Insight differences between deficit and non-deficit schizophrenia: a systematic review and meta-analysis

Area of Science:

• Psychiatry
• Clinical Psychology
• Neuroscience

Background:

• Deficit schizophrenia (DS) is associated with lower insight compared to non-deficit schizophrenia (NDS).
• The precise relationship between DS and insight deficits remains unclear.
• This study systematically reviews and meta-analyzes insight differences between DS and NDS patients.

Purpose of the Study:

• To systematically review and meta-analyze studies comparing insight levels in deficit schizophrenia (DS) versus non-deficit schizophrenia (NDS).
• To understand the association between insight, negative symptoms, and cognitive function in DS.

Main Methods:

• A PRISMA-compliant systematic review and meta-analysis of studies from PubMed, Scopus, and Web of Science.
• Inclusion of studies examining insight differences between DS and NDS, using any validated insight measure.
• Narrative synthesis and random-effects meta-analysis (SMD) of outcome data, with risk of bias and certainty of evidence assessed (JBI, GRADE).

Main Results:

• Nine studies (N=895; n=239 DS) were included.
• Narrative synthesis indicated greater insight deficits in DS, linked to expressive negative symptoms and metacognitive impairments.
• Meta-analysis revealed significantly poorer insight in DS vs. NDS (SMD=0.99, p=0.009), with substantial heterogeneity (I²=82.1%).

Conclusions:

• Deficit schizophrenia patients demonstrate significantly poorer insight compared to NDS patients.
• Poorer insight in DS is associated with enduring negative symptoms and cognitive dysfunction, particularly in self-reflection.
• Interventions targeting these cognitive and metacognitive deficits may enhance insight and patient outcomes.