Hippocampus and depression. Data from the Danish PET/depression project with 8 years follow-up

Abstract

In the past decades, several lines of research have pointed towards involvement of the hippocampus in the pathogenesis of major depression.

In “The Danish PET/Depression Projectâ€, which we carried out from 1995 to 1998, we found abnormal blood flow to the hippocampus using positron emission tomography (PET) during rest (Videbech et al.2001b;Videbech et al.2002). The patients were also studied using MRI (Videbech et al.2001a).

Furthermore, a meta-analysis of MR studies of patients with major depression has shown atrophy of this structure especially with increasing number of episodes (Videbech and Ravnkilde2004). This has been confirmed by other researchers.

It is a widely recognized hypothesis that severe depression could be toxic for the hippocampus. Hence, the more intense the history of depression, the smaller the hippocampus (Nestler et al.2002;Gorwood et al.2008;Videbech2005).

On this background one would expect that our original sample of depressed patients, who had several episodes of depression during the eight years follow-up period, would show signs of hippocampal atrophy and dysfunction when examined with PET, MRI and neuropsychological testing.

Results from this follow-up study are presented.

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