Association between insulin resistance and depression in women with polycystic ovary syndrome: a three-group comparative study

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in reproductive-aged women, often accompanied by metabolic disturbances such as insulin resistance (IR). Although emerging evidence suggests a link between PCOS and mental health disorders, the specific role of insulin resistance in depression and anxiety among affected women remains insufficiently understood. This study aimed to investigate the association between depression, anxiety, and insulin resistance in women with PCOS. This three-group cross-sectional comparative study was conducted among 274 women (aged 18–45 years) between June and December 2025 at a tertiary gynecology clinic and an infertility center in Ahvaz, Iran. Participants were divided into three groups: PCOS with insulin resistance (PCOS + IR; n = 87), PCOS without insulin resistance (PCOS-IR; n = 87), and healthy controls ( n = 100). PCOS was diagnosed based on the Rotterdam criteria. Insulin resistance was defined as HOMA-IR > 2.5. Depression and anxiety symptoms were assessed using the Beck Depression Inventory-II (BDI-II) and Beck Anxiety Inventory (BAI), respectively. Data were analyzed using one-way ANOVA, ANCOVA (adjusting for age, BMI, waist circumference, and socioeconomic status), and chi-square tests, followed by Bonferroni post-hoc comparisons. Effect sizes were reported as partial eta-squared (η²p). The three groups were comparable regarding education level, employment status, spouse’s occupation, and parity ( p > .05). However, significant differences were observed in age, body mass index (BMI), waist and hip circumference, blood pressure, and socioeconomic status (all p < .001). After adjustment for age, BMI, waist circumference, blood pressure, and socioeconomic status (hip circumference was excluded due to multicollinearity), depressive symptom scores differed significantly across groups (F(2, 265) = 10.59, p < .001, η² p = .074 indicating a medium effect size). Post-hoc analysis revealed that the PCOS + IR group had significantly higher depression scores than both the PCOS − IR group (Adjusted Mean Difference = 5.81, SE = 1.29, p < .001, 95% CI [2.71–8.92]) and healthy controls (Adjusted Mean Difference = 4.19, SE = 1.64, p = .034, 95% CI [0.23–8.15]). No significant difference was observed between PCOS − IR and healthy controls ( p = .993). In contrast, anxiety scores did not differ significantly among groups after adjustment ((F(2, 265) = 1.62, p = .199, η²p = .012), indicating a negligible effect size. Insulin resistance in women with PCOS is independently associated with elevated depressive symptoms, but not anxiety, after accounting for key demographic and metabolic confounders. These findings support the integration of routine depression screening into the clinical management of women with PCOS, particularly those with metabolic abnormalities. Future prospective studies are needed to elucidate causal pathways and evaluate whether targeted metabolic interventions can ameliorate depressive burden in this population. Not applicable.