title: The relationship between the Met allele of the BDNF Val66Met polymorphism and impairments in decision making under ambiguity in patients with obsessive-compulsive disorder.
abstract: Brain-derived neurotrophic factor (BDNF) gene has an important link to neurotransmitter systems, including serotonin, and seems to play a major role in emotional decision making. Impairment of decision making is an important feature of psychiatric disorders such as obsessive-compulsive disorder (OCD). We explore the link between decision making and the BDNF Val66Met polymorphism, which results in a reduction of BDNF activity, in a sample of Caucasian OCD patients. We used the Iowa Gambling Task (IGT) to measure decision making in 122 OCD patients. All patients were assessed using the Yale-Brown Obsessive-Compulsive Scale, the Beck Depression Inventory, the Beck Anxiety Inventory and the Raven Progressive Matrices. Patients also performed the Continuous Performance Task (CPT-II) and the Trail Making Test (TMT). We grouped Met-allele carriers because these act in a dominant way. Met-allele carries exhibited low performance on both halves of the IGT (first half -F = -2.51, df = 120, P = 0.01; second half -F = -2.32, df = 120, P = 0.02). However, logistic regression analyses showed that the influence of the Met allele seemed to be restricted to the first half of the IGT [first half -β = 0.55, df = 1, P < 0.01, odds ratio (OR) = 5.62; second half -β = 0.32, df = 1, P = 0.15, OR = 2.30]. No differences were observed in tests used to evaluate executive functions associated with the dorsolateral prefrontal cortices (TMT and CPT-II, df = 120, P > 0.05 for both). Met-allele impairment may only be related to decisions made under ambiguous conditions. The null results involving TMT and CPT-II are possibly related to the dysfunction of the orbitofrontal cortices that is associated with OCD.
authors.affiliation: Medicine Molecular Program Department of Psychology Neuroscience Program Department of Mental Health, Faculty of Medicine, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Brazil. fil_bh@yahoo.com.br
authors.forename: F F
authors.initials: FF
authors.lastname: da Rocha
authors.forename: L
authors.initials: L
authors.lastname: Malloy-Diniz
authors.forename: N V
authors.initials: NV
authors.lastname: Lage
authors.forename: H
authors.initials: H
authors.lastname: Corrêa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D003657:Decision Making / Q000502:physiology*; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009771:Obsessive-Compulsive Disorder / Q000235:genetics* / Q000523:psychology; D020641:Polymorphism, Single Nucleotide; D011569:Psychiatric Status Rating Scales
chemical_list: D019208:Brain-Derived Neurotrophic Factor