Factors that directly or indirectly cause damage to the cerebral cortex can cause cognitive impairment. Common causes include a number of chronic diseases such as Alzheimer’s disease, cerebrovascular disease, Parkinson’s disease, diabetes and hypertension; and psychiatric and psychological abnormalities such as depression, melancholy and agitation. Chronic brain injury, such as lentiviral infection of brain tissue, ischaemic brain injury, traumatic brain injury, brain ageing, etc. Influence of social factors, most commonly educational attainment. In addition, alcohol and drug abuse can also lead to temporary cognitive impairment.