This observational cross-sectional case-control study aims to evaluate the effects of menopausal status on escitalopram metabolism in women. The study will include premenopausal and menopausal women aged 40-60 years who are currently receiving escitalopram treatment and have applied to the Psychiatry Clinic of Eskişehir Osmangazi University. The study aims to identify pharmacokinetic differences associated with hormonal status and to investigate their potential clinical implications. Findings from this research are expected to contribute to the development of evidence-based, individualized treatment strategies for women in menopausal transition.

Participants' plasma escitalopram and desmethylescitalopram levels, mental disorder severity, anthropometric measurements, bioimpedance, CYP2C19 genotype analysis, estradiol and follicle-stimulating hormone (FSH) levels, and corrected QT interval (QTc) length will be assessed. In the preliminary analysis, participants carrying the CYP2C19*1 allele will be selected from the data of 78 participants for comparative analyses. Those with the dominant allele will be selected for final analyses.

Inclusion Criteria:

• Aged 40 years or older and 60 years or younger
• Diagnosed with major depressive disorder and/or generalized anxiety disorder by an independent psychiatrist (not a member of the research team)
• Prescribed escitalopram treatment by an independent psychiatrist (not a member of the research team)
• Receiving escitalopram treatment for at least one month and on a stable dose for at least one week
• Willing to participate in the study and provide informed consent
• Additional inclusion criterion for the menopausal group: Amenorrhea for at least one year (consistent with menopause diagnosis)
• Additional inclusion criteria for the premenopausal group: Having regular menstrual cycles and being in the luteal phase (within 14 days after ovulation) of the menstrual cycle

Exclusion Criteria:

• Diagnosis of intellectual disability, dementia, psychotic disorders, schizoaffective disorder, or bipolar disorder
• Alcohol or substance use disorder
• Diagnosis of hepatic failure, renal failure, or cardiac failure
• Severe malnutrition
• Presence of an active systemic infectious or inflammatory disease
• Current use of hormone replacement therapy for menopause
• Use of oral contraceptives
• Pregnancy or breastfeeding
• Use of medications known to affect escitalopram plasma concentration
• Use of medications that affect the CYP2C19 enzyme
• Detection of alleles other than the predominant CYP2C19*1 genotype in genetic analyses

Eligibility is restricted to participants assigned female at birth, as the study focuses on premenopausal and menopausal physiological status.

Participants are women aged 40 to 60 years who have been diagnosed with major depressive disorder and/or generalized anxiety disorder and are currently receiving escitalopram treatment. All participants were recruited from the Psychiatry Clinic of Eskişehir Osmangazi University.

Participants' data will be stored anonymously in an online data repository. IPD will be shared as a study report after data completion is finished.

We plan to finish data collection in January 2028, and we plan to publish IPD in 6 months after that.

IPD will be open to the public.