This study aims to evaluate Premenstrual Dysphoric Disorder (PMDD) a severe disabling condition involving physical and psychological symptoms that occur a few days before menstruation and distinguish it from the cyclical worsening of existing psychiatric symptoms during the same time, known as premenstrual exacerbation. This study aims to evaluate Premenstrual Dysphoric Disorder (PMDD) a severe disabling condition involving physical and psychological symptoms that occur a few days before menstruation and distinguish it from the cyclical worsening of existing psychiatric symptoms. The aim is to evaluate Premenstrual Dysphoric Disorder (PMDD) and Premenstrual

exacerbation of psychiatric disorders. The objectives are to estimate the extent of Premenstrual Dysphoric Disorder (PMDD) in females with mental illness, estimate the magnitude of premenstrual exacerbation of existing psychiatric disorders and role as well as correlation of

socio-demographic and clinical factors in both PMDD and Premenstrual exacerbation. The study will be a prospective, observational study conducted over 18 months at GMCH, Chandigarh. A total of 500 females with mental illness will be screened using the Premenstrual Symptom Screening Tool (PSST). Those who screen positive will be followed across two visits at least 3-5 weeks apart over 12 weeks, depending on their menstrual cycle. Based on their

existing diagnosis, participants will be grouped into categories including depressive disorder, anxiety disorder, bipolar disorder, schizophrenia spectrum, obsessive compulsive disorder, substance use disorders, and other disorders. Each follow-up will include assessments using DSM-5 criteria for PMDD, C-PASS, SOFAS, and disorder-specific clinician rated scales. The findings may enhance understanding, diagnosis, and management of PMDD and premenstrual symptom worsening in Indian women with mental illness, ultimately improving their quality of life.