Gender dysphoria as a measure of proximal stress: Development and psychometric evaluation of a novel measure of social gender dysphoria. ABSTRACT The proposed research will focus on the development and psychometric evaluation of a new measure of social gender dysphoria and distress. Clinical/scientific understandings of gender dysphoria, and its measurement, have been conceptualized primarily through the incongruence of gender identity and assigned sex. Our developmental work has focused on transgender and nonbinary (TGNB) individuals’ critique of existing scales and their descriptions regarding their lived experience of gender dysphoria. Our findings suggest that scientific definitions are too narrowly defined, do not reflect the heterogeneity of experience within the community (Galupo & Pulice-Farrow, 2020), and fail to capture shifting and nonbinary aspects of gender dysphoria (Galupo, Pulice-Farrow, & Cusack, 2020; Galupo, Pulice-Farrow, & Pehl, 2021). We have also documented the ways that social stressors (e.g. discrimination and misgendering) elicit gender dysphoria, and have theorized that social dysphoria acts as a proximal stressor for physical and mental health disparities (Galupo, Pulice- Farrow, & Lindley, 2019). We have subsequently provided empirical support for gender dysphoria as a proximal stressor (Lindley & Galupo, 2020) and used this model to show that social dysphoria works with other proximal stressors to predict problematic substance use among TGNB individuals (Lindley, Bauerband, & Galupo, 2020). We propose to use this pilot work to develop and evaluate a novel measure of social gender dysphoria and distress. Our research team will work with both expert consultants and community panelists to generate and evaluate initial scale items (Aim 1), test and confirm structure, reliability, validity, and invariance of our novel measure of social gender dysphoria (Aim 2), and investigate the relation between social gender dysphoria and mental health outcomes (Aim 3). Our proposed measure of social gender dysphoria will allow a way to capture the role of gender dysphoria as a unique proximal stressor in models of minority stress for TGNB individuals. Our measure represents a critical theoretical and methodological innovation that will allow assessment of the role of gender dysphoria as it is elicited by discrimination and microaggressions (i.e., distal stressors) and is related to well established mental health disparities for TGNB individuals including depression, anxiety, substance use, and disordered eating. Such a measure will not only provide a critical tool for investigating mental health among TGNB individuals, but provide a clinical assessment tool of dysphoria- related distress.