A literature review suggested age and cognitive problems to be related to an increased prevalence of small areas of signal variation within the hippocampus observed on MRI, described as hippocampal sulcal cavities (HSCs; (Maller et al., 2011)). The current study aimed to describe the prevalence of HSCs in patients with treatment-resistant depression (TRD) and healthy controls over a large age-range. Methods: 115 TRD patients and 86 controls underwent MRI brain scanning. Right and left HSCs were rated separately for prevalence and length. Results: HSCs were observed in 73.04 of those with TRD, statistically more prevalent (p=0.001) than amongst controls (51.16 ). These findings are consistent with our review (66 prevalence in memory disorders and 47 in healthy controls). Furthermore, HSC presence and length was associated with aging. Limitations: The study was cross-sectional so its implications for aging are tentative. A larger sample scanned longitudinally will allow for more sophisticated statistical methods by which to investigate the relationship between HSCs, aging, and TRD. Conclusions: Although their clinical significance remains uncertain, the results of the current study suggest that HSCs are related with age and those with TRD have more aged brains than their peers. Crown Copyright ? 2013 Published by Elsevier B.V. All rights reserved.