BDNF Val66Met polymorphism is associated with negative symptoms in early-onset schizophrenia spectrum and other psychotic disorders

Abstract

Background and ObjectivesTo investigate the clinical characteristics of adolescents with early-onset full psychotic disorders either with Brain-derived neurotrophic factor (BDNF) Val66Met (rs6265) or DRD2/ANKK1 Taq1A (rs1800497) polymorphisms. Method101 cases with early-onset schizophrenia (EOS) or other psychotic spectrum disorders (SSD) and 150 healthy controls were included in the current study. Using the Positive and Negative Symptom Scale (PANSS), patient subgroups were compared for their psychotic symptoms, age-onset, duration of untreated illness, and family history of psychiatric disorders. The real-time polymerase chain reaction (RT-PCR) was implemented for genotyping procedures. ResultsStudy groups and patient subgroups were similar regarding their sociodemographic characteristics (16.4 ± 2.6 years, 62.2% male for all participants). Results did not reveal any difference between patients and healthy controls for DRD2/ANKK1 Taq1A and BDNF Val66Met genotypes. Patients with A1A2 (Gly/Lys) allele reported higher rates of substance use compared to A2A2 (Glu/Glu) counterparts. Other clinical variables were found similar. EOS/SSD group with Val66Met heterozygote allele revealed lower levels of negative symptoms than Val/Val homozygotes. Conversely, the age onset of full psychotic disorder, total positive symptom score, and total general psychopathology score of PANSS were found comparable between Val/Met and Val/Val groups. In the logistic regression model, Glu/Lys genotypes remained significant for the presence of substance use. ConclusionThe interaction between substance use and the DRD2 gene should be investigated for the development of early-onset psychotic disorders. BDNF Val66Met polymorphism also could be a disease-modifying factor for the presence of negative symptoms.