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Premenstrual dysphoric disorder (PMDD) is a female-specific condition classified in the Diagnostic and Statical Manual—5th edition under depressive disorders. Alterations in grey matter volume, cortical thickness and folding metrics have been associated with a number of mood disorders, though little is known regarding brain morphological alterations in PMDD. Here, women with PMDD and healthy controls underwent magnetic resonance imaging (MRI) during the luteal phase of the menstrual cycle. Differences in grey matter structure between the groups were investigated by use of voxel- and surface-based morphometry. Machine learning and multivariate pattern analysis were performed to test whether MRI data could distinguish women with PMDD from healthy controls. Compared to controls, women with PMDD had smaller grey matter volume in ventral posterior cortices and the cerebellum (Cohen’s d = 0.45–0.76). Region-of-interest analyses further indicated smaller volume in the right amygdala and putamen of women with PMDD (Cohen’s d = 0.34–0.55). Likewise, thinner cortex was observed in women with PMDD compared to controls, particularly in the left hemisphere (Cohen’s d = 0.20–0.74). Classification analyses showed that women with PMDD can be distinguished from controls based on grey matter morphology, with an accuracy up to 74%. In line with the hypothesis of an impaired top-down inhibitory circuit involving limbic structures in PMDD, the present findings point to PMDD-specific grey matter anatomy in regions of corticolimbic networks. Furthermore, the results include widespread cortical and cerebellar regions, suggesting the involvement of distinct networks in PMDD pathophysiology.

Premenstrual dysphoric disorder (PMDD) is a debilitating disorder characterized by severe mood symptoms in the luteal phase of the menstrual cycle. PMDD symptoms are hypothesized to be linked to an altered sensitivity to normal luteal phase levels of allopregnanolone (ALLO), a GABAA-modulating progesterone metabolite. Moreover, the endogenous 3β-epimer of ALLO, isoallopregnanolone (ISO), has been shown to alleviate PMDD symptoms through its selective and dose-dependent antagonism of the ALLO effect. There is preliminary evidence showing altered recruitment of brain regions during emotion processing in PMDD, but whether this is associated to serum levels of ALLO, ISO or their relative concentration is unknown. In the present study, subjects with PMDD and asymptomatic controls underwent functional magnetic resonance imaging (fMRI) in the mid-follicular and the late-luteal phase of the menstrual cycle. Brain responses to emotional stimuli were investigated and related to serum levels of ovarian steroids, the neurosteroids ALLO, ISO, and their ratio ISO/ALLO. Participants with PMDD exhibited greater activity in brain regions which are part of emotion-processing networks during the late-luteal phase of the menstrual cycle. Furthermore, activity in key regions of emotion processing networks - the parahippocampal gyrus and amygdala - was differentially associated to the ratio of ISO/ALLO levels in PMDD subjects and controls. Specifically, a positive relationship between ISO/ALLO levels and brain activity was found in PMDD subjects, while the opposite was observed in controls. In conclusion, individuals with PMDD show altered emotion-induced brain responses in the late-luteal phase of the menstrual cycle which may be related to an abnormal response to physiological levels of GABAA-active neurosteroids.

Background: Emotion regulation deficits have been highlighted as a transdiagnostic feature of multiple psychiatric disorders. Deficient prefrontal “top-down” regulation of key nodes of the salience network (SN) associated with emotion generation, has previously been hypothesized to be relevant also in premenstrual dysphoric disorder (PMDD).

Methods: In the present study, we used functional magnetic resonance imaging (fMRI) to investigate menstrual-cycle related variations in brain activity and connectivity in response to two separate emotional tasks (emotion reactivity and regulation) in 29 women with PMDD and 27 controls. We also examined whether differential brain activation between groups is related to premenstrual symptom severity and serum levels of progesterone-derived neuroactive steroids.

Results: We did not find convincing evidence for reduced activity in regions associated with the conscious control of emotion in PMDD. However, women with PMDD showed increased reactivity in key nodes of the SN and the default mode network (DMN) during the luteal phase compared to control women. Furthermore, SN hyperactivity was apparent also during the follicular phase and related to PMDD symptom severity. We found no evidence of altered network connectivity across the menstrual cycle in PMDD women.

Conclusion: SN dysfunction during the luteal phase may mediate multiple network aberrations. Furthermore, higher baseline (follicular) SN activity may render PMDD women more susceptible to severe mood symptoms in response to hormonal fluctuations. What drives increased SN activity in the follicular phase is unknown, but innate and neuroplastic mechanisms are proposed.

Background: Premenstrual dysphoric disorder (PMDD) has been hypothesized to be related to an abnormal sensitivity of the g-aminobutyric acid type A (GABAA) receptor to progesterone-derived neurosteroids. GABAA receptor sensitivity to neurosteroid-modulation is dependent on its subunit composition.

Methods: In the present study, we used quantitative reverse transcription polymerase chain reactions (RT-qPCR) to compare messenger ribonucleic acid (mRNA) expression of GABAA receptor subunits in peripheral mononuclear cells (PBMCs) across the menstrual cycle in 29 women with PMDD and 27 controls. We related mRNA subunit expression to serum levels of neurosteroids, and to functional activation of the amygdala, a key brain region involved in emotion generation, measured using functional magnetic resonance imaging (fMRI).

Results: Women with PMDD had lower mRNA expression of the delta GABAA receptor subunit during the luteal phase of the menstrual cycle. Lower delta mRNA expression was related to higher amygdala activation in PMDD women.

Conclusion: GABAA receptor incorporating the delta subunit are especially sensitive to neurosteroids modulation. It is possible that the mood symptoms of PMDD are mediated by an inability to effectively adjust the expression of this receptor type in response to neurosteroids fluctuations, leading to dysregulation GABAergic tone and increased activity in emotion-generating brain circuits.