Derogatis Sexual Functioning Inventory

Derogatis Sexual Functioning Inventory‌

LEONARD R. DEROGATIS,1 Clinical Psychometric Research, Inc.

The Derogatis Sexual Functioning Inventory (DSFI) measures constructs believed to be fundamental to successful sexual functioning (e.g., drive, body image, sexual satisfaction) and, in addition, measures several basic indicators of general well-being (e.g., affects balance and psychological distress).

Description

The DSFI is an “omnibus” self-report inventory designed to measure the quality of the current sexual functioning of an individual. The DSFI is multidimensional in nature because the comprehensive study of sexual functioning has revealed it to be a highly multidetermined behavior. Although apparently straightforward, successful human sexual functioning rests on a complex interplay of endocrine, emotional, cognitive, and experiential factors that preclude the simple enumeration of sexual episodes, or orgasms, as meaningful forms of measuring the quality of sexual functioning.

The individual respondent is the basis for evaluation by the DSFI in part because it represents the most parsimonious and straightforward unit to work with, and also because, regardless of context, quality of sexual functioning is ultimately appreciated by the individual. Current sexual functioning is the conceptual continuum for the DSFI because it comes closest to the central evaluative question in the clinical assessment of sexual disorder: “What is the current level and nature of the patient’s sexual functioning?” By quantifying the principal dimensions of the patient’s sexual experience in profile form, an insight is gained into both the nature and magnitude of the individual’s sexual dysfunction.

The DSFI is comprised of 10 substantive dimensions that are judged to reflect the principal components of sexual behavior. The conceptual basis for the DSFI was outlined by Derogatis in 1976, and several subsequent monographs have been published on the instrument (Derogatis, 1980; Derogatis & Melisaratos, 1979). Of the 10 subtests constituting the DSFI, two of them, Psychological Symptoms and Affects are themselves complete, multidimensional tests. The Brief Symptom Inventory (BSI; Derogatis, 1993) and the Derogatis Affects Balance Scale (ABS; Derogatis, 1975; Derogatis & Rutigliano, 1996) provide measurement of psychological distress and mood and affects, respectively.

Since its introduction in the mid-1970s, the DSFI has been utilized as an outcome measure in multiple empirical studies of sexual functioning (see references). In most instances, dimension or global score measures from the instrument have proven sufficiently sensitive to discriminate differences in the groups under study. Discriminations have ranged from relatively large effect sizes (e.g., comparisons of gender-dysphoric patients with normal heterosexuals) to much more demanding discriminations (e.g., sexual functioning in diabetic vs. normal women, inflatable vs. noninflatable prostheses in penile implant surgery).

Response Mode

The DSFI is composed of 254 items, arranged into 10 subtests. Formats vary from simple endorsements of yes or no to multiple-point Likert-type scales.

DSFI Dimensions and Global Score Descriptions

Information. The Information subtest consists of a 26- item subtest in true-false format that measures the level of accurate information possessed by the respondent concerning the physiology, anatomy, and other aspects of sexual functioning. A single information score is determined as the sum of the number of correct responses.

Experiences. The Experiences subtest consists of a list of 24 sexual behaviors ranging from very fundamental behaviors to various forms of sexual intercourse and oral-genital activities. The respondent indicates which behaviors he/ she has experienced lifetime, and which experiences have occurred during the past 60 days. The Experiences score is the sum of lifetime experiences.

Drive. The Drive subtest is a composite summary measure of libidinal erotic interests expressed in the five behavioral domains of sexual intercourse, masturbation, kissing and petting, sexual fantasy, and ideal frequency of intercourse. The respondent indicates the frequencies of these behaviors during the current period. A single Drive score is developed by summing across domains.

Attitudes. Based upon work showing liberal and conservative sexual attitudes to be predictive of quality of sexual functioning, the Attitudes subtest is comprised of 30 items (15 liberal items and 15 conservative items) represented on 5- point Likert-type scales. The respondent indicates the degree to which he/she is in agreement with each item. Liberal, conservative, and total attitude scores are generated.

Address correspondence to Leonard R. Derogatis, Johns Hopkins Department of Psychiatry and Behavioral Sciences––Center for Sexual Medicine at Sheppard Pratt, Baltimore, MD 21285; e-mail: [email protected]

Psychological Symptoms. Psychological distress is measured by the 53 items of the Brief Symptom Inventory (BSI). Each symptom of the BSI is represented on a 5- point scale from not at all (0) to extremely (4). Scores are summed across items to achieve a single Symptoms score. The BSI may optionally be scored for the nine dimensions (e.g., Depression, Anxiety) and global scores that underlie the items of the BSI.

Affects. The Affects subtest is also a complete multi- dimensional test termed the Derogatis Affects Balance Scale (DABS). The DABS measures affect and mood through 40 adjective items endorsed by the respondent. Twenty items represent positive affects, and 20 items reflect negative affects. Scores include a Positive Affects total, a Negative Affects total and the overall Affects Balance Index. The latter is used as the affects measure for the DSFI.

Gender Role Definition. Consistent with the concept that masculinity and femininity are components of all individuals’ gender role definitions, the two primary components of gender role are each measured in terms of 15 adjective items that the respondent endorses in varying degrees. A Masculinity score, a Femininity score, and a Gender Role Definition score are determined.

Fantasy. This subtest consists of 20 major sexual themes that have been culled from research on normal sexual fantasies as well as fantasies arising from clinical variations on routine sexual behaviors. The Fantasy score consists of a simple summation of the items endorsed.

Body Image. Body image has been demonstrated to be an integral aspect of self-concept and, as such, is an important determinant of successful sexual functioning. It is measured in the DSFI in terms of 15 items, 10 common and 5 gender- keyed, that reflect the individual’s level of appreciation of his/her body. A single Body Image score is developed.

Sexual Satisfaction. The Sexual Satisfaction subtest is itself multidimensional in nature, being comprised of a number of distinct components (e.g., frequency of intercourse, quality of communication, quality of orgasm). Ten true-false items comprise the Satisfaction subtest, each reflecting whether the respondent is satisfied with that specific aspect of his/her sexual functioning. A single Satisfaction score is calculated as a sum of endorsements indicating satisfaction with a particular component.

SFI: The DSFI total score. The Sexual Functioning Index (SFI) is the total or global summary score of the DSFI. It is calculated as a direct unweighted linear combination of the 10 subtest or principal dimension scores. Because subtest scores are calculated along very different score continua, and some are gender-keyed (i.e., distinct for men and women), subtest scores are first transformed to area t– scores (μ = 50; SD = 10) before being summed to achieve the SFI. Because the transformation is a normalizing, area (under the curve) type, the actuarial characteristics of the resulting standardized distribution are retained.

The Global Sexual Satisfaction Index (GSSI). The GSSI is the second global measure of the DSFI, and it is quite different in nature from the SFI or DSFI total score. Whereas the DSFI total score reveals the respondent’s quality of sexual functioning in psychometric terms, the GSSI reflects the individual’s subjective perception of his/her sexual behavior. The GSSI represents quality of sexual functioning on a 9-point scale anchored at the lower extreme by 0, could not be worse to 8, could not be better at the upper limit. Each scale point is characterized by a descriptive phrase, and the respondent is provided an opportunity to globally summarize his/her perception of the quality of sexual behavior in straightforward terms.

Normative Population. Norms for the DSFI were developed based on a sample of 230 individuals in attendance at university continuing education classes. The majority of the sample were White (80%) and middle-aged, (M = 32) with some college education. Approximately 60% of the sample were married at the time of assessment, with the majority (75%) coming from middle-class and upper-middle-class backgrounds.

Reliability and Validity

Published studies by both the author of the scale and numerous other investigators suggest the DSFI is highly reliable and is a valid measure of the construct of sexual functioning. Derogatis and Melisaratos (1979) reported internal consistency reliability coefficients based on an N of 325 between .60 and .97, and test-retest coefficients across a 14-day interval ranging predominantly from the high .70s to the low .90s. Howell et al. (1987) also reported test-retest coefficients over a 14-day period, and all coefficients were > .70. Over four dozen published studies currently exist using the DSFI as a measure of functional discrimination and outcomes in a broad variety of medical treatment populations (see references). The majority show the DSFI to be highly sensitive to naturally occurring and disease- induced interference with sexual functioning, as well as positive treatment effects.

Other Information

The DSFI is available in Arabic, Chinese, English, French, French Canadian, Indian, Korean, Norwegian, Spanish, and Turkish. The DSFI is distributed exclusively by Clinical Psychometric Research, Inc. (www.derogatis-tests.com).

References