Examining the Effects of Estradiol on Neural and Molecular Response to Rewards in Perimenopausal-Onset Anhedonia and Psychosis

Project Summary Affective disorders are highly prevalent in women and associated with significant morbidity and mortality, particularly during times of reproductive transition, including the transition to menopause. Unraveling the pathophysiology of affective disorders is challenging because depressive syndromes are heterogeneous and have diverse etiologies. Thus, studies aimed at identifying biomarkers to improve the prediction of susceptibility and illness course as well as treatment response in affective disorders have yielded inconsistent results. We propose to address this challenge by studying symptoms that initially present during the menopause transition and thus have a common endocrine trigger. We believe that studying a relatively homogeneous group of participants with similar biological mechanisms of symptom onset will increase the likelihood of elucidating the pathogenesis of perimenopausal-onset symptoms. This proposal will use simultaneous positron emission tomography and functional magnetic resonance imaging (PET-MR) to examine relations between reward-related striatal activation measured by fMRI and tonic and phasic striatal DA activity measured by [11C]raclopride PET in a transdiagnostic sample of women with varying severities of perimenopausal-onset (PO) anhedonia and psychosis. Specific Aim 1 will examine associations between PO anhedonia and psychosis symptom severity and reward-related striatal activation measured by fMRI and tonic and phasic striatal DA activity measured by [11C]raclopride PET. Specific Aim 2 will examine relations between anhedonia reductions due to estradiol administration, relative to placebo, and changes in PET-MR metrics related to reward processing. Specific Aim 3 will examine relations between PO psychosis reductions due to estradiol, relative to placebo, and changes in PET-MR metrics related to reward processing. Our central hypotheses are that the mesolimbic dopamine system is impaired during reward processing in PO anhedonia and psychosis, that the effects of estradiol administration will be associated with normalization of neural responses to rewards measured by fMRI and striatal dopamine functioning measured by PET, and that the degree of change in striatal functioning measured by fMRI and PET will be associated with the magnitude of change in PO anhedonia and psychosis symptom severity. The results of this project will increase our understanding of anhedonia and psychosis vulnerability during the menopause transition and have the potential to deliver validated molecular imaging targets to use in future mechanistic clinical trials of novel treatments for perimenopausal-onset psychiatric disorders.