title: The serotonin transporter gene 5-HTTLPR polymorphism is associated with affective psychoses but not with schizophrenia: A large-scale study in the Russian population.
abstract: Affective syndrome is thought to be a key feature that differentiates schizophrenia from schizoaffective disorder (SA) and bipolar disorder with psychotic features (BDP). However genetic underpinnings of these differences remain unresolved.
  
  
  
  We compared clinical variables of affective psychoses (SA, BDP and schizophrenia with affective symptoms (AFF SCZ)) and schizophrenia without affective symptoms (non-AFF SCZ) and searched for a genetic variant that may differentiate affective psychosis from non-AFF SCZ.
  
  
  
  A total of 2677 subjects, including 831 patients with affective psychosis, 785 patients with non-AFF SCZ and 1061 healthy controls, were used. Clinical symptoms were assessed with the PANSS. The sample was genotyped for 5-HTTLPR polymorphism of the serotonin transporter gene.
  
  
  
  The diagnostic groups differed significantly on demographic and clinical variables. The percentage of men was higher, the current age and age at illness onset were lower in non-AFF SCZ and SA compared to AFF SCZ and BDP. The severity of positive and negative symptoms decreased significantly from group to group in the following manner: non-AFF SCZ>AFF SCZ>SA>BDP. There was the association between 5-HTTLPR polymorphism and affective psychosis (p=0.01). The frequency of the SS genotype was higher in the affective psychosis group compared to non-AFF SCZ and controls. No differences in the genotype distribution were identified between the non-AFF SCZ group and controls.
  
  
  
  Difficulties in the differentiation between non-AFF SCZ and AFF SCZ or SA and between AFF SCZ and SA due to uncertain diagnostic boundaries between these conditions.
  
  
  
  SA is intermediate between non-AFF SCZ and BDP in the severity of positive and negative symptoms. The first episode patients, carriers of the SS genotype have a higher risk of developing affective psychosis than non-AFF SCZ. This finding carries implications for the prognosis of psychosis outcomes in the first-episode patients.
authors.affiliation: Mental Health Research Center, Moscow, Russia.
authors.forename: Vera
authors.initials: V
authors.lastname: Golimbet
authors.affiliation: Mental Health Research Center, Moscow, Russia.
authors.forename: Galina
authors.initials: G
authors.lastname: Korovaitseva
authors.affiliation: Mental Health Research Center, Moscow, Russia.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Lezheiko
authors.affiliation: Mental Health Research Center, Moscow, Russia.
authors.forename: L I
authors.initials: LI
authors.lastname: Abramova
authors.affiliation: Mental Health Research Center, Moscow, Russia.
authors.forename: V G
authors.initials: VG
authors.lastname: Kaleda
mesh_terms: D000328:Adult; D000341:Affective Disorders, Psychotic / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011618:Psychotic Disorders / Q000235:genetics; D012426:Russia; D012559:Schizophrenia / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins
keywords: Affective syndrome serotonin transporter gene; Bipolar disorder; Outcome; Schizoaffective disorder; Schizophrenia