Is Depression an Early Sign of Alzheimer's Disease?
In a 3-year study that followed 222 people aged 74 and older, Dr. Lars Backman and colleagues found that those who later developed Alzheimer's Disease were 50% more likely than other participants to have suffered symptoms of depression at the start of the investigation.
The study looked at two types of depression: "mood-related" symptoms such as unhappiness, guilt, and thoughts of death; and "motivated-related" symptoms which result in lack of energy and interest, and in concentration problems. The result showed that at the start of the study participants who would later develop Alzheimer's commonly had motivational-related symptoms. The researchers theorize that the symptoms may be related to changes in brain regions involved in regulating attention and energy levels.
The symptoms of depression that emerge in the study are common among the elderly and may easily be "over-looked" as early signs of Alzheimer's Disease.
Source: Neurology 1999;53:1996-2002.