Chronic Toxoplasma gondii (T. gondii) infection is a widespread condition that can negatively affect brain function and is considered a risk factor for various psychiatric conditions, including depression and schizophrenia. This prospective observational study aims to investigate the expression levels of specific circulating microRNAs (miRNAs) in women diagnosed with schizophrenia, major depressive disorder, or bipolar disorder who also have chronic toxoplasmosis. By comparing these levels to patients without the infection, the study seeks to determine if these miRNAs can serve as biological markers to help differentiate between specific psychological disorders and identify the impact of chronic toxoplasmosis on mental health.

Inclusion Criteria:

• Confirmed psychiatric diagnosis of Schizophrenia (SCZ), Major Depressive Disorder (MDD), or Bipolar Disorder (BD) according to DSM-5 criteria.
• Seronegative for T. gondii IgM (to ensure infection is not in the acute phase).
• Signed informed consent.

Exclusion Criteria:

• Psychiatric disorders other than Schizophrenia, MDD, and Bipolar Disorder.

Seropositive for T. gondii IgM (indicating acute infection).

Refusal to participate.

The study population consists of adult women (aged 18 years and older) who have been clinically diagnosed with Schizophrenia, Major Depressive Disorder, or Bipolar Disorder according to DSM-5 criteria. These patients are recruited from the psychiatric departments of Benha and Tanta Universities. Within this group, the population is divided into two cohorts: those with chronic toxoplasmosis (confirmed by the presence of anti-Toxoplasma IgG antibodies) and those without the infection. To ensure a specific focus on chronic cases, the study excludes patients with acute toxoplasmosis (IgM positive) or other unrelated psychiatric conditions. No healthy volunteers are included, as the research specifically aims to differentiate biomarkers among patients already experiencing psychological disturbances.