Hippocampal Volume Reduction in First-Episode and Chronic Schizophrenia

Abstract

Several magnetic resonance imaging studies have reported hippocampal volume reduction in patients with schizophrenia, but other studies have reported contrasting results. In this review and meta-analysis, the authors aim to clarify whether a reduction in hippocampal volume characterizes patients with schizophrenia by considering illness phase (chronic and first episode) and hippocampus side separately. They made a detailed literature search for studies reporting physical volumetric hippocampal measures of patients with schizophrenia and healthy control (HC) participants and found 44 studies that were eligible for meta-analysis. Individual meta-analyses were also performed on 13 studies of first-episode patients and on 22 studies of chronic patients. The authors also detected any different findings when only males or both males and females were considered. Finally, additional meta-analyses and analyses of variance investigated the role of the factors "illness phase" and "side" on hippocampal volume reduction. Overall, the patient group showed significant bilateral hippocampal volume reduction compared with HC. Interestingly, first-episode and chronic patients showed same-size hippocampal volume reduction. Moreover, the left hippocampus was smaller than the right hippocampus in patients and HC. This review and meta-analysis raises the question about whether hippocampal volume reduction in schizophrenia is of neurodevelopmental origin. Future studies should specifically investigate this issue.

Familial and environmental influences on brain volumes in twins with schizophrenia

“…Medial temporal lobe and hippocampal volume deficits are widely recognized in patients with schizophrenia. 43 Evidence from high-risk cohorts has linked this structure specifically to the onset of psychosis, 44 with evidence also of a link with illness progression. 43,45,46 Sibling and twin studies have detected volume deficits in unaffected relatives, 20 which suggests an interaction between genetic and familial environment.…”

“…43 Evidence from high-risk cohorts has linked this structure specifically to the onset of psychosis, 44 with evidence also of a link with illness progression. 43,45,46 Sibling and twin studies have detected volume deficits in unaffected relatives, 20 which suggests an interaction between genetic and familial environment. 22,47 It may be that the hippocampus is vulnerable to a variety of environmental factors, including obstetric complications 48 and stress, 49 varying according to the hormonal milieu 50 that is then linked to schizophrenia.…”

COMT, neuropsychological function and brain structure in schizophrenia: a systematic review and neurobiological interpretation

“…111 State independence: Hippocampus reductions seem to be state-independent and have been reported in patients at both first episode and chronic illness stages. 112 Cosegregation with illness within the family: Cosegregation is suggested by the presence of hippocampal volume reduction among relatives of patients with schizophrenia, 113 particularly in multiplex families. 114 Presence in unaffected relatives: Results from a metaanalysis indicate that amygdalar and hippocampal volume reductions are also present in relatives of patients with schizophrenia.…”

A schizophrenia-associated HLA locus affects thalamus volume and asymmetry

“…The hippocampus has well-studied roles in long-term and working memory, which are abilities that are often impaired in people with schizophrenia (Aleman et al, 1999;Libby et al, 2013). A reduction of hippocampal volume and/or alterations of hippocampal asymmetry have been found by independent studies and meta-analyses to associate with schizophrenia (Adriano et al, 2012;Gruber et al, 2008;Hasan et al, 2011;Haukvik et al, 2013;Jaaro-Peled et al, 2010;Shenton et al, 2010;Shepherd et al, 2012).…”