In total, 450 unrelated Caucasian individuals of Armenian nationality living in Armenia (225 schizophrenic patients and 225 healthy subjects) were enrolled in this study. All patients (female/male: 71/154, mean age ± SD: 44.2 ± 9.8 years, age at the first-onset of illness: 26.4 ± 8.3 years, duration of illness: 19.5 ± 7.2 years, patients with/without family history of psychiatric disorders: 94/131) were diagnosed as paranoid schizophrenics (ICD-10 code: F20.0, DSM-IV-TR code: 295.30) by two independent experienced psychiatrists [1, 2]. The affected subjects were recruited from the clinics of the Psychiatric Medical Center of the Ministry of Health of the Republic of Armenia (MH RA). Age- and sex-matched healthy volunteers (female/male: 71/154, mean age ± SD: 42.6 ± 9.2 years) were recruited among the staff and blood donors of the Erebouni Medical Center MH RA. Exclusion criteria for healthy subjects included psychiatric illness during lifetime, any serious neurological or endocrine disorder, any medical condition or treatment known to affect the brain, or meeting DSM-IV criteria for mental retardation as determined from the non-patient version of the Structured Clinical Interview for DSM-IV-TR Axis I Disorders [23]. Exclusion criteria for all study participants included any serious medical disorder. All subjects gave their informed consents to participate in the study, which was approved by the Ethical Committee of the Institute of Molecular Biology of the National Academy of Sciences RA.