Translation and validation of the Greek version of the Outcome Questionnaire-45.2

The present study aimed to translate and validate the original English version of the Outcome Questionnaire (OQ-45.2) for use in the Greek context. A sample of 385 psychotherapy trainees (102 men and 283 women), aged 18 to 65 years, was recruited from a systemic/family psychotherapy training center in Greece. Participants completed the Greek version of the OQ-45.2 (OQ-45.2-GR), the World Health Organization Quality-of-Life Scale (WHOQOL-BREF), and a demographic questionnaire. Confirmatory factor analysis supported a three-factor structure consistent with the original English version, yielding satisfactory robust fit indices (χ2/df, p = .001; RMSEA = .060; SRMR = .091). The OQ-45.2-GR demonstrated high internal consistency (Cronbach’s α = .912) and acceptable test-retest reliability (r = .64, p < .01). Concurrent validity was evidenced through significant negative correlations between the OQ-45.2-GR and WHOQOL-BREF total and subscale scores (r ranging from -.29 to -.69, p < .01). These findings provide preliminary evidence for the reliability and validity of the OQ-45.2-GR as a measure of psychotherapy outcomes in Greek-speaking populations. The OQ-45.2 is a widely utilized instrument for evaluating psychotherapy outcomes and serves additionally as a screening tool to assess client needs at therapy initiation, thereby informing clinical decision-making and optimizing treatment planning. The availability of a validated Greek version of the OQ-45.2 is expected to enhance clinical assessment practices, contribute to evidence-based treatment planning, and facilitate further research into psychotherapy processes and outcomes within Greece.