Introduction: Nerve growth factor (NGF) has been shown to be involved in anxiety behaviour and the expression of conditioned fear in mice.
Methods: We have tested a total of 337 (age: 39.2 +/- 14.6 years) unrelated subjects of German descent (166 males; 171 females) who were carefully screened for psychiatric health. The self-ratable State-Trait Anxiety Inventory, which enables anxiety to be quantified as a comparatively stable personality trait was applied and a recently described non-synonymous NGF SNP (rs6330,c.104C > T,p.Ala35Val) was examined.
Results: In the trait-related anxiety score, a significant gender-dependent effect of the genotype was observed (F=4.580, df=2, p=0.011) with higher levels of trait anxiety in females with C/C genotype when compared to females with T/T and C/T genotypes and an opposite effect in males.
Discussion: Our findings support the hypothesis that anxiety relates to a genetic variation of NGF and that genes modulate behaviour in a gender-dependent manner. Since anxiety and attention deficit hyperactivity disorder are related to NGF, the present results may represent a common biological link for the gender-specific occurrence and comorbidity of the diseases.