Sexual Desire Inventory-2 (SDI-2)

Purpose and Primary Use:

The Sexual Desire Inventory-2 (SDI-2) is a self-report instrument designed to quantify sexual desire across different cognitive and behavioral dimensions. Its primary use is to provide a nuanced measure of an individual's sexual desire, distinguishing between dyadic desire (desire for sexual activity with a partner) and solitary desire (desire for sexual activity by oneself). It is intended for use by primary care physicians, sex therapists, psychologists, and researchers to assess aspects of sexual desire in clinical and research settings.

When to Use and Limitations:

The SDI-2 can be utilized when a clinician or researcher needs to evaluate an individual's level and type of sexual desire. This may be relevant in the context of diagnosing sexual dysfunctions (e.g., hypoactive sexual desire disorder), assessing the impact of medical conditions or medications on sexual desire, monitoring the effects of psychotherapeutic or pharmacological interventions, or as part of a comprehensive psychological evaluation. It is important to note that the SDI-2 is a self-report measure, and its accuracy depends on the respondent's honesty, insight, and recall. Cultural background and individual interpretations of sexuality may influence responses. The indicated score thresholds for 'hypersexuality' are suggestive guidelines based on the original research and are not definitive diagnostic criteria; clinical judgment is essential in interpreting scores.

Sources, References, and Literature:

The Sexual Desire Inventory-2 (SDI-2) is a well-established self-report questionnaire designed to measure various facets of sexual desire. Spector IP, Carey MP (1990), is attributed to the initial development of the SDI. The SDI-2 is a subsequent, refined version often attributed to Spector, Carey, and Steinberg in 1996. The SDI-2 is notable because it distinguishes between different dimensions of sexual desire, moving beyond a single "overall" score. In this foundational study, the authors described the development of the inventory, which aimed to create a psychometrically sound tool to measure sexual desire. Factor analysis supported a two-factor structure: Dyadic Sexual Desire and Solitary Sexual Desire. The study also provided evidence for the inventory's internal consistency and test-retest reliability.

Excerpt from the abstract: "The Sexual Desire Inventory (SDI) was developed to measure sexual desire in cognitive terms... Factor analyses indicated that a two-factor oblique solution best fit the data for both men and women. The two factors were labeled Dyadic Sexual Desire (desire for sexual activity with a partner) and Solitary Sexual Desire (desire for sexual activity by oneself). Evidence for internal consistency and test-retest reliability was strong."

Clinical Workflow and Parameters (Scoring):

The SDI-2 consists of 13 items. The patient responds to each item using a Likert-type scale. Points are assigned to each response option as indicated on the inventory form. 

Three scores are calculated:

• Dyadic Sexual Desire (DSD) Score: Calculated from the sum of scores for items 1-8.
  • Range: 0 to 62.
  • Interpretation: Higher scores indicate greater dyadic sexual desire. Scores at around 50 and upward may suggest hypersexuality in the dyadic dimension, though this is not a formal diagnostic threshold and requires clinical correlation.
• Solitary Sexual Desire (SSD) Score: Calculated from the sum of scores for items 9-13.
  • Range: 0 to 39.
  • Interpretation: Higher scores indicate greater solitary sexual desire. Scores at around 31 and upward may suggest hypersexuality in the solitary dimension, subject to clinical evaluation.
• SDI-2 Total Score: Calculated from the sum of scores for all 13 items (items 1-13) with a range of 0 to 101 points. This score provides an overall measure of sexual desire as captured by the inventory. No specific interpretive guidelines for hypersexuality are provided for the total score in the original SDI-2 documentation beyond it being a cumulative sum.

Clinicians should use these scores in conjunction with a broader clinical assessment, including patient history and interviews, to understand an individual's sexual desire profile.