Depression is very common among individuals with Alzheimer's disease. In fact, estimates suggest that as many as 40 percent of people with Alzheimer's suffer from significant depression, according to the Alzheimer's Association.

A new study by researchers from the University of Eastern Finland looks at how antidepressants are actually used quite frequently before a definite diagnosis.

Alzheimer's remains the most common form of dementia, an irreversible, progressive brain disorder that slowly destroys memory and thinking skills, along with the ability to eventually carry out everyday tasks. Onset of Alzheimer's typically appears in mid-'60s and is the result of abnormal clumps, known as amyloid plaques, and tangled bundles of fibers, called tau tangles or neurofibrillary.

Onset of the health issue may come with many symptoms, including a gradual decline in memory, thinking and reasoning skills. In fact, health officials note 10 warning signs and symptoms in which caregivers or the individual should notify a doctor if experiencing, including the following: memory loss that disrupts daily life, challenges in planning or solving problems, difficulties completing familiar tasks at home or work, confusion with time and place, trouble understanding visual images and spatial relationships, problems with writing or speaking, misplacing things and losing the ability to retrace steps, decreased or poor judgment, withdrawal from work or social activities and changes in mood and personality.

Depression can also hide in the mix of these symptoms but more subtly. For instance, initial signs of depression in Alzheimer's might include loss of interest in activities or hobbies, apathy, social withdrawal, isolation, trouble concentrating and impaired thinking. In addition, some individuals may have difficulties articulating sadness, hopelessness, guilt and other feelings typically linked to depression. 

During this recent study, researchers investigated antidepressant use in the Finnish nationwide MEDALZ study of about 62,000 Finnish persons with Alzheimer's disease who were diagnosed between 2005 and 2011, from 9 years before until 4 years after a diagnosis of Alzheimer's disease.

Throughout a 13-year-follow-up period, there was a difference in antidepressant initiations. About 42 percent of persons with Alzheimer's disease were on antidepressants while about 22 percent of persons not diagnosed with Alzheimer's were on antidepressants. Researchers also noted that the most commonly used antidepressant group was selective serotonin reuptake inhibitors (SSRIs). 

The study results also showed that initiation of antidepressant use was most common during the six months after a diagnosis of Alzheimer's when compared to people without Alzheimer's disease, even 4 years after the diagnosis.

The study is published today in the International Journal of Geriatric Psychiatry.