Development of a measure quantifying adverse psychotherapeutic ingredients: the Experiences of Therapy Questionnaire (ETQ).

While psychotherapies are of established value, they may, as active treatments, risk adverse outcomes. As there is no validated measure of potentially negative psychotherapeutic ingredients, we sought to develop such a measure for use in psychotherapy evaluation studies. Based on a review of the literature, a 103-item experiential measure was derived. Psychometric properties and scale score correlates were examined in a sample of more than 700 respondents. Principal component analyses revealed a five-factor solution, explaining 53.4% of the variance; namely 'Negative Therapist', 'Pre-occupying Therapy', 'Beneficial Therapy', 'Idealization of Therapist' and 'Passive Therapist' constructs. Derived factors had high internal consistency, and scale scores were correlated with a number of clinically relevant demographic and treatment characteristics. An independent study established high test-retest reliability for the measure. Assessment of any adverse effects of psychotherapy is of clinical and research significance. We report the development of a measure that should allow the impact of such effects to be quantified in treatment studies, and especially in apportioning the contribution of such non-specific therapeutic effects.