title: Hippocampal volume in subjects at clinical high-risk for psychosis: A systematic review and meta-analysis.
abstract: Several magnetic resonance imaging studies have reported reductions in hippocampal volume in patients with psychosis. It is unclear whether structural abnormalities predate illness onset. We conducted a detailed, systematic literature search for studies reporting hippocampal volume in subjects with clinical high-risk, compared to healthy controls. The overall sample size comprised 1429 subjects. Meta-analysis revealed no difference for left, but a small, albeit significant, difference for right hippocampal volume, such that clinical high-risk patients had slightly smaller hippocampal volume than healthy controls (g=0.24, p=0.0418). Meta-regression indicated a moderating effect of manual tracing approach, due to one outlying site. The small difference on the right side did not remain significant (g=0.14, 95%CI=[-0.03-0.32], p=0.11) after removal of this outlier. This meta-analysis suggests that there is no reduction in hippocampal volume before transition to psychosis and hippocampal volume cannot be used as a biomarker in clinical high-risk individuals.
authors: Psychiatric University Clinics (UPK) Basel, Basel, Switzerland. Electronic address: anna.walter@unibas.ch.
authors: Anna
authors: A
authors: Walter
authors: Clinical Pharmacology and Toxicology, University Hospital Basel, Basel, Switzerland.
authors: Claudia
authors: C
authors: Suenderhauf
authors: Psychiatric University Clinics (UPK) Basel, Basel, Switzerland.
authors: Fabienne
authors: F
authors: Harrisberger
authors: Psychiatric University Clinics (UPK) Basel, Basel, Switzerland.
authors: Claudia
authors: C
authors: Lenz
authors: Psychiatric University Clinics (UPK) Basel, Basel, Switzerland.
authors: Renata
authors: R
authors: Smieskova
authors: Department of Psychology, Yale University, New Haven, CT, United States.
authors: Yoonho
authors: Y
authors: Chung
authors: Department of Psychology, Yale University, New Haven, CT, United States.
authors: Tyrone D
authors: TD
authors: Cannon
authors: Departments of Psychiatry, Psychology and Brain Research Institute, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, United States.
authors: Carrie E
authors: CE
authors: Bearden
authors: Center for Psychosis Treatment, Psychiatry Clinics Solothurn, Solothurn, Switzerland.
authors: Charlotte
authors: C
authors: Rapp
authors: Medical Image Analysis Center, University of Basel, Basel, Switzerland.
authors: Kerstin
authors: K
authors: Bendfeldt
authors: Psychiatric University Clinics (UPK) Basel, Basel, Switzerland.
authors: Stefan
authors: S
authors: Borgwardt
authors: Psychiatric University Clinics (UPK) Basel, Basel, Switzerland.
authors: Tobias
authors: T
authors: Vogel
mesh_terms: D007839:Functional Laterality; D006624:Hippocampus; D006801:Humans; D008279:Magnetic Resonance Imaging; D011618:Psychotic Disorders; D012559:Schizophrenia
keywords: At-risk mental state; Biomarker; Clinical high-risk; Early detection; Hippocampus; Magnetic resonance imaging; Psychosis; Ultra high-risk