The causes of mild cognitive impairment can include the side effects of medications, alcohol, sleep deprivation, head injuries, and some neurological/psychiatric disorders. But mild cognitive impairment is also found in the early stages of neurodegenerative diseases like forms of dementia, including Alzheimer’s disease.[1][2][3]
The exact cause of mild cognitive impairment associated with dementia and Alzheimer’s disease is unknown, but the risk factors include advanced age and diabetes.[2][4] A family history of dementia or Alzheimer's disease also increases risk, suggesting that inherited genetic traits play a role. For example, people with the APOE-ε4 variant in the gene coding apolipoprotein E have a greater risk of developing mild cognitive impairment.[5]