Elsevier

NeuroImage: Clinical

Volume 12, February 2016, Pages 949-955
NeuroImage: Clinical

Hippocampal volume predicts antidepressant efficacy in depressed patients without incomplete hippocampal inversion

https://doi.org/10.1016/j.nicl.2016.04.009Get rights and content
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Highlights

  • Incomplete hippocampal inversion (IHI) is not significantly more frequent in MDD than in controls.

  • IHI is not significantly associated with MDD clinical characteristics.

  • Hippocampal volume predicts antidepressant efficacy in MDD patients without IHI.

  • Hippocampal volume does not predict antidepressant efficacy in patients with IHI.

Abstract

Background

Incomplete hippocampal inversion (IHI), also called malrotation, is a frequent atypical anatomical pattern of the hippocampus. Because of the crucial implication of the hippocampus in Major Depressive Disorder (MDD) and the neurodevelopmental hypothesis of MDD, we aimed to assess the prevalence of IHI in patients with MDD, the link of IHI with hippocampal volume (HV) and the impact of IHI on the predictive value of HV for response and remission after antidepressant treatment.

Methods

IHI (right and left, partial and total and IHI scores) and HV were assessed in 60 patients with a current Major Depressive Episode (MDE) in a context of MDD and 60 matched controls. Patients were prospectively assessed at baseline and after one, three and six months of antidepressant treatment for response and remission.

Results

The prevalence of IHI did not significantly differ between MDD patients (right = 23.3%; left = 38.3%) and controls (right = 16.7%; left = 33.3%). IHI was not significantly associated with MDD clinical characteristics. IHI alone did not predict response and remission after antidepressant treatment. However, an interaction between left HV and left IHI predicted six-month response (p = 0.04), HDRS score decrease (p = 0.02) and both three-month (p = 0.04) and six-month (p = 0.03) remission. A case-control design in 30 matched patients with or without left IHI confirmed that interaction. In patients without left IHI, left HV at baseline were smaller in six-month non-remitters as compared to remitters (2.2(± 0.43) cm3 vs 2.97(± 0.5) cm3 p = 0.02), and in six-month non-responders as compared to responders (2.18(± 0.42) cm3 vs 2.86(± 0.54) cm3, p = 0.03). In patients with left IHI, no association was found between left HV at baseline and antidepressant response and remission.

Conclusion

IHI is not more frequent in MDD patients than in controls, is not associated with HV, but is a confounder that decreases the predictive value of hippocampal volume to predict response or remission after antidepressant treatment. IHI should be systematically assessed in future research studies assessing hippocampal volume in MDD.

Abbreviations

HV
hippocampal volume
IHI
Incomplete Hippocampal Inversion
MDD
Major Depressive Disorder
MDE
Major Depressive Episode

Keywords

Major Depressive Disorder
Hippocampal volume
Incomplete Hippocampal Inversion
Antidepressant
Response
Remission

Cited by (0)

1

These 2 authors contributed equally to this work.