Screening for schizophrenia in initial prodromal phase: Detecting the sub-threshold psychosis

Area of Science:

• Psychiatry
• Mental Health Research
• Genetic Epidemiology

Background:

• Sub-threshold psychosis affects individuals at genetic risk for schizophrenia.
• Early detection of psychosis is crucial for intervention.
• Screening tools need validation for at-risk populations.

Purpose of the Study:

• To evaluate screening tools for detecting sub-threshold psychosis in individuals with genetic risk.
• To compare screening tool efficacy between at-risk relatives and the general public.

Main Methods:

• A two-stage study involving relatives of schizophrenia patients and general individuals.
• Initial screening using the Screening Questionnaire (SQ) and General Health Questionnaires (GHQ-12).
• Second-stage reassessment with the Comprehensive Assessment of At-Risk Mental State (CAARMS) for positive screens.

Main Results:

• 190 (29%) of 660 individuals screened positive initially.
• Higher progression to the second stage in the general public (63%) vs. at-risk relatives (37.4%).
• Approximately 4% were positive on final assessment; 69% were sub-threshold ultra-high risk (UHR).
• Higher detection rates when both GHQ and SQ were positive (26.4%).
• Subjects at genetic risk showed higher prevalence (62%) of sub-threshold psychosis.

Conclusions:

• Sub-threshold psychosis is more prevalent in individuals with a genetic predisposition.
• Mandatory clinical assessment is necessary due to high false positive rates from self-report questionnaires.
• The SQ shows poor validation, and the GHQ is unsuitable for early psychosis screening.