|Year : 2017 | Volume
| Issue : 1 | Page : 55-60
Visuospatial memory in patients with obsessive-compulsive disorder
Anamika Sahu1, Basudeb Das2, Preeti Gupta2
1 Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India
2 Central Institute of Psychiatry, Ranchi, Jharkhand, India
|Date of Web Publication||14-Jul-2017|
Room No. 4089, Department of Psychiatry, All India Institute of Medical Sciences, New Delhi
Source of Support: None, Conflict of Interest: None
Background: Obsessive-compulsive disorder (OCD) is a clinically heterogeneous disorder. The previous studies have been conducted to elucidate visuospatial and nonverbal memory deficits in OCD patients. However, they did not reach equivocal results which need to be replicated. Objectives: The current study examines the visuospatial memory in male patients with OCD as compared to normal healthy controls. Materials and Methods: It is a cross-sectional hospital-based study, in which 15 OCD patients and 15 age-, sex-, and education-matched normal healthy controls were chosen by purposive sampling technique. All the participants underwent the Extended Complex Figure Test (ECFT) for the assessment of visuospatial memory. Results: Significant difference was found between OCD patients and normal healthy controls on various domains of ECFT. OCD patients performed poorly on copy condition (t = −4.46; P< 0.001), immediate recall (t = −5.20; P< 0.001), delayed recall (t = −5.18; P< 0.001), recognition task (P < 0.001), and matching task (P < 0.001) than the controls. Conclusion: Visuospatial memory was significantly impaired in OCD that included disturbed encoding and impaired visuospatial functioning. Hence, it is important to understand the significance of visuospatial memory in the pathophysiology for OCD diagnosis and therapeutic decision.
Keywords: Nonverbal memory, obsessive-compulsive disorder, visuospatial memory
|How to cite this article:|
Sahu A, Das B, Gupta P. Visuospatial memory in patients with obsessive-compulsive disorder. J Mental Health Hum Behav 2017;22:55-60
|How to cite this URL:|
Sahu A, Das B, Gupta P. Visuospatial memory in patients with obsessive-compulsive disorder. J Mental Health Hum Behav [serial online] 2017 [cited 2021 May 13];22:55-60. Available from: https://www.jmhhb.org/text.asp?2017/22/1/55/210707
| Introduction|| |
Obsessive-compulsive disorder (OCD) is an often disabling condition, characterized by recurrent, intrusive thoughts (i.e., obsessions) and repetitive and stereotypical rituals (i.e., compulsions) that interfere with daily functions and cause significant distress. OCD is considered twice as prevalent as schizophrenia or bipolar disorder, with a worldwide prevalence of 1.5%–3%.,
Both structural and functional neuroimaging studies suggested the involvement of neurobiological abnormalities in the pathogenesis of OCD. A neurobiological model of OCD, i.e., frontostriatal model, provides evidence for an abnormal neuronal activity in the orbitofrontal cortex, anterior cingulate cortex, dorsolateral prefrontal cortex, caudate nucleus, and thalamus.,, In addition, neuropsychological impairments in individual with OCD have been documented in previous studies, for example, problem with memory,,,,,,,, visuospatial skills,,,,,,,, visual attention,, and selective executive functions.,,,,,,,,,,
Impaired visuospatial and nonverbal memory play a crucial role in the pathogenesis of OCD.,, Visuospatial disturbance may stem from alteration of the right hemisphere, i.e. detected in neuroimaging studies of OCD  and organizational difficulties. Furthermore, primary and acquired focal dysfunctions in the right hemisphere and the subcortex are implicated in the pathogenesis of OCD  which can produce isolated dysfunction in some components of visuospatial memory.
Studies considering visuospatial memory in OCD did not reach equivocal results. Where the majority of studies have been verified impaired visuospatial memory in OCD, others were unable to find group differences.,,, It could be because of variation in OCD symptomatology, comorbid conditions, variation of task presentation, etc. In the Indian context, few studies have been done on neuropsychological profile and its correlates in OCD.,,,,, However, they were limited by assessing selective executive function only and even conducted primarily from a major center of South India. In addition, it was found that male patients scored worse than female patients on copy organization as measured by Rey–Osterrieth metric. Whereas, OCD samples with more male patients performed significantly better on verbal and visuospatial working memory. Thus, further research is needed to corroborate visuospatial memory assessments revealing inconclusive patterns of impairments among patients with OCD that can prove to be an important avenue in better understanding and treatment of OCD. In view of this information, we aimed to study visuospatial memory in male patients with OCD.
| Materials and Methods|| |
A total of 30 patients, 15 diagnosed with OCD-contamination subtype and 15 normal healthy controls, were participated in the study. Diagnosis of OCD was made according to the International Classification of Diseases-10/DCR criteria that were confirmed by consultant psychiatrists of Central Institute of Psychiatry (CIP), Ranchi, India, where the study was conducted. Inclusion criteria required all participants to be male aged between 18 and 50 years, with minimum 8 years of formal education, and intelligence quotient (IQ) >80. Patients were excluded from participating in this study based on the exclusion criteria, i.e. any comorbid psychiatric illness except mild to moderate level of depression, history of major medical condition, obtained score < 7 and >31 on Yale–
Brown Obsessive-compulsive Scale (Y-BOCS), Hamilton Rating Scale for Depression-17 (HAM-D) score >17. Healthy controls were excluded from participation if they had psychiatry illness or neurological disorder, substance abuse, major medical condition, and score >3 on the General Health Questionnaire-12 (GHQ-12).
Y-BOCS, HAM-D 17, and Hamilton Rating Scale for Anxiety-14 (HAM-A) were administered to assess current psychopathology and severity of OCD, depression, and anxiety, respectively. In addition, healthy controls were rated on GHQ-12.
Assessment of visuospatial memory
The Extended Complex Figure Test (ECFT) is developed by Fastenau and Manning in 1992. The Rey–Osterrieth Figure Test (ROFT) has three domains to assess visuospatial memory, i.e., copy of a complex figure, immediate recall after 4 min, and delayed recall after 20 min. Unlike ROFT, ECFT included recognition and matching component with copy, immediate recall, delayed recall which allows the clinician to distinguish perceptual operations and encoding processes from constructional skills and retrieval process, respectively. Age-stratified norms are provided for children (ages 6–18) and adults (ages 19–85) with good reliability and validity.
Patients and healthy controls fulfilling the selection criteria were approached. After the informed consent, basic demographic information, and clinical characteristics, the evaluation of visuospatial memory was done. Psychiatric interviews were conducted by a trained psychiatrist, and visuospatial memory tests were administered by a trained clinical psychologist. On visuospatial memory task, participants were instructed to copy the ECFT figure with color pencils and subsequently after 3 min to draw what they remembered immediately (without intervening distraction), followed by 20-min delayed recall (other tests or interview were administered during this delay). After delayed recall, recognition and matching tasks were completed. Each interview session took approximately 40–50 min and cases were offered periodic breaks during testing. Controls for the study were unrelated attendants of patients, consenting staff members, employees of institute, and individuals from the community.
The data were analyzed using SPSS version 12.0 (SPSS, Chicago, IL, USA). Variables were first examined for normality using Shapiro–Wilk test. Comparison of demographic characteristics and visuospatial domains between clinical and control cases was done using independent sample t-test or Chi-square and Fisher's exact statistics as appropriate. In addition, Pearson bivariate correlation was used to identify correlations among the subdomains of Y-BOCS, HAM-A, HAM-D, and ECFT. Statistical significance was set at P< 0.05 and all tests were two-tailed.
Ethical approval for the study was obtained from the Ethics Committee of CIP and written informed consent was taken from all patients before participation.
| Results|| |
[Table 1], depicting demographic profile of sample, shows that both groups were homogeneous regarding marital status (P = 0.27), occupation (P = 0.56), religion (P = 0.31), socioeconomic status (P = 1.0), and residence (P = 0.33), and the two groups were well matched for age (t = −1.09; P= 0.29), education (t = −1.94; P= 0.062), and verbal IQ (t = −1.34; P= 0.019).
|Table 1: Demographic characteristics of patients with obsessive-compulsive disorder and healthy controls|
Click here to view
[Table 2] shows the clinical profile of OCD patients. We can see that the mean age of onset of OCD in the patient group was 21.6 (standard deviation [SD] =7.47) years, and mean duration of illness was 5.8 (SD = 5.03) years. The mean score of Y-BOCS (23.20 ± 6.79) showed a significant presence of OCD with a higher mean score of obsession (12.40 ± 3.87) as compared to compulsion (10.80 ± 3.6). HAM-D score (8.9 ± 3.04) indicates the presence of minor depression. None of our patients had a high score HAM-A (10.67 ± 4.56) indicating the absence of anxiety among patients.
|Table 2: Clinical profile of patients with obsessive-compulsive disorder group (n=15)|
Click here to view
Significant between-group difference on ECFT was found as assessment of visuospatial memory [Table 3]. Our patients performed significantly worse than the controls in all 5 conditions of the test, for example, they copied the complex figure less accurately and at incorrect place (t = −4.457; P < 0.001), they reproduced it less accurately in the immediate recall (t = −5.20; P< 0.001), delayed recall (t = −5.18; P < 0.001), they recognized and matched incorrect answer on recognition task (t = −6.49; P< 0.001) and matching task (= 5.35; P < 0.001).
|Table 3: Group comparison between obsessive-compulsive disorder patients and control groups on subdomains of the Extended Complex Figure Test|
Click here to view
In the OCD group, the Y-BOCS, HAM-A, and HAM-D did not correlate with any subdomain of visuospatial memory except a significant negative correlation between the immediate recall and HAM-D (r = −0.562, P< 0.05) [Table 4].
|Table 4: Pearson correlation coefficient among the clinical scales and subdomain of the Extended Complex Figure Test|
Click here to view
| Discussion|| |
The findings from our study reveal that patients with OCD performed worse than healthy controls on all the subdomains of ECFT, a measure of visuospatial memory. In other words, OCD patient copied and recalled the complex figure less accurately than the controls and took more time to copy and recall the figure that indicates poor performance on visual-spatial constructive abilities (copy a complex figure), visual memory (immediate recall), ability to retain visual-spatial material (delayed recall), adequacy of visual-spatial encoding processes (recognition), and visual-perceptual function (matching). Thus, the primary difficulty appeared to involve the ability to encode information from the copy condition. In addition, these impairments took place after controlled effects of age, education, intelligence, sociodemographic profile, and depression severity.
Our finding has an agreement with the majority of studies that concluded impaired visuospatial memory in patients with OCD.,,,,,,,, One study reported impairment in visuospatial analysis and synthesis, immediate visual recall, and visual discrimination in OCD patient. Whereas other studies found that OCD patients show a specific pattern of spatial memory dysfunction that might occur with the limited verbal mediation of stimuli., Purcell et al. compared thirty OCD participants, thirty patients with panic disorder, twenty unipolar depressive patients, and thirty healthy controls on a computerized neurocognitive battery. They concluded that on one hand, OCD patients had most pronounced visuospatial memory deficits and, on the other hand, they were similar to other psychiatric patients on a measure of nonverbal memory.
Recently, a study conducted by Tükel et al. suggested that OCD patients performed significantly worse than the controls on the Benton's Line Orientation and the Wechsler Adult Intelligence Scale-R Block Design subtest (WAIS-R-BD), indicated deficits in visuoperceptual and visuoconstructional tasks. Vandborg et al. have also documented group differences on the three conditions of the Rey Complex Figure Test (RCFT-copy, immediate recall, and delayed recall), a measure of visuospatial memory and organizational skills. In addition, effect sizes on between-group differences on the RCFT reported as moderate. A meta-analysis showed a small effect size for the copy component of the RCFT (d = −0.24) and for the visuospatial domain (d = −0.35) as well.
Few longitudinal studies have also confirmed the persistent nature of visuospatial or nonverbal memory dysfunctions in OCD patients.,, It persists even after treatment. A 1-year naturalistic study has been done by Roh et al. Authors assessed cognitive dysfunction in 21 patients with OCD after the start of medications. Assessment of cognitive function was carried out on three separate occasions, i.e., baseline, after 4 months, and after 1 year. Findings suggested that significant visuospatial or nonverbal memory impairments persisted in OCD patients despite clinical improvement at the 1-year follow-up assessment. In addition, at the time of 1-year assessment, they did not found an association between impairment in the accuracy of immediate and delayed recall with OCD symptoms. With respect to subclinical OCD and OCD spectrum disorder, these patients also displayed dysfunction in visual memory and of manipulating visuospatial information.
In contrast, some of the concurring studies disagreed with the visuospatial memory impairment in OCD per se. They argued that visuospatial memory dysfunction in OCD originates from organizational (executive) difficulties. Because of failure to use efficient executive strategies (organizational strategies) during encoding of the figure at the initial phase, i.e., copy the RCFT figure, OCD patients demonstrated reduced immediate and delayed recall.,,, Savage et al. proposed that dysfunction in visuospatial memory was mediated by impaired organizational strategies in OCD patients, i.e., secondary to impaired executive strategies during learning. Shin et al. have examined the frontal activity (measured as electroencephalogram alpha power), correlates with visuospatial functions (as measured by RCFT) in OCD. They found a correlation between greater left frontal activation (decreased alpha power) with a poorer RCFT copy score and greater right frontal activation with a better copy score. This finding supports the notion that visuospatial dysfunction in OCD is not in the visuospatial memory per se, however, mediated by executive function deficit. In his study, Moritz et al. have explored the specific elementary and complex visuospatial and nonverbal memory impairments in patients with OCD (n = 71), psychiatric control (n = 33), and healthy participants (n = 30) at two time-points (prior and subsequent to psychiatric treatment) to know the trait or state characteristics of dysfunction. In results, they did not find impaired visuospatial component in OCD patients except visuoconstruction impairment as measured by visuospatial transformation and block design performance.
On correlation analysis, it was found that the lower score on immediate recall task had a significant and negative correlation with the HAM-D score. This indicates that the severity of depression is associated with reduced immediate recall. Patients with elevated HDRS scores displayed performance deficits relative to OCD patients with low HDRS and controls.
Our study findings summarized that the patients with OCD might suffer from impaired visuospatial memory and organizational skills in their everyday life that worsen OCD symptoms. Neuropsychological model also explained that impaired executive function and memory in OCD exacerbate the illness. With the help of cognitive assessments, clinician can formulate direct cognitive rehabilitation for the deficit areas that can improve visuospatial memory functions and reduce OCD symptoms as well.
Furthermore, the findings of the study should be contextualized in terms of the strengths and limitations. The strength of the study includes assessing visuospatial memory by an extended form of RCFT. Some of the important limitations of our study include a small sample size with only male representation and a single measure of visuospatial memory. Furthermore, our patients were on psychotropic medication which could affect the cognition of patients. Future research needs to adapt more sophisticated neuropsychological probes that can better define elementary visuospatial deficits or the involvement of organizational strategies in it.
| Conclusion|| |
To summarize the current findings, OCD patients learned significantly less information during the figure copy and found significantly impaired visuospatial functioning. Hence, it can be concluded that assessment of the various deficit areas of visuospatial memory in OCD and its incorporation into the management plan are an emerging area to be studied.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (DSM-5®). Arlington: American Psychiatric Publishing; 2013.
Okasha A. Diagnosis of obsessive–compulsive disorder: A review. Obsessive–Compulsive Disorder. England: John Wiley and Sons, Ltd.; 2003. p. 1-41.
Ruscio AM, Stein DJ, Chiu WT, Kessler RC. The epidemiology of obsessive-compulsive disorder in the National Comorbidity Survey Replication. Mol Psychiatry 2010;15:53-63.
Friedlander L, Desrocher M. Neuroimaging studies of obsessive-compulsive disorder in adults and children. Clin Psychol Rev 2006;26:32-49.
Saxena S, Rauch SL. Functional neuroimaging and the neuroanatomy of obsessive-compulsive disorder. Psychiatr Clin North Am 2000;23:563-86.
Westenberg HG, Fineberg NA, Denys D. Neurobiology of obsessive-compulsive disorder: Serotonin and beyond. CNS Spectr 2007;12 Suppl 3:14-27.
Boone KB, Ananth J, Philpott L, Kaur A, Djenderedjian A. Neuropsychological characteristics of nondepressed adults with obsessive-compulsive disorder. Cogn Behav Neurol 1991;4:96-109.
Cha KR, Koo MS, Kim CH, Kim JW, Oh WJ, Suh HS, et al.
Nonverbal memory dysfunction in obsessive-compulsive disorder patients with checking compulsions. Depress Anxiety 2008;25:E115-20.
Christensen KJ, Kim SW, Dysken MW, Hoover KM. Neuropsychological performance in obsessive-compulsive disorder. Biol Psychiatry 1992;31:4-18.
Deckersbach T, Savage CR, Reilly-Harrington N, Clark L, Sachs G, Rauch SL. Episodic memory impairment in bipolar disorder and obsessive-compulsive disorder: The role of memory strategies. Bipolar Disord 2004;6:233-44.
Dirson S, Bouvard M, Cottraux J, Martin R. Visual memory impairment in patients with obsessive-compulsive disorder: A controlled study. Psychother Psychosom 1995;63:22-31.
Hartl TL, Frost RO, Allen GJ, Deckersbach T, Steketee G, Duffany SR, et al.
Actual and perceived memory deficits in individuals with compulsive hoarding. Depress Anxiety 2004;20:59-69.
Savage CR, Keuthen NJ, Jenike MA, Brown HD, Baer L, Kendrick AD, et al.
Recall and recognition memory in obsessive-compulsive disorder. J Neuropsychiatry Clin Neurosci 1996;8:99-103.
Zielinski CM, Taylor MA, Juzwin KR. Neuropsychological deficits in obsessive-compulsive disorder. Cogn Behav Neurol 1991;4:110-26.
Aronowitz BR, Hollander E, DeCaria C, Cohen L, Saoud JB, Stein D, et al
. Neuropsychology of obsessive compulsive disorder: Preliminary findings. Cogn Behav Neurol 1994;7:81-6.
Cohen LJ, Hollander E, DeCaria CM, Stein DJ, Simeon D, Liebowitz MR, et al.
Specificity of neuropsychological impairment in obsessive-compulsive disorder: A comparison with social phobic and normal control subjects. J Neuropsychiatry Clin Neurosci 1996;8:82-5.
Hollander E, Cohen L, Richards M, Mullen L, DeCaria C, Stern Y. A pilot study of the neuropsychology of obsessive-compulsive disorder and Parkinson's disease: Basal ganglia disorders. J Neuropsychiatry Clin Neurosci 1993;5:104-7.
Mataix-Cols D, Alonso P, Hernández R, Deckersbach T, Savage CR, Manuel Menchón J, et al.
Relation of neurological soft signs to nonverbal memory performance in obsessive-compulsive disorder. J Clin Exp Neuropsychol 2003;25:842-51.
Savage CR, Baer L, Keuthen NJ, Brown HD, Rauch SL, Jenike MA. Organizational strategies mediate nonverbal memory impairment in obsessive-compulsive disorder. Biol Psychiatry 1999;45:905-16.
Savage CR, Deckersbach T, Wilhelm S, Rauch SL, Baer L, Reid T, et al.
Strategic processing and episodic memory impairment in obsessive compulsive disorder. Neuropsychology 2000;14:141-51.
Zitterl W, Urban C, Linzmayer L, Aigner M, Demal U, Semler B, et al.
Memory deficits in patients with DSM-IV obsessive-compulsive disorder. Psychopathology 2001;34:113-7.
Nelson E, Early TS, Haller JW. Visual attention in obsessive-compulsive disorder. Psychiatry Res 1993;49:183-96.
Abramovitch A, Abramowitz JS, Mittelman A. The neuropsychology of adult obsessive-compulsive disorder: A meta-analysis. Clin Psychol Rev 2013;33:1163-71.
Abramovitch A, Dar R, Schweiger A, Hermesh H. Neuropsychological impairments and their association with obsessive-compulsive symptom severity in obsessive-compulsive disorder. Arch Clin Neuropsychol 2011;26:364-76.
Abbruzzese M, Ferri S, Scarone S. Wisconsin Card Sorting Test performance in obsessive-compulsive disorder: No evidence for involvement of dorsolateral prefrontal cortex. Psychiatry Res 1995;58:37-43.
Cavedini P, Zorzi C, Piccinni M, Cavallini MC, Bellodi L. Executive dysfunctions in obsessive-compulsive patients and unaffected relatives: Searching for a new intermediate phenotype. Biol Psychiatry 2010;67:1178-84.
Deckersbach T, Otto MW, Savage CR, Baer L, Jenike MA. The relationship between semantic organization and memory in obsessive-compulsive disorder. Psychother Psychosom 2000;69:101-7.
Menzies L, Achard S, Chamberlain SR, Fineberg N, Chen CH, del Campo N, et al.
Neurocognitive endophenotypes of obsessive-compulsive disorder. Brain 2007;130:3223-36.
Moritz S, Kloss M, Jahn H, Schick M, Hand I. Impact of comorbid depressive symptoms on nonverbal memory and visuospatial performance in obsessive-compulsive disorder. Cogn Neuropsychiatry 2003;8:261-72.
Okasha A, Rafaat M, Mahallawy N, El Nahas G, El Dawla AS, Sayed M, et al.
Cognitive dysfunction in obsessive-compulsive disorder. Acta Psychiatr Scand 2000;101:281-5.
Penadés R, Catalán R, Rubia K, Andrés S, Salamero M, Gastó C. Impaired response inhibition in obsessive compulsive disorder. Eur Psychiatry 2007;22:404-10.
Purcell R, Maruff P, Kyrios M, Pantelis C. Neuropsychological deficits in obsessive-compulsive disorder: A comparison with unipolar depression, panic disorder, and normal controls. Arch Gen Psychiatry 1998;55:415-23.
van den Heuvel OA, Veltman DJ, Groenewegen HJ, Witter MP, Merkelbach J, Cath DC, et al.
Disorder-specific neuroanatomical correlates of attentional bias in obsessive-compulsive disorder, panic disorder, and hypochondriasis. Arch Gen Psychiatry 2005;62:922-33.
Härting C, Markowitsch HJ. Neuropsychological findings in obsessive-compulsive disorder. Fortschr Neurol Psychiatr 1997;65:509-15.
Kuelz AK, Hohagen F, Voderholzer U. Neuropsychological performance in obsessive-compulsive disorder: A critical review. Biol Psychol 2004;65:185-236.
Tallis F. The neuropsychology of obsessive-compulsive disorder: A review and consideration of clinical implications. Br J Clin Psychol 1997;36:3-20.
Lacerda AL, Dalgalarrondo P, Caetano D, Haas GL, Camargo EE, Keshavan MS. Neuropsychological performance and regional cerebral blood flow in obsessive-compulsive disorder. Prog Neuropsychopharmacol Biol Psychiatry 2003;27:657-65.
Saxena S, Brody AL, Schwartz JM, Baxter LR. Neuroimaging and frontal-subcortical circuitry in obsessive-compulsive disorder. Br J Psychiatry Suppl 1998;35:26-37.
Kerkhoff G. Multiple perceptual distortions and their modulation in leftsided visual neglect. Neuropsychologia 2000;38:1073-86.
Moritz S, Kloss M, Jacobsen D, Kellner M, Andresen B, Fricke S, et al.
Extent, profile and specificity of visuospatial impairment in obsessive-compulsive disorder (OCD). J Clin Exp Neuropsychol 2005;27:795-814.
Kohli A, Rana DK, Gupta N, Kulhara P. Neuropsychological assessment in obsessive-compulsive disorder. Indian J Psychol Med 2015;37:205-11.
] [Full text]
Krishna R, Udupa S, George CM, Kumar KJ, Viswanath B, Kandavel T, et al.
Neuropsychological performance in OCD: A study in medication-naîve patients. Prog Neuropsychopharmacol Biol Psychiatry 2011;35:1969-76.
Rao NP, Reddy YC, Kumar KJ, Kandavel T, Chandrashekar CR. Are neuropsychological deficits trait markers in OCD? Prog Neuropsychopharmacol Biol Psychiatry 2008;32:1574-9.
Roopesh BN, Mukundan CR, Pradan N, Reddy YC. Stability of neuropsychological deficits with respect to treatment outcome in OCD. Indian J Clin Psychol 2005;32:172.
Sharma S, Vaish S, Trivedi JK, Dalal PK. Neurocognitive deficits in obsessive compulsive disorder: A state or trait phenomenon? J Health Hum Behav 2014;19:78.
Trivedi JK, Dhyani M, Goel D, Sharma S, Singh AP, Sinha PK, et al.
Neurocognitive dysfunction in patients with obsessive compulsive disorder. Afr J Psychiatry (Johannesbg) 2008;11:204-9.
Segalàs C, Alonso P, Labad J, Real E, Pertusa A, Jaurrieta N, et al.
A case-control study of sex differences in strategic processing and episodic memory in obsessive-compulsive disorder. Compr Psychiatry 2010;51:303-11.
Goodman WK, Price LH, Rasmussen SA, Mazure C, Fleischmann RL, Hill CL, et al.
The Yale-Brown Obsessive Compulsive Scale. I. Development, use, and reliability. Arch Gen Psychiatry 1989;46:1006-11.
Hamilton M. The assessment of anxiety states by rating. Br J Med Psychol 1959;32:50-5.
Hamilton M. A rating scale for depression. J Neurol Neurosurg Psychiatry 1960;23:56-62.
Golderberg D, Williams P. A User's Guide to the General Health Questionnaire. Windsor, UK: NFER-Nelson; 1988.
Fastenau PS, Manning AA. Development of a recognition task for the Extended Complex Figure Test. J Clin Exp Neuropsychol 1992;14:43.
Vandborg SK, Hartmann TB, Bennedsen BE, Pedersen AD, Thomsen PH. Memory and executive functions in patients with obsessive-compulsive disorder. Cogn Behav Neurol 2014;27:8-16.
Boldrini M, Del Pace L, Placidi GP, Keilp J, Ellis SP, Signori S, et al.
Selective cognitive deficits in obsessive-compulsive disorder compared to panic disorder with agoraphobia. Acta Psychiatr Scand 2005;111:150-8.
Kim MS, Park SJ, Shin MS, Kwon JS. Neuropsychological profile in patients with obsessive-compulsive disorder over a period of 4-month treatment. J Psychiatr Res 2002;36:257-65.
Penadés R, Catalán R, Andrés S, Salamero M, Gastó C. Executive function and nonverbal memory in obsessive-compulsive disorder. Psychiatry Res 2005;133:81-90.
Rampacher F, Lennertz L, Vogeley A, Schulze-Rauschenbach S, Kathmann N, Falkai P, et al.
Evidence for specific cognitive deficits in visual information processing in patients with OCD compared to patients with unipolar depression. Prog Neuropsychopharmacol Biol Psychiatry 2010;34:984-91.
Roh KS, Shin MS, Kim MS, Ha TH, Shin YW, Lee KJ, et al.
Persistent cognitive dysfunction in patients with obsessive-compulsive disorder: A naturalistic study. Psychiatry Clin Neurosci 2005;59:539-45.
Segalàs C, Alonso P, Labad J, Jaurrieta N, Real E, Jiménez S, et al.
Verbal and nonverbal memory processing in patients with obsessive-compulsive disorder: Its relationship to clinical variables. Neuropsychology 2008;22:262-72.
Purcell R, Maruff P, Kyrios M, Pantelis C. Cognitive deficits in obsessive-compulsive disorder on tests of frontal-striatal function. Biol Psychiatry 1998;43:348-57.
Tükel R, Gürvit H, Ertekin BA, Oflaz S, Ertekin E, Baran B, et al.
Neuropsychological function in obsessive-compulsive disorder. Compr Psychiatry 2012;53:167-75.
Bolton D, Raven P, Madronal-Luque R, Marks IM. Neurological and neuropsychological signs in obsessive compulsive disorder: Interaction with behavioural treatment. Behav Res Ther 2000;38:695-708.
Nielen MM, Den Boer JA. Neuropsychological performance of OCD patients before and after treatment with fluoxetine: Evidence for persistent cognitive deficits. Psychol Med 2003;33:917-25.
Shin MS, Park SJ, Kim MS, Lee YH, Ha TH, Kwon JS. Deficits of organizational strategy and visual memory in obsessive-compulsive disorder. Neuropsychology 2004;18:665-72.
Greisberg S, McKay D. Neuropsychology of obsessive-compulsive disorder: A review and treatment implications. Clin Psychol Rev 2003;23:95-117.
[Table 1], [Table 2], [Table 3], [Table 4]