Background: An accurate identification of individuals at ultra-high risk (UHR) based on psychometric tools to prospectively identify psychosis as early as possible is required for indicated preventive intervention. The diagnostic comparability of several psychometric tools, including the comprehensive assessment of at risk mental state (CAARMS), the structured interview for psychosis-risk syndrome (SIPS) and the bonn scale for the assessment of basic symptoms (BSABS), is unknown.
Aim: To address the psychometric comparability of CAARMS, SIPS and BSABS for subjects who are close relatives of patients with schizophrenia.
Methods: In total, 189 participants aged 18-58 years who were lineal relative by blood and collateral relatives by blood up to the third degree of kinship of patients with schizophrenia were interviewed in the period of May 2017 to January 2019. Relatives of the participants diagnosed schizophrenia were excluded. All the participants were assessed for a UHR state by three psychometric tools (CAARMS, SIPS and BSABS). The psychometric diagnosis results included at risk of psychosis (UHR+), not at risk of psychosis (UHR-) and psychosis. Demographic and clinical characteristics were also measured. The inter-rater agreement was assessed for evaluation of the coherence of the three scales. Transition rates for UHR+ subjects to psychosis within 2 years were also recorded.
Results: The overall agreement percentages were 93.12%, 92.06% and 93.65% of CAARMS and SIPS, SIPS and BSABS and CAARMS and BSABS, respectively. The overall agreement percentage of the relative functional impairment of the three groups (UHR+, not at risk of psychosis and psychosis) were 89.24%, 86.36% and 88.12%, respectively. The inter-rater reliability of the CAARMS, SIPS and BSABS total score was 0.90, 0.89 and 0.85. The inter-rater reliability was very good to excellent for all the subscales of these three instruments. For CAARMS, SIPS and BSABS, the kappa coefficient about UHR criteria agreement was 0.87, 0.84 and 0.82, respectively (P < 0.001). The transition rates of UHR+ to psychosis within 2 years were 16.7% (CAARMS), 10.0% (SIPS) and 17.7% (BSABS).
Conclusion: There is good diagnostic agreement between the CAARMS, SIPS and BSABS towards identification of UHR participants who are close relatives of patients with schizophrenia.
Keywords: Predictive analysis; Psychometric diagnostic; Psychosis; Psychosis-Risk syndrome; Ultra-high risk.
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