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“Need to Know” or the Strong Urge to Find Names of Unique Entities in Acquired Obsessive-Compulsive Disorder

Edelkraut, Lisa MS*,†; Berthier, Marcelo L. MD, PhD*; Green-Heredia, Cristina PhD; López-González, Francisco J. MS§,∥; Roé-Vellvé, Núria PhD§,¶; Torres-Prioris, María José MS*,†; Tubío, Javier PhD*,#; López-Barroso, Diana PhD*,†

Cognitive and Behavioral Neurology: June 2019 - Volume 32 - Issue 2 - p 124–133
doi: 10.1097/WNN.0000000000000192
Case Reports

The two forms of obsessive-compulsive disorder (OCD), idiopathic and acquired, have been linked to abnormalities in the fronto-striato-thalamo-cortical circuitry, involving the orbitofrontal cortex, anterior cingulate cortex, thalamus, and striatum. Accumulating evidence indicates that damage to other brain regions (ie, temporal lobes) is also implicated in the pathogenesis of both types of OCD. In addition, some discrete OCD symptoms have received less attention because of their presumed low occurrence and difficultly of categorization. Among these, one intriguing and potentially severe type of obsessive thinking is the so-called “need to know” (NtK), which is a strong urge to access certain information, particularly proper names. In some patients, this monosymptomatic presentation may constitute the major feature of OCD. Here we report the cases of two patients who developed NtK obsessions with tenacious time-consuming, answer-seeking compulsions as the only or more disabling symptomatology in association with malignant tumors involving the right temporal lobe and connected fronto-subcortical circuits.

*Cognitive Neurology and Aphasia Unit, Institute of Biomedical Research in Malaga

Department of Psychobiology and Methodology of Behavioural Sciences, Faculty of Psychology

§Molecular Imaging Unit, Medical-Sanitary Research Centre General Foundation, University of Malaga, Malaga, Spain

Service of Neuropsychology, Hospital Quirón, Malaga, Spain

Department of Psychiatry, Radiology and Public Health, Molecular Imaging and Medical Physics Group, University of Compostela, Galicia, Spain

Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine, Barcelona, Spain

#Faculty of Education, International University of La Rioja, Logroño, Spain

Supported in part by PhD scholarships from the Spanish Ministry of Education, Culture and Sport under the Training University Lecturers Program (Formación de Profesorado Universitario [FPU]) to L.E. (FPU17/04136), F.J.L.-G. (FPU17/04470), and M.J.T.-P. (FPU14/04021); and by a postdoctoral grant from the University of Malaga to D.L.-B.

The authors declare no conflicts of interest.

Correspondence: Marcelo L. Berthier, MD, PhD, Unidad de Neurología Cognitiva y Afasia, Centro de Investigaciones Médico-Sanitarias, Universidad de Málaga, Marqués de Beccaria 3, 29010, Málaga, España (email:

Received May 22, 2018

Accepted February 1, 2019

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