Schizophrenia and the neurodevelopmental continuum:evidence from genomics

Area of Science:

• Neuroscience
• Psychiatry
• Genetics

Background:

• The neurodevelopmental hypothesis posits early brain development disturbances cause schizophrenia.
• Schizophrenia is currently viewed as distinct from childhood neurodevelopmental disorders like autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and intellectual disability (ID).

Purpose of the Study:

• To test the neurodevelopmental continuum model and gradient hypothesis for severe mental illnesses.
• To investigate shared genetic risk and pathogenic mechanisms between schizophrenia and early-onset neurodevelopmental disorders.

Main Methods:

• Review of recent large-scale genomic studies identifying specific DNA risk changes.
• Analysis of findings in relation to the neurodevelopmental continuum and gradient hypotheses.

Main Results:

• Genomic data support schizophrenia originating from brain development disturbances.
• Schizophrenia shares genetic risks and pathogenic mechanisms with ID, ASD, and ADHD.
• Evidence suggests these disorders lie on a severity gradient, differing quantitatively and qualitatively.

Conclusions:

• Schizophrenia and early-onset neurodevelopmental disorders may represent a continuum rather than discrete entities.
• Findings support a gradient of neurodevelopmental impairment across these conditions.
• Implications for nosology, clinical practice, and research into severe mental illnesses.