Biological factors: ①Neurobiochemistry, psychopharmacological studies and neurotransmitter metabolism studies confirm the presence of abnormal central neurotransmitter metabolism and corresponding receptor functional alterations in patients. (DA) may be associated with manic episodes; dopamine (DA) has abnormal functional activity; gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter of the central nervous system and may have abnormal functional activity, because antiepileptic drugs acting on this neurotransmitter can be used as mood stabilizers and effective treatment for mania and bipolar disorder. (2) Dysregulation of second messenger balance, which is an indispensable mediator between extracellular information and intracellular effects; (3) Dysregulation of neuroendocrine function, mainly of hypothalamic D pituitary-adrenocortical axis and hypothalamic D pituitary D thyroid axis. Genetic factors: Family lineage survey found that the prevalence of bipolar disorder in the first-degree relatives of individuals with bipolar I disorder preexisting evidence is twice as high as that in the first-degree relatives of normal individuals, and the closer the blood relationship, the higher the prevalence. In terms of molecular genetics, many scholars have explored marker genes that may be associated with bipolar disorder, but no exact and reproducible results are available, and the susceptibility genes for bipolar disorder need further study. At present, the tendency about the mode of inheritance of bipolar disorder is polygenic. Psychosocial factors: adverse life events and environmental stressful events can trigger the onset of affective disorders, such as unemployment, loss of love, poor family relationships, and long periods of highly stressful living conditions. Genetic factors in the development of affective disorders may lead to a susceptible quality, and people with this susceptible quality develop the disorder when promoted by certain environmental factors.