Deviations in early hippocampus development contribute to visual hallucinations in schizophrenia

Area of Science:

• Neuroscience
• Psychiatry
• Developmental biology

Background:

• Schizophrenia often involves visual hallucinations (VHs), which may relate to brain development differences.
• Hippocampal impairments are linked to hallucinations in schizophrenia, particularly VHs.
• The neurodevelopmental origins of hippocampal issues in VHs remain understudied.

Purpose of the Study:

• Investigate the neurodevelopmental origin of hippocampal impairments in visual hallucinations (VHs) in schizophrenia.
• Compare incomplete hippocampal inversion (IHI) patterns in healthy controls, schizophrenia patients with pure auditory hallucinations (AHs), and those with audio-visual hallucinations (A+VH).

Main Methods:

• Compared IHI patterns in three groups: healthy volunteers, pure AHs patients, and A+VH patients.
• Utilized neuroimaging to assess hippocampal morphology and inversion patterns.
• Focused on incomplete hippocampal inversion (IHI) as a marker of early atypical hippocampal development.

Main Results:

• Visual hallucinations (VHs) are associated with a distinct IHI pattern.
• Schizophrenia patients with A+VH exhibited flatter left hippocampi compared to pure AHs patients and healthy controls.
• This suggests a greater neurodevelopmental influence in A+VH patients.

Conclusions:

• Findings confirm a link between greater clinical impairment in A+VH patients and neurodevelopmental factors.
• Results provide insights into the sensitive developmental periods for A+VH-related incomplete hippocampal inversion (IHI).
• Highlights the importance of studying neurodevelopmental trajectories in schizophrenia subtypes.