Depression: Early warning of dementia?

Persistent sadness might be more than just a mood problem—it could be a warning sign of memory impairment.

You can't sleep. You feel irritable and restless. Foods you once loved look unappetizing. These are signs that you may be depressed, but they might also warn that you're at greater risk for dementia.

A study published in the May issue of the Archives of General Psychiatry found that people who became depressed late in life had a 70% increased risk of dementia, and those who'd been depressed since middle age were at 80% greater risk.

Researchers have long known that depression and dementia go hand in hand. Yet they've debated over whether the two conditions simply share common causes, or whether depression is an early sign of dementia. Both theories appear to be true. The authors of the study also say depression late in life may indicate that changes have occurred in the brain that can make us more prone to developing dementia.

Often, older adults miss the symptoms of depression or misattribute them to the inevitable consequences of aging. "I think older individuals are more in denial about having depressive illness," says Dr. M. Cornelia Cremens, assistant professor of psychiatry at Harvard Medical School and a geriatric psychiatrist in the senior health practice at Massachusetts General Hospital. "They'll say, ‘Well, I'm 83 years old—who wouldn't be depressed?'" Ignoring sadness or dismissing it as a normal side effect of aging could allow potentially treatable memory issues to progress unchecked.

Depression common with age

The link between depression and dementia is even more significant considering that depression becomes more common with age. All of the following may put you at risk for depression as you get older:

• the death of a spouse, friends, or family members

• having to move out of your home and into an assisted living facility

• side effects of medicines you're taking for health conditions.

You're also more likely to develop illnesses such as diabetes, heart disease, and cancer as you get older. These conditions can increase your risk for depression, and vice versa. Depression can make a chronic illness worse, says Dr. Cremens.

What to do if you're blue

If you have any signs of depression (see sidebar), the first step should be to see your doctor or a psychiatrist. Yet many people avoid getting diagnosed because of the stigma depression still holds for older adults. "Older people still have the idea that, ‘I'm not crazy. I don't want people to think I'm crazy,'" Dr. Cremens says.

"If somebody appears to have the beginnings of dementia and they are depressed, it's very important to treat their depression, and to treat it as aggressively as possible," she adds.

The treatment for depression at any age usually involves a combination of antidepressant medicines, talk therapy, and cognitive behavioral therapy (which will teach you skills you need to cope with your depression).

"I think older women who are depressed should also be evaluated for dementia," Dr. Cremens says. Screening tests such as the Mini-Mental State Exam (MSE) and the Montreal Cognitive Assessment (MoCA) are short questionnaires your doctor can use to pick up on cognitive impairment early.

Although there isn't any real method to prevent dementia, you may be able to reduce your risk by not only treating depression, but by also following healthy lifestyle habits such as exercising, eating a healthy diet, and keeping your mind active with social outings and games. Knowing you're at high risk for dementia can also help you and your family prepare for it, so it won't be as much of a shock down the road.

Get treated, and keep getting monitored by your doctors until your depression is under control. If you're feeling so low that you're considering ending your own life, call 911, your health care provider, or the National Suicide Prevention Hotline (800-273-8255) immediately.