Psychiatric disorders do not increase risk of Alzheimer's disease
History of mood disorder, such as depression, or any psychiatric disorder were associated with a higher risk of Alzheimer's disease when psychiatric disorders that occurred at least five years before the Alzheimer's diagnosis were taken into account. However, the associations disappeared when this time window was extended to 10 years. The exponential increase in the prevalence of psychiatric disorders before the diagnosis implies that some of these psychiatric disorders might actually have been prodromal symptoms of Alzheimer's disease. This underlines the importance of proper differential diagnostics of Alzheimer's disease. Further, the findings also highlight the importance of using an appropriate time window when assessing the risk factors of neurodegenerative diseases with a long onset period. Otherwise the identified "risk factors" may actually be manifestations of the neurodegenerative disease. It should also be acknowledged that although psychiatric ...