Mood disorders are among the leading causes of disease burden worldwide, with 20–70% of affected individuals experiencing comorbid premenstrual disorders. This systematic review and meta-analysis investigated the comorbidity of premenstrual dysphoric disorder (PMDD) or premenstrual syndrome (PMS) with non-reproductive mood disorders.

We aimed to determine the pooled prevalence of PMDD/PMS with adult mood disorders, assess the impact of comorbidity on clinical course and summarise the associated neurobiological findings.

Eligible studies were identified through Embase, MEDLINE and APA PsycINFO from inception to 22 January 2024 (PROSPERO, no. CRD42021246796). Studies on women (‘females‘) with diagnoses of PMDD/PMS and mood disorders were included. Risk of bias was assessed using National Institutes of Health quality assessment tools. A random-effects, pooled-prevalence meta-analysis was conducted using the Comprehensive Meta-Analysis software, categorising diagnostic sampling strategies as follows: mood disorders diagnosed first, PMDD/PMS diagnosed first or concurrent diagnoses. A narrative synthesis explored secondary outcomes, including illness course and biomarkers.

A total of 39 studies were included, with 36 of these (n = 3646) contributing to the meta-analysis. Seven studies focused on bipolar disorders, 18 on unipolar depressive disorders and 14 on mixed samples of bipolar and unipolar disorders. Random-effects pooled-prevalence meta-analyses showed consistently high comorbidity rates between PMDD/PMS and mood disorders, ranging from 42% (95% CI: 30%, 55%) to 49% (95% CI: 38%, 60%) across sampling strategies. Risk of bias varied, with methodological heterogeneity noted.

This review underscores high comorbidity rates between PMDD/PMS and mood disorders, regardless of sampling strategy, and highlights the need for research into clinical and neurobiological characteristics specific to this comorbidity. Limitations include study heterogeneity, reliance on cross-sectional designs and provisional PMDD/PMS diagnoses. Future research should address these gaps to inform diagnostic and therapeutic advancements tailored to this population.

Several lines of evidence suggest that bipolar disorder (BD) is associated with white matter (WM) pathology. Investigation of unaffected first-degree relatives of BD patients may help to distinguish structural biomarkers of genetic risk without the confounding effects of burden of illness, medication or clinical state. In the present study, we applied tract-based spatial statistics to study WM changes in patients with BD, unaffected siblings and controls.

A total of 27 euthymic patients with BD type I, 20 unaffected siblings of bipolar patients and 29 healthy controls who did not have any current or past diagnosis of Axis I psychiatric disorders were enrolled in the study.

Fractional anisotropy (FA) was significantly lower in BD patients than in the control group in the corpus callosum, fornix, bilateral superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, anterior thalamic radiation, posterior thalamic radiation, cingulum, uncinate fasciculus, superior corona radiata, anterior corona radiata and left external capsule. In region-of-interest (ROI) analyses, we found that both unaffected siblings and bipolar patients had significantly reduced FA in the left posterior thalamic radiation, the left sagittal stratum, and the fornix compared with healthy controls. Average FA for unaffected siblings was intermediate between the healthy controls and bipolar patients within these ROIs.

Decreased FA in the fornix, left posterior thalamic radiation and left sagittal stratum in both bipolar patients and unaffected siblings may represent a potential structural endophenotype or a trait-based marker for BD.