Neuropsychological Functioning, Symptom Dimensions and Cognitive Remediation in Obsessive-Compulsive Disorder

Abstract

Objectives: The first objective of this research was to examine whether symptom dimensions in obsessive-compulsive disorder (OCD) are associated with unique neuropsychological performance profiles. The second objective of this research was to further understand the strengths and weaknesses of two models of symptom dimensions in OCD from a quantitative perspective—conventional subtyping by overt symptom, and the core dimensions model. Finally, the third objective of this research was to investigate the efficacy and treatment acceptability of a cognitive remediation program targeting neurocognitive deficits associated with OCD. Methods: Study 1 reviewed critically studies describing the assessment of differences in neuropsychological functioning between symptom dimensions of OCD, the results of which informed succeeding studies examining: i) the characterization of symptom dimensions in OCD and; ii) the remediation of neuropsychological domains commonly affected in OCD. Accordingly, study 2 compared the suitability of two common statistical approaches, factor analysis and cluster analysis, commonly used in the existing literature to define symptom dimensions based on responses collected from the industry-standard symptom questionnaire, the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), in characterizing symptom dimensions in OCD. Neuropsychological task data were then used to examine the validity of an alternative model of symptom dimensions in OCD (Study 3). Finally, we conducted a feasibility study (Study 4) examining the use of an established cognitive remediation protocol, Goal Management Training (GMT), to target the deficits in neurocognitive function identified in the preceding studies. Results: Much of the existing literature on neuropsychological task performance differences between symptom dimensions of OCD is limited by methodological issues, primarily those concerning methods for defining symptom dimensions. Here, a comparison of the two most common methods for defining dimensions revealed that neither cluster analysis nor factor analysis produced conceptually meaningful subgroups. By exemplifying differences in neuropsychological task performance between those with harm avoidance and those with incompleteness symptoms, however, concrete evidence was provided to support the core dimensions model of OCD. Pilot data point towards the feasibility and efficacy of GMT as a cognitive remediation program for OCD. Conclusions: Pursuing the definition of meaningful, distinct symptom dimensions of OCD is not recommended with the combination of current statistical practices and symptom measures. The early evidence presented here shows promise for the validity of the core dimensions model. Preliminary evidence suggests that the neuropsychological impairments observed in this population, although subtle, may be effectively addressed using Goal Management Training.