Title:Mnemonic Discrimination in Obsessive Compulsive Disorder Patients: A Case-Control Study
Volume: 17
Issue: 3
Author(s): Giulia Anna Aldi , Giovanni Mansueto , Umberto Albert, Claudia Cumerlato Melter , Giuseppe Maina and Fiammetta Cosci *
Affiliation:
- Department of Health Sciences, University of Florence, Florence,Italy
Keywords:
Mnemonic discrimination, pattern separation, overgeneralization, obsessive-compulsive disorder, obsessions, compulsions.
Abstract: Background: Fear generalization is an adaptive mechanism which enables
an individual to appropriately respond to novel stimuli based on overlapping
features with a learned threat stimulus. When it is maladaptive, it is named
overgeneralization. Overgeneralization was observed in psychiatric disorders, including
Obsessive-Compulsive Disorder (OCD). Overgeneralization seems to be
related to mnemonic discrimination, a fundamental component of memory which
encodes a given event as distinct from highly similar events. Mnemonic discrimination
is thought to rely on Pattern Separation (PS), which plays a critical role in
discriminating safe stimuli similar to threatening ones. PS performance showed
to be impaired in patients with some psychiatric disorders but has never been
studied in OCD.
Objective: Mnemonic discrimination for context, used as a proxy of pattern separation,
was measured in patients with OCD to verify whether it is related to overgeneralization.
Methods: Thirty patients with OCD and 30 non-psychiatric controls were enrolled
(matched for sex, age). The Mnemonic Similarity Task-Object and the
Mnemonic Similarity Task-Contest were administered to assess PS performance.
Results: When patients with OCD and controls were compared, statistically significant
differences were not found for mnemonic performances and pattern separation.
Based on multivariate regression analysis, the group of patients with OCD
was more likely to report lower mnemonic discrimination for context (OR =
0.67, 95% CI = 0.48-0.93) than the control group.
Conclusion: Mnemonic discrimination for context was specifically referred to as
new lures misidentified as similar. It is hypothesized that pattern separation performances
might discriminate patients with OCD from non-psychiatric subjects.
