Depression has a certain hereditary tendency. Studies involving large samples have found that if first-degree relatives of patients with depression have the disorder, the incidence of the disease in their offspring is significantly higher than in the general population. Additionally, studies on twins have shown that the concordance rate of depression in monozygotic twins is significantly higher than in dizygotic twins. Research in genetic studies has revealed that depression is a polygenic disorder. Therefore, it is possible for offspring of parents with depression not to inherit the disease. The onset of depression is often influenced by genetic factors, biochemical factors, and various social and psychological factors. Thus, the genetic probability of developing depression is generally higher than in the general population.