Sexual health is a fundamental aspect of quality of life; a satisfying sexual relationship is linked to better physical, psychological, and relationship health and well-being. In fact, people who maintain a satisfying, active sex life over time live longer than those who report lower sexual frequency and satisfaction. Yet problems with sexual function are extremely common, especially for women: chronic difficulties with sexual desire and/or arousal that are personally upsetting-Sexual Interest/Arousal Disorder (SIAD)-affects 7% to 23% of the general population. SIAD is linked to more healthcare costs, depressive symptoms and anxiety, and lower relationship satisfaction. Experts suggest that relationship factors play a critical role in SIAD and couple-based sex therapy is a common approach used by clinicians. However, there are no treatment options available for couples that have been tested in research to confirm that they work. The goal of this three-centre randomized clinical trial is to evaluate the efficacy of a novel 16-session cognitive-behavioural couple therapy (CBCT), offered online to increase accessibility, for an inclusive sample of women with SIAD compared to a waitlist control group. The investigators expect that, compared to a waitlist control group, CBCT will lead to greater improvements in SIAD symptoms (e.g., higher sexual desire/arousal, lower sexual distress) and better sexual, relational, and psychological adjustment for both partners at post-treatment and 6-months later. Given that less than a third of those affected by SIAD access treatment, this study addresses the urgent need for an accessible couple-based treatment for the most common sexual dysfunction. Results will be used by clinicians to provide couples with a scientifically based, accessible treatment option, that will improve their sexual, relationship, and psychological health.

Background and Importance. Sexual health is a fundamental aspect of overall quality of life; a satisfying sexual relationship is associated with better physical, psychological, and relationship health and well-being. In fact, people who maintain a satisfying, active sex life over time live longer than those who report lower sexual frequency and satisfaction. Yet problems with sexual function are extremely common, especially for women: persistent difficulties with sexual desire and/or arousal that are personally distressing-Sexual Interest/Arousal Disorder (SIAD9)-affects 7% to 23% of the general population. SIAD is linked to greater healthcare costs, depressive symptoms, and lower relationship satisfaction. Sexual desire-the key component in SIAD-is thought to be embedded in, and influenced by, interpersonal factors, more so for women than for men. Although theoretical and clinical models suggest a significant role for interpersonal processes in SIAD, there is a striking neglect of these factors in available treatments. Couple-based sex therapy is commonly used by clinicians, but no study to date has assessed its efficacy for SIAD. The current proposal builds on our ongoing CIHR-funded work examining interpersonal factors in SIAD, as well as the results of our pilot study.

Aims. The primary aim of this three-centre randomized clinical trial is to test the prediction that a novel cognitive-behavioural couple therapy (CBCT) delivered online will yield significantly greater improvements in primary outcomes of sexual desire and sexual distress for women and individuals with SIAD post-treatment and 6-months later, compared to a waitlist control group. Our secondary aim is to test the prediction that couples receiving CBCT will report greater improvements in sexuality, relationship, and psychological outcomes relative to the control group.

Methods/Approach/Expertise. The investigators will: (1) recruit an inclusive sample of 170 women diagnosed with SIAD via a clinical interview, and their partners; (2) randomize couples to either the 16-session CBCT or a waitlist control group; (3) have couples complete standardized, self-report measures at pre-treatment, post-treatment, and 6-month follow-up as well as approximately every 4 weeks during the treatment period; (4) test the efficacy of CBCT compared to the control group. Procedures will take place at Dalhousie University, Université de Montréal, and the University of British Columbia.

Expected Outcomes. This clinical trial addresses the urgent need for an empirically validated, accessible, couple-based treatment for the most prevalent sexual dysfunction-SIAD. Results will be used by clinicians to provide affected couples with a scientifically-based treatment option that will improve their sexual, relationship and psychological well-being.

Inclusion Criteria:

• One member of the couple must identify as a cisgender woman, a trans woman, or a gender diverse person assigned female at birth;
• One member of the couple must meet diagnostic criteria for SIAD;
• Both partners must be fluent in English or French;
• Both partners must be in a committed, cohabiting relationship for at least one year (with a partner of any gender/sex).

Exclusion Criteria:

• Pregnancy, breastfeeding or one year postpartum;
• No prior sexual experience;
• Severe relational distress or conflict as determined by baseline measures and interview;
• Are currently undergoing treatment for SIAD, or are in couple or sex therapy.

Since this study is about women's low sexual desire and/or arousal, the investigators are recruiting couples in which one member is a cisgender woman, trans woman, or gender diverse person assigned female at birth.

Participants will be randomized to one of the two study arms before treatment initiation (max 2 weeks delay) using a stratified method, based on the treatment site. Assignments will be made by a free randomization software (www.studyrandomizer.com). In each site, allocation will be computer-generated randomly using permuted blocks of size 6 (fixed) to maintain equilibrium between the two conditions (treatment and control). This procedure ensures that the personnel conducting evaluations will not be aware of participant condition and that the PIs will not influence the randomization process. Data analysts will be masked until the end of all analyses. Participants will be instructed not to reveal the condition they are in.