Mild mental retardation means that the patient’s IQ is lower than normal. If the IQ test scale is used to indicate that the general IQ is around 70, it can be considered as mild mental retardation. Its causes are categorized into the following aspects: First, for children: there may be low intelligence caused by genetic disease, or low intelligence caused by brain damage during the birth process. Secondly, for adults: 1. When there is mild mental retardation, you need to consider whether there is any traumatic brain injury, which is a more common cause nowadays. Because there are more car accidents, head injuries can cause mild mental retardation. 2, is that the elderly can be due to cerebrovascular disease or other factors, resulting in mental retardation of the brain.