Abstract
INTRODUCTION: The early identification of psychosis risk is critical, particularly within the first 2 years of the at-risk phase, as timely intervention may reduce the likelihood of transitioning to psychosis. This study evaluates the reliability and validity of the Spanish version of the Comprehensive Assessment of At-Risk Mental States (CAARMS-S) interview. METHODS: A prospective longitudinal study was conducted with 36 individuals at ultra-high risk (UHR), 43 with First-Episode Psychosis (FEP), and 14 matched controls, all of whom were part of the Early Intervention Program in Catalonia. Data collection involved clinical interviews and multiple validated scales, including the CAARMS-S, the Positive and Negative Syndrome Scale (PANSS), the Global Assessment of Functioning (GAF), the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II), and the Kiddie-Schedule for Affective Disorders and Schizophrenia (K-SADS-PL). RESULTS: Reliability testing showed excellent internal consistency (Cronbach's α = 0.93) and inter-observer reliability [intraclass correlation coefficient (ICC) = 0.92]. Construct validity was supported by significant differences in PANSS positive subscale scores among UHR, FEP, and control groups (p < 0.001). Strong correlations were observed between CAARMS-S and PANSS subscales (positive: r = 0.608; negative: r = 0.495; general: r = 0.577). After 6 months, only one UHR participant (3.3%) transitioned to psychosis. Both CAARMS-S and PANSS were sensitive to changes in positive symptoms, with CAARMS-S being more responsive to negative symptoms and PANSS to general psychopathology. DISCUSSION: These findings confirm that CAARMS-S is a reliable, valid, and sensitive tool for identifying and monitoring individuals at risk of psychosis in Spanish-speaking clinical settings, supporting its use in early intervention programs.