Objective: The aim of this study was to adapt the Negative Effects Questionnaire (NEQ) into the Czech context and to assess its psychometric properties as well as the extent to which it covers important areas of the negative aspects of psychotherapy. Method: A total of 226 respondents answered an online survey. Confirmatory and exploratory factor analyses were conducted to assess the NEQ factor structure. Thematic analysis was used to analyze the open-ended NEQ item. Results: In terms of confirmatory factor analysis, the six-factor model proposed by the authors of the NEQ did not demonstrate an adequate fit. In a subsequent exploratory factor analysis, a more parsimonious, five-factor solution was proposed instead. Furthermore, a thematic analysis revealed some areas underrepresented in the NEQ, particularly clients' relationships with their relatives. Conclusions: The NEQ is a reliable instrument with a high added value for research and practice. Several directions for future development are suggested.
Keywords: adverse effects of psychotherapy; negative effects of psychotherapy; negative effects questionnaire.