Heritability Estimates

Heritability Estimates tell us what proportion of variation in a given behavior or a disorder is due to genes versus the environment. These estimates range from 0.0 to 1.0, with 0.0 indicating that genetics are not a contributing factor at all and 1.0 indicating that genetics are the only factor.

The heritability estimate for major depression is .50, which means that half of the variation seen in major depression across a population is due to genes (biologically inherited) and half is due to the environment (school, work, home life, etc.). In other words, genes and environment contribute equally to this disorder.

Related: Heritability