There are many types of psychiatric disorders, and studies have shown that the rate of schizophrenia in the general population is 3 per 1,000, while the chance of having a blood relative with schizophrenia is higher than that of the general population. According to current research, the prevalence of schizophrenia in siblings is 7-15%, and if one parent has the disorder, the prevalence increases to 16%, and if both parents have the disorder, the prevalence in children is 40%-68%. As for bipolar disorder, the prevalence rate is about 0.4% for the general population, 26.3% for dizygotic twins, and 95.7% for identical twins. Therefore, we must consider the influence of genetics. Although genetics plays an important role in the cause of psychiatric disorders, it is not an absolute factor, i.e., children with genetic influences do not always develop the disorder, and we cannot ignore the factors of the later life environment.