Researchers at Johns Hopkins University School of Medicine and in the United Kingdom searched electronic databases and references for longitudinal studies reporting potentially modifiable risk factors for incident dementia after mild cognitive impairment. There were 76 eligible articles comprising epidemiologic and clinical studies.
Diabetes and prediabetes increased risk of conversion from amnestic MCI to Alzheimer’s dementia and from any-type or nonamnestic MCI to all-cause dementia. But the researchers also found that the presence of neuropsychiatric symptoms predicted conversion to all-cause dementia, and depressive symptoms predicted conversion from any-type MCI to all-cause dementia in epidemiological but not clinical studies.
“A third to three-quarters of people with MCI have neuropsychiatric symptoms, most commonly depression, anxiety, apathy, and irritability,” the researchers stated. “Neuropsychiatric symptoms predicted conversion from any-type MCI to all-cause dementia. Neuropsychiatric symptoms may be etiologic for dementia, for example through neuroendocrine axis activation, or they may interact synergistically with a biological factor, such as genetic predisposition. Either of these putative relationships suggests that treating neuropsychiatric symptoms could theoretically delay dementia.”
For more on this subject see the Psychiatric News article “Dementia Risk Rises With Comorbid Diabetes, Depression.”