The hippocampus and executive functions in depression

• Published in: Industrial psychiatry journal Vol. 24; no. 1; pp. 18 - 22
• Main Authors: Khan, Shahbaz Ali, Ryali, Vssr, Bhat, Pookala Shivaram, Prakash, Jyoti, Srivastava, Kalpana, Khanam, Shagufta
• Format: Journal Article
• Language: English
• Published: India Medknow Publications and Media Pvt. Ltd 01.01.2015; Medknow Publications & Media Pvt. Ltd; Medknow Publications & Media Pvt Ltd; Wolters Kluwer Medknow Publications
• Subjects: Antidepressants; Atrophy; Brain; Depression; Depression (Mood disorder); Electroconvulsive therapy; executive deficits; Executive function; Executive function (Psychology); Health aspects; hippocampus; Hippocampus (Brain); Illnesses; Magnetic resonance imaging; Mental depression; Mental disorders; Neurosciences; NMR; Nuclear magnetic resonance; Original; Psychiatric research; Studies; Variance analysis; wisconsin card sorting test; India; Wisconsin; Depression; magnetic resonance imaging; hippocampus; wisconsin card sorting test; executive deficits
• ISSN: 0972-6748; 0976-2795
• DOI: 10.4103/0972-6748.160920

The relationship between depression, hippocampus (HC), and executive dysfunctions seems complex and has been the focus of research. Recent evidence indicates a possible role of HC in executive dysfunction seen in depression. No such studies on Indian population have been done. To look for changes in HC and executive functions in depression. A cross-sectional analytical controlled study. Sample size 50 (controls 50). Hippocampal volume and executive dysfunction was measured using structural magnetic resonance imaging (MRI) and Wisconsin Card Sorting Test (WCST), respectively. Findings on these two parameters were compared between depressives and healthy matched controls as well as between first episode (FE) and recurrent depressives and across the severity of depression (mild, moderate, and severe). Statistical Package for Social Sciences (SPSS) version 17 was used for analysis. Normally distributed continuous variables were analyzed with independent t-tests. Analysis of variance (ANOVA) was used for multiple comparisons. Categorical data were compared with χ(2) or Fisher's exact test. Clinical correlations were conducted using Pearson correlations. Depressed patients had a smaller left (Lt) hippocampal volume as well as poor performance on several measures of executive functions. Smaller hippocampal volume was found even in FE. Those who had a past burden of depressive illness had an even smaller hippocampal volume. No direct correlation was found between the HC volume and cognitive dysfunction. Depressive illness appears to be toxic to the HC. The relationship between HC and executive dysfunction in depression may be indirect through its functional connections.