Sexual Dysfunction Questionnaire: scale development and psychometric validation

Questionario sulle Disfunzioni Sessuali: sviluppo e validazione psicometrica della scala

R. Infrasca

Psychiatric Department, ASL 5 La Spezia, Italy


Sexual activity is an important dimension within quality of life. The fundamental psychological needs of an individual are represented by four psychodynamic factors: attachment, autonomy, sexual identity, and self-esteem. Sexual disorders are common in psychiatric patients and include desire, arousal, orgasmic, and pain disorders. Along with the positive aspects of human sexuality, however, mental illnesses can also affect an individual’s sexual health. We believe that this area of research lacks standard tools to highlight the presence of sexual problems and the associated personality traits in psychiatric patients (men and women). For these reasons, we developed a brief, practical, and simple selfreported questionnaire that would address most of the common sexual problems in psychiatric patients.


Following the methodology used in many research studies, we chose a list of items. The resulting 31-item questionnaire was administered to a sample of psychiatric patients (149 men and 333 women), to verify internal consistency and validity. We used factor analysis to identify underlying variables (or factors) that explain the pattern of correlation within a set of observed variables. Internal consistency of the questionnaire was assessed through Cronbach’s alpha coefficient. Twelve questions were shown to have no statistical significance. The final instrument consisted of 19 questions on a 5-point Likert scale: Always, Often, Sometimes, Rarely, and Never (see Appendix 1). Subjects were required to fill the 19-item questionnaire based on experiences from the previous 12 months. All subjects completed the MMPI, from which we obtained special scales for Low Self-esteem, Neuroticism, Anxiety Index, Ego Strength, Extroversion, and Sex Problems Scale (I-SP). The subjects were also required to complete the Toronto Alexithymia Scale (TAS-26), and the Eating Attitude Test (EAT- 26), an instrument used for the analysis of eating disorders.


The Sexual Dysfunction Questionnaire (SDQ) displayed excellent internal consistency, with a Cronbach alpha of 0.85. Kendall tau-b ranged from 0.19 to 0.38. The analysis of 19 items was run with Varimax rotation. In these results (Table I), the cumulative percentages show that the first two factors account for 99.58% of the variation. Multiple regression (Table II) highlighted that the personality involved in sexual problems is introverted, passive, or suspicious, with high anxiety, low self-esteem, and a high rate of neuroticism. Logistic regression (Table III) indicated that the probability of finding a sexual dysfunction increases 1.16 times for every point of increase in the score scale. Moreover, when the value of the scale is = 45 the probability of observing sexual issues is 8.16 times greater than when the scale values are < 44. A cut-off score of 45 matches a sensitivity of 88.4% and a specificity of 79.1%.


The psychometric data indicate that the SDQ is a valid, reliable, and satisfactory measure for describing sexual dysfunction in Psychiatric patients (men and women). Moreover, it is a brief self-report inventory, typically requiring 5 min of the patient’s time for completion and is well suited for use in both clinical and research settings

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