The causes of slow thinking are biological, psychological and social factors. Psychological factors mainly refer to a person’s ability to cope with external stimuli, how much coping ability and capacity to withstand, and what methods will be used to adapt to external stimuli and blows, and so on, which is what we call psychological quality. If a person’s ability to withstand is very strong, he or she can withstand a large blow; on the contrary, a small blow may also trigger depression. I. Biological factors: 1. Genetic aspects. If a person has a family history of depression, then the chances of this person suffering from depression are 10 times higher than the average person. In fact, so many depressed people have not suffered any big social blows at all, but because of the genetic susceptibility or strong psychological susceptibility, they are prone to depression. 2, the influence of drugs. One of the most direct factors affecting depression is the change of some compounds in the brain, such as anti-hypertensive drugs can lead to changes in brain neurotransmitters. 3.Certain endocrine diseases can also cause changes in the brain, such as hypothyroidism, which is one of the biological factors that directly lead to depression. 4, other factors, including drug addiction, alcoholism, etc. can lead to changes in some compounds in the brain, directly leading to depression. Second, social factors: Social factors are a kind of external factors, such as the study and work pressure that a person suffers in daily life, as well as family disharmony and conflicts among friends can lead to depression and even suicide. In addition, larger negative events, such as unemployment, widowhood, financial difficulties can also cause depression. 1, genetic depression and family history has a close relationship, research shows that one of the parents have depression, children have a 25% chance of getting the disease, if both parents have, the children’s prevalence rate of 50% -75%. Environmental triggers: stressful life events and feelings of loss may also trigger depression, such as widowhood, divorce, job loss and financial crisis. 3, drug factors: for some people, long-term use of certain drugs, such as high blood pressure, arthritis or Parkinson’s disease medication can also cause depression symptoms. Disease: Patients suffering from chronic diseases such as heart disease, stroke, diabetes, cancer, hyperthyroidism have a higher chance of getting depressed. 5, personality: low self-esteem, self-blame, pessimism, etc., are prone to depression. 6, diet: lack of folic acid and vitamin B12 can cause depression. 7, smoking, alcoholism, drug abuse; borrow alcohol, nicotine and drugs to soothe the mood, research shows that the use of these things can actually trigger depression.