Derogatis Interview for Sexual Functioning

Abstract

The Derogatis Interview for Sexual Functioning (DISF) is a brief, gender-keyed, semistructured interview designed to provide a quantitative assessment of an individual’s current quality of Sexual Functioning. The instrument is multidimensional, composed of 26 items organized into five functional domains that broadly parallel the phases of the Sexual Response Cycle. A parallel 26-item self-report version, the DISF-SR, is also available, allowing for matched clinician and patient assessments. Both versions utilize standardized scores based on non-patient community norms, specifically employing area t-scores to facilitate accurate percentile comparisons and detailed profile evaluation of strengths and weaknesses across domains.

The DISF and DISF-SR are designed for interpretation at three levels: the discrete item level, the functional domain level, and the global summary (total score) level. They have demonstrated favorable Psychometric Characteristics and are suitable for repeated use in clinical efficacy and effectiveness trials without significant practice effects.

Keywords

Sexual Functioning, Sexual Dysfunction, DISF, DISF-SR, Leonard R. Derogatis, Psychometric Scale, Sexual Response Cycle, Clinical Psychometric Research, Inc.

Authors

Leonard R. Derogatis

Purpose

The primary purpose of the Derogatis Interview for Sexual Functioning (DISF) and its self-report counterpart (DISF-SR) is to serve as a set of brief, gender-keyed, and multi-dimensional outcome measures. These instruments were developed to address the clinical and research need for standardized tools capable of representing the status of an individual’s current sexual functioning in quantitative terms.

The scales facilitate evaluation at multiple interpretive levels, allowing clinicians and researchers to assess specific performance deficiencies (discrete item level), general domain function (e.g., Sexual Arousal score), and overall quality of sexual functioning (global total score). This structure makes the instruments highly suitable for use in efficacy trials, such as corporate-sponsored clinical drug trials, where sequential assessment of change over time is crucial.

Construct

The DISF measures the quality of an individual’s current sexual functioning, conceptualized as a multidomain construct that broadly aligns with established models of the sexual response cycle (e.g., Masters & Johnson, 1966). The overall construct of sexual functioning is decomposed into five primary, yet relatively independent, functional domains.

The 26 items in both the DISF and DISF-SR are categorized into the following five domains:

• I. Sexual Cognition/Fantasy: Measures mental engagement and desire related to sexual activity.
• II. Sexual Arousal: Assesses the physiological and psychological experience of arousal.
• III. Sexual Behavior/Experience: Covers the practical aspects and frequency of sexual activity.
• IV. Orgasm: Focuses on the ability to achieve and the quality of orgasmic experience.
• V. Sexual Drive/Relationship: Addresses overall libido and the relational context of sexual activity.

Validity

The validity profile of the DISF and DISF-SR is strongly supported by the pattern of inter-domain and domain-total score correlations, a critical demonstration for multidimensional psychological outcome measures related to construct validity. The scales consistently demonstrate a pattern that approaches the theoretical optimum for measuring distinct yet related dimensions.

Data derived from “normal” non-patient samples and sexually dysfunctional samples confirm that the mean interdomain correlation coefficients are relatively low, ranging from 0.23 to 0.39. This low correlation suggests that the five functional domains are measuring relatively independent aspects of sexual functioning, minimizing conceptual redundancy. Conversely, the average domain-total correlations range from 0.60 to 0.71, indicating that each domain contributes substantial, independent variance to the overall DISF total score, thereby confirming their status as valid components of the higher-order construct of Quality of Sexual Functioning.

Clinical validation studies, including those involving males undergoing radiation therapy for prostate cancer, have further confirmed the instrument’s utility. In one study, the DISF demonstrated high clinical utility as a screening tool for impotence, yielding a sensitivity of 86%, a specificity of 80%, and a positive predictive value of 86%. Furthermore, DISF domain scores were significantly different across post-treatment functional categories (totally functional, marginally functional, and impotent), confirming its ability to validly reflect differences in sexual functioning quality subsequent to therapeutic intervention.

Reliability

Both the DISF interview and the DISF-SR self-report inventory exhibit favorable reliability profiles. The internal consistency coefficients for the individual subscales consistently range between 0.74 and 0.80, indicating good homogeneity among items within each domain.

Stability over time is demonstrated by high test-retest correlations, which were all reported to be above 0.80 over a 1-week interval. For the DISF interview version, interrater correlations were found to range favorably from 0.84 to 0.92, confirming that results are consistent across different clinical evaluators. These psychometric findings confirm the reliability and stability of the measurements derived from both versions of the scale.

Factor Analysis

Although formal factor analysis details were not provided, the scale’s structure is inherently multidimensional, based on five functional domains. The psychometric evidence strongly supports the independence of these domains. The low mean interdomain correlation coefficients (0.23 to 0.39) across various samples (normal and dysfunctional) suggest that the five domains operate as relatively distinct factors contributing non-redundant information to the total score.

This factor structure, derived from the correlation matrix analysis, ensures that clinicians can utilize the domain scores to pinpoint specific areas of dysfunction (e.g., profound decrement in a single domain like Sexual Arousal) without concern that the domains are merely overlapping measures of a single underlying factor.

Instrument

Test Type: Clinical Interview (DISF) and Self-Report Inventory (DISF-SR)

Format: 26 items structured via 4-point Likert-type scales.

Language Available: English, French, Italian, Spanish, Dutch, Danish, and Norwegian.

Population Group: General adult population (non-patient and patient samples).

Age Group: Adults (norms available for non-patient community respondents; development of geriatric norms was underway).

Population Details: Gender-keyed versions exist for men and women. Norms are based on several hundred non-patient community respondents and are presented as standardized area t-scores.

Test Methodology: The DISF is administered as a semistructured interview, typically requiring 15 to 20 minutes. The DISF-SR is a self-report questionnaire, generally requiring slightly less time. Both versions are designed for sequential administration in clinical trials without loss of validity.

Keywords

Area T-scores, Construct Validity, Sexual Arousal, Orgasm, Sexual Behavior, Psychometric Assessment, Outcome Measure, Likert Scale.

Authors

Author ORCID Identifier: Not provided in source content.

Affiliation Email addresses: [email protected]

Correspondence Address: Leonard R. Derogatis, Johns Hopkins Department of Psychiatry and Behavioral Sciences—Center for Sexual Medicine at Sheppard Pratt, Baltimore, MD 21285.

Permissions & Fee and Test Year

The DISF and DISF-SR instruments are distributed exclusively by Clinical Psychometric Research, Inc. (The official website for distribution information is: www.derogatis-tests.com).

The primary manual detailing scoring and administration procedures was published in 1996.

Reference’s

• Derogatis, L. R. (1996). Derogatis Interview For Sexual Functioning (DISF/DISF-SR): Preliminary scoring, procedures & administration manual. Baltimore, MD: Clinical Psychometric Research Inc.
• Masters, W. H., & Johnson, V. E. (1966). Human sexual response. Boston: Little, Brown.
• Messick, S. (1995). Validity of psychological assessment: Validation of inferences from person’s responses and performances as scientific inquiry into score meaning. American Psychologist, 50, 741–749.
• Zinreich, E. Derogatis, L. R., Herpst, J., Auvil, G., Piantodosi, S., & Order, S. E. (1990a). Pre- and posttreatment evaluation of sexual function in patients with adenocarcinoma of the prostate. International Journal of Radiation Oncology & Biological Physics, 19, 729–732.
• Zinreich, E. Derogatis, L. R., Herpst, J., Auvil, G., Piantodosi, S., & Order, S. E. (1990b). Pretreatment evaluation of sexual function in patients with adenocarcinoma of the prostate. International Journal of Radiation Oncology & Biological Physics, 19, 1001–1004.

Items of the Derogatis Interview for Sexual Functioning

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

Examples of discrete items used in the DISF/DISF-SR include:

• “A full erection upon awakening,”
• “Your ability to have an orgasm,”