D Schermuly-Haupt [30], the instrument is more of a tool for improving the therapist’s ability to detect negative effects than a scale with distinguishable psychometric properties, although it has been used in at least one clinical trial [42].PLOS ONE | DOI:10.1371/journal.pone.0157503 June 22,3 /The Negative Effects QuestionnaireAs for other instruments, the RG7666 solubility Inventory for the Assessment of Negative Effects of Psychotherapy (INEP) has also been put forward [43]. After performing a literature review and consulting psychotherapy researchers, 120 items were generated (scored on a three-step scale regarding change or a four-step scale in terms of agreement), such as, “I feel addicted to my therapist” (Item 10). Of these, 52 items were selected and distributed to 195 patients that had undergone psychological treatment and who were recruited via advertisements. Using a principal component analysis and a confirmatory factor analysis, the results yielded a rotated solution of five or seven components/factors, depending on the type of analysis; intrapersonal changes, intimate relationship, stigmatization, emotions, workplace, therapeutic malpractice, and family and friends, accounting for 46.7 or 55.8 of the variance (the final version consists of 21 items). Interestingly, the results indicated that more patients in behavioral than psychodynamic or nondirective therapy felt forced by their therapist to implement certain interventions, while patients in nondirective therapy had longer periods of depression after the treatment period, and patients in psychodynamic therapy more frequently felt offended by their therapist. Although carefully developed and providing some useful recommendations, most notably, asking the patient to differentiate between negative effects of their treatment and other circumstances, the INEP is difficult to score and assess in relation to treatment outcome as it does not include a clear and coherent scale. Further, several items could be criticized on theoretical grounds, for instance, “I have order P144 Peptide trouble finding insurance or am anxious to apply for new insurances” (Item 8), as it might not always be applicable in different contexts. Also, a large number of items seem to convey malpractice issues, such as, “My therapist attacked me physically” (Item 19), and not negative effects of properly performed psychological treatments. Although they most certainly will have a negative impact, it could be argued that malpractice issues are related to the unethical behavior of a therapist rather than a feature of the treatment interventions [11]. Hence, in order to address some of the shortcomings that have been mentioned, a new instrument for assessing negative effects of psychological treatments was developed: the Negative Effects Questionnaire (NEQ). Items were generated by consulting a number or researchers [32], distributing open-ended questions [42], analyzing patient responses using qualitative method [44], and a comprehensive literature review. The purpose of this process was to present an instrument that is based on both theoretical considerations and empirical findings, with items being systematically derived, reasonable to expect, and comprehensible for the patient. The overall purpose of the current study is to determine the validity and factor structure of the instrument, and to examine what items should be retained in a final version. This is believed to result in an instrument that is accessible and easier to administer b.D Schermuly-Haupt [30], the instrument is more of a tool for improving the therapist’s ability to detect negative effects than a scale with distinguishable psychometric properties, although it has been used in at least one clinical trial [42].PLOS ONE | DOI:10.1371/journal.pone.0157503 June 22,3 /The Negative Effects QuestionnaireAs for other instruments, the Inventory for the Assessment of Negative Effects of Psychotherapy (INEP) has also been put forward [43]. After performing a literature review and consulting psychotherapy researchers, 120 items were generated (scored on a three-step scale regarding change or a four-step scale in terms of agreement), such as, “I feel addicted to my therapist” (Item 10). Of these, 52 items were selected and distributed to 195 patients that had undergone psychological treatment and who were recruited via advertisements. Using a principal component analysis and a confirmatory factor analysis, the results yielded a rotated solution of five or seven components/factors, depending on the type of analysis; intrapersonal changes, intimate relationship, stigmatization, emotions, workplace, therapeutic malpractice, and family and friends, accounting for 46.7 or 55.8 of the variance (the final version consists of 21 items). Interestingly, the results indicated that more patients in behavioral than psychodynamic or nondirective therapy felt forced by their therapist to implement certain interventions, while patients in nondirective therapy had longer periods of depression after the treatment period, and patients in psychodynamic therapy more frequently felt offended by their therapist. Although carefully developed and providing some useful recommendations, most notably, asking the patient to differentiate between negative effects of their treatment and other circumstances, the INEP is difficult to score and assess in relation to treatment outcome as it does not include a clear and coherent scale. Further, several items could be criticized on theoretical grounds, for instance, “I have trouble finding insurance or am anxious to apply for new insurances” (Item 8), as it might not always be applicable in different contexts. Also, a large number of items seem to convey malpractice issues, such as, “My therapist attacked me physically” (Item 19), and not negative effects of properly performed psychological treatments. Although they most certainly will have a negative impact, it could be argued that malpractice issues are related to the unethical behavior of a therapist rather than a feature of the treatment interventions [11]. Hence, in order to address some of the shortcomings that have been mentioned, a new instrument for assessing negative effects of psychological treatments was developed: the Negative Effects Questionnaire (NEQ). Items were generated by consulting a number or researchers [32], distributing open-ended questions [42], analyzing patient responses using qualitative method [44], and a comprehensive literature review. The purpose of this process was to present an instrument that is based on both theoretical considerations and empirical findings, with items being systematically derived, reasonable to expect, and comprehensible for the patient. The overall purpose of the current study is to determine the validity and factor structure of the instrument, and to examine what items should be retained in a final version. This is believed to result in an instrument that is accessible and easier to administer b.