The interplay of genotype and environment in the development of fear and anxiety

Abstract

Individual differences in fear, anxiety, and the etiology of anxiety disorders develop dur­ing ontogeny. They are due to both genet­ic and environmental factors. With regard to the role of the environment, the organism is most susceptible to external influences dur­ing early development. Accordingly, stressors that impinge on the maternal organism dur­ing pregnancy evoke high levels of anxiety in the offspring later in life, as does an adverse early postnatal environment. However, anxi­ety-related circuits in the central nervous sys­tem retain their plasticity in adulthood, i.e., levels of anxiety can also be modified by ex­perience across the entire successive lifespan. Notably, the effects of external stressors on the individual’s level of anxiety are modulat­ed by genotype. Such genotype-by-environ­ment interactions are particularly well stud­ied in relation to genetic variants that modu­late the function of the serotonin transport­er. Thus, this review focuses on this candidate gene to elucidate the interplay of genotype and environment in the development of fear and anxiety.