in a large sample of adults with obsessive-compulsive disorder

Objectives: Although the Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS) is a widely used instrument for assessing different obsessive-compulsive symptom dimensions, its factor structure has never been studied in a Brazilian population. Thus, we aimed to assess the goodness-of-fit indexes and factor loadings of two higher-order models of the DY-BOCS using confirmatory factor analysis (CFA) in a large obsessive-compulsive disorder (OCD) sample. Methods: We tested two CFA models in a sample of 955 adults with OCD who had been assessed with the DY-BOCS in a cross-sectional multi-site study. The first model encompassed the symptom checklist (present or absent), whereas the second focused on items related to severity scores. Results: Both models presented adequate goodness-of-fit indexes. The comparative fit index, Tucker-Lewis index, and omega were > 0.9, while the root mean square error of approximation was ≤ 0.06 for both models. Factor loadings for each item of each dimension are presented and discussed. Conclusion: Higher-order factor models showed adequate goodness-of-fit indexes, indicating that they appropriately measured OCD dimensions in this Brazilian population.

No evidence of attentional bias toward angry faces in patients with obsessive-compulsive disorder

Objective: Although attentional bias (AB) toward angry faces is well established in patients with anxiety disorders, it is still poorly studied in obsessive-compulsive disorder (OCD). We investigated whether OCD patients present AB toward angry faces, whether AB is related to symptom severity and whether AB scores are associated with specific OCD symptom dimensions. Method: Forty-eight OCD patients were assessed in clinical evaluations, intelligence testing and a dot-probe AB paradigm that used neutral and angry faces as stimuli. Analyses were performed with a one-sample t-test, Pearson correlations and linear regression. Results: No evidence of AB was observed in OCD patients, nor was there any association between AB and symptom severity or dimension. Psychiatric comorbidity did not affect our results. Conclusion: In accordance with previous studies, we were unable to detect AB in OCD patients. To investigate whether OCD patients have different brain activation patterns from anxiety disorder patients, future studies using a transdiagnostic approach should evaluate AB in OCD and anxiety disorder patients as they perform AB tasks under functional neuroimaging protocols.

Obsessive-compulsive symptoms in children with first degree relatives diagnosed with obsessive-compulsive disorder

Objective: A first-degree relative affected by obsessive-compulsive disorder (OCD) and obsessive-compulsive symptoms (OCS) in childhood is an important risk factor for developing the disorder in adulthood. The relationship between a family history of OCD and the presence of OCS and its correlates in childhood is not well established. Methods: A total of 66 children whose parents or siblings have been diagnosed with OCD were assessed for the presence of OCS and clinical correlates. Results: Three children (4.5%) were reported to have received an OCD diagnosis and another 26 (39.4%) were identified as having OCS. Children with OCS had higher rates of coercive behavior and came from families with lower socioeconomic status. Contamination/cleaning dimension symptoms in the proband were associated with OCS in the assessed children. Conclusion: OCS are frequent among family members of individuals with OCD and are associated with socioeconomic status, coercive behaviors and proband contamination/cleaning symptoms. Future longitudinal studies should test the risk of developing OCD in association with these characteristics.

Brain regions supporting verbal memory improvement in healthy older subjects / Regiões do cérebro relacionadas à melhora da memória verbal em idosos saudáveis

Despite growing interest in developing cognitive training interventions to minimize the aging cognitive decline process, no studies have attempted to explore which brain regions support the application of semantic strategies during verbal memory encoding. Our aim was to investigate the behavioral performance and brain correlates of these strategies in elderly individuals using fMRI in healthy older subjects. Method Subjects were scanned twice on the same day, before and after, directed instructions to apply semantic strategies during the encoding of word lists. Results Improved memory performance associated to increased semantic strategy application and brain activity in the left inferior and middle and right medial superior prefrontal cortex were found after the directed instructions. There was also reduced activation in areas related to strategy mobilization. Conclusion Improved memory performance in older subjects after the application of semantic strategies was associated with functional brain reorganization involving regions inside and outside the typical memory network. .

Apesar do crescente interesse em intervenções de treinamento cognitivo para minimizar o declínio cognitivo do envelhecimento, nenhum estudo explorou quais regiões do cérebro estão relacionadas à aplicação de estratégias semânticas durante a codificação da memória verbal. Nosso objetivo foi investigar o comportamento e correlatos cerebrais associados a essas estratégias usando fMRI em idosos saudáveis. Método Os sujeitos foram examinados no mesmo dia, antes e depois, de instruções dirigidas para aplicar estratégias semânticas durante a codificação de palavras. Resultados Melhora da memória relacionada ao uso de estratégias semânticas e aumento da atividade no córtex prefrontal inferior e medial esquerdo e medial superior direito foram encontrados após as instruções. Também houve redução de ativação em áreas de mobilização de estratégias. Conclusão A melhora da memória em idosos após o uso de estratégias semânticas estava associada à reorganização cerebral funcional envolvendo regiões dentro e fora da rede de áreas cerebrais típicas da memória. .

Outlining new frontiers for the comprehension of obsessive-compulsive disorder: a review of its relationship with fear and anxiety / Desenhando as novas fronteiras para a compreensão do transtorno obsessivo-compulsivo: uma revisão de sua relação com o medo e a ansiedade

Anxiety is an important component of the psychopathology of the obsessive-compulsive disorder (OCD). So far, most interventions that have proven to be effective for treating OCD are similar to those developed for other anxiety disorders. However, neurobiological studies of OCD came to conclusions that are not always compatible with those previously associated with other anxiety disorders. OBJECTIVES: The aim of this study is to review the degree of overlap between OCD and other anxiety disorders phenomenology and pathophysiology to support the rationale that guides research in this field. RESULTS: Clues about the neurocircuits involved in the manifestation of anxiety disorders have been obtained through the study of animal anxiety models, and structural and functional neuroimaging in humans. These investigations suggest that in OCD, in addition to dysfunction in cortico-striatal pathways, the functioning of an alternative neurocircuitry, which involves amygdalo-cortical interactions and participates in fear conditioning and extinction processes, may be impaired. CONCLUSION: It is likely that anxiety is a relevant dimension of OCD that impacts on other features of this disorder. Therefore, future studies may benefit from the investigation of the expression of fear and anxiety by OCD patients according to their type of obsessions and compulsions, age of OCD onset, comorbidities, and patterns of treatment response.

A ansiedade é um componente importante da psicopatologia do transtorno obsessivo-compulsivo (TOC). Até o momento, a maioria das intervenções que provaram ser eficazes para o tratamento de TOC é semelhante àquelas desenvolvidas para outros transtornos de ansiedade. No entanto, estudos que investigaram a neurobiologia do TOC chegaram a conclusões que nem sempre são compatíveis com aquelas anteriormente associadas aos demais transtornos de ansiedade. OBJETIVOS: Neste artigo, revisamos o grau de sobreposição entre as características do TOC e a fenomenologia e fisiopatologia dos demais transtornos de ansiedade com o intuito de dar suporte ao racional que orienta a pesquisa nesse campo. RESULTADOS: Alguns dados sobre os neurocircuitos envolvidos na manifestação dos transtornos de ansiedade foram obtidos a partir do estudo de modelos animais de ansiedade, e da neuroimagem estrutural e funcional em humanos. Esses trabalhos sugerem que no TOC, além da disfunção das vias corticoestriatais, o funcionamento do circuito amigdalocortical, essencial para a apresentação da resposta de medo e processos de extinção dessa resposta, também pode estar prejudicado. CONCLUSÃO: É provável que a ansiedade seja uma dimensão relevante do TOC, com impacto em outras características desse transtorno. Consequentemente, estudos futuros podem se beneficiar da investigação dos fenômenos de medo e ansiedade e de suas relações com os tipos de obsessões e compulsões, idade de início do TOC, comorbidades e padrões de resposta ao tratamento.

The drug-naïve OCD patients imaging genetics, cognitive and treatment response study: methods and sample description / Estudo de genética, imagem, cognição e resposta a tratamento em pacientes com TOC virgens de tratamento: métodos e descrição da amostra

OBJECTIVE: To describe a protocol that was based on an integrative neurobiological model of scientific investigation to better understand the pathophysiology of obsessive-compulsive disorder and to present the clinical and demographic characteristics of the sample. METHOD: A standardized research protocol that combines different methods of investigation (genetics, neuropsychology, morphometric magnetic resonance imaging and molecular neuroimaging of the dopamine transporter) obtained before and after treatment of drug-naïve adult obsessive-compulsive disorder patients submitted to a sequentially allocated 12-week clinical trial with a selective serotonin reuptake inhibitor (fluoxetine) and group cognitive-behavioral therapy. RESULTS: Fifty-two treatment-naïve obsessive-compulsive disorder patients entered the clinical trial (27 received fluoxetine and 25 received group cognitive-behavioral therapy). At baseline, 47 blood samples for genetic studies, 50 neuropsychological evaluations, 50 morphometrical magnetic resonance images and 48 TRODAT-1 single-photon emission computed tomography (SPECT) exams were obtained. After 12 weeks, 38 patients completed the protocol (fluoxetine = 20 and GCBT = 18). Thirty-eight neuropsychological evaluations, 31 morphometrical magnetic resonance images and 34 TRODAT-1 SPECT exams were obtained post-treatment. Forty-one healthy controls matched for age, gender, socioeconomic status, level of education and laterality were submitted to the same research procedures at baseline. CONCLUSION: The comprehensive treatment response protocol applied in this project allowing integration on genetic, neuropsychological, morphometrical and molecular imaging of the dopamine transporter data in drug-naïve patients has the potential to generate important original information on the neurobiology of obsessive-compulsive disorder, and at the same time be clinically meaningful.

OBJETIVO: Descrever um protocolo integrativo de investigação neurobiológica para melhor compreender as bases patofisiológicas do transtorno obsessivo-compulsivo e apresentar as características clínicas e demográficas da amostra. MÉTODO: Protocolo padronizado que combina diferentes modalidades de investigação (genética, neuropsicologia, ressonância magnética cerebral e imagem molecular do transportador de dopamina) obtidas antes e depois do tratamento em pacientes com transtorno obsessivo-compulsivo nunca expostos à medicação submetidos a um ensaio clínico comparando um inibidor seletivo da recaptação de serotonina (fluoxetina) e terapia cognitivo-comportamental em grupo. RESULTADOS: Cinquenta e dois pacientes com transtorno obsessivo-compulsivo entraram no ensaio clínico (27 no grupo fluoxetina e 25 no grupo de terapia). No início, foram realizadas 47 coletas de sangue para genética, 50 avaliações neuropsicológicas, 50 ressonâncias magnéticas cerebrais e 48 exames de tomografia computadorizada por emissão de fóton único (SPECT) com TRODAT-1. Depois de 12 semanas, 38 pacientes terminaram o protocolo (20 no grupo de fluoxetina e 18 no grupo de terapia). Trinta e oito reavaliações neuropsicológicas, 31 ressonâncias magnéticas de crânio e 34 exames de SPECT foram obtidos após o tratamento. Quarenta e um controles pareados foram submetidos ao mesmo protocolo inicial. CONCLUSÃO: Os dados genéticos, neuropsicológicos, volumétricos e moleculares do transportador de dopamina aliados à resposta a tratamento podem tanto gerar informações importantes a respeito da neurobiologia do transtorno obsessivo-compulsivo quanto ter uma aplicação clínica.