The specificity of schizophrenic thought disorder

Area of Science:

• Psychology
• Clinical Psychology
• Psychopathology

Background:

• Previous repertory grid studies reported differences in reliability and social agreement between thought-disordered schizophrenics and normal individuals when construing people versus objects.
• The validity of these findings is questionable due to confounding variables, including those identified in subsequent research.
• Prior research also suggested that pure consistency, rather than construct intensity, effectively discriminates between thought-disordered schizophrenics and other groups in repertory grid tests.

Purpose of the Study:

• To investigate the effects of confounding variables on repertory grid performance in thought-disordered schizophrenics.
• To replicate or refute findings regarding pure consistency versus construct intensity as discriminators in repertory grid tests.
• To clarify the diagnostic utility of repertory grid techniques for thought-disordered schizophrenia.

Main Methods:

• Administered six repertory grids to 10 thought-disordered schizophrenics, 10 non-thought-disordered schizophrenics, and 10 normal controls.
• Grids involved rating familiar and unfamiliar people and objects on psychological and physical constructs.
• Analyzed data for grids x diagnoses interactions on pure consistency and construct intensity, controlling for pure consistency.

Main Results:

• No significant grids x diagnoses interaction was found for pure consistency.
• A significant grids x diagnoses interaction was observed for construct intensity, even after partialling out pure consistency.
• The findings confirmed previous research indicating pure consistency as the primary discriminator, while the effect of intensity was found to be weak and inconsistent.

Conclusions:

• Pure consistency, not the intensity of construct relationships, is the effective discriminator between thought-disordered schizophrenics and other groups in repertory grid tests.
• The observed interaction effect on intensity is weak, inconsistent across studies, and anomalous in the current experiment.
• Repertory grid methodology requires careful control of confounding variables to ensure valid diagnostic differentiation in schizophrenia.