Alzheimer's or depression: Could it be both?

Early Alzheimer's and depression share many symptoms, so it can be difficult even for doctors to distinguish between the two disorders. And, not surprisingly, many people with Alzheimer's also are depressed.

In fact, new studies have linked depression and Alzheimer's. People with a history of clinical depression also have an increased risk of eventually developing Alzheimer's.

Similar symptoms

In addition to sadness, depression causes loss of interest in once-enjoyable activities and hobbies. This also happens in Alzheimer's. Social and emotional withdrawal is common in both conditions, as are impaired memory and concentration.

As Alzheimer's disease progresses, communication skills break down. As a result, depression becomes even harder to recognize. Many people with moderate to severe Alzheimer's disease lack both the insight and the vocabulary to express how they feel or even to accurately answer direct questions about their symptoms.

"For example," says Glenn Smith, Ph.D., a psychologist at Mayo Clinic, Rochester, Minn., "if you were to ask a person with Alzheimer's if he or she rested well last night, the response might be 'I'm OK,' even if that person had not slept at all."

An important distinction

Considering these difficulties, it's easy to see why some people with depression have been mistakenly diagnosed with Alzheimer's, and vice versa. The distinction is important, though. Alzheimer's has no cure, but people with depression — whether it accompanies Alzheimer's or not — usually respond quite well to treatment.

In fact, depression treatment dramatically improves the quality of life for people who have both Alzheimer's and depression. A thorough physical exam and psychological evaluation can help detect depression in people who have Alzheimer's disease.

Signposts for depression

To detect depression in people with Alzheimer's disease, doctors must rely more heavily on nonverbal cues than on self-reported symptoms. If a person with Alzheimer's displays one of the first two symptoms in this list, along with at least two of the others, he or she may be depressed.

• Significantly depressed mood — sad, hopeless, discouraged, tearful
• Reduced pleasure in or response to social contacts and usual activities
• Social isolation or withdrawal
• Eating too much or too little
• Sleeping too much or too little
• Agitation or lethargy
• Irritability
• Fatigue or loss of energy
• Feelings of worthlessness, hopelessness or inappropriate guilt
• Recurrent thoughts of death or suicide

Men and women with Alzheimer's become depressed with equal frequency. This differs from the general population, in which women are more likely to experience depression than are men. People with Alzheimer's may also experience depression differently than do people without Alzheimer's. For example:

• Symptoms may be less severe.
• Episodes of depression may not last as long or recur as often.
• Talk of suicide and attempted suicide is usually less common.

Types of treatment

Support groups and professional counseling may help depressed people in the early stages of Alzheimer's disease, before their communication skills deteriorate. Increased mental stimulation and physical activity also may help alleviate depression.

Antidepressant medications are safe and effective, with minimal side effects. Physicians often try various drugs and dosages to see what works best for each individual. Results usually appear within just a few weeks.

Selective serotonin reuptake inhibitors (SSRIs) are the most common type of antidepressants used for people who also have Alzheimer's. These include citalopram (Celexa), sertraline (Zoloft), paroxetine (Paxil) and fluoxetine (Prozac).

People with Alzheimer's may also respond to antidepressants that inhibit the reuptake of brain chemicals other than serotonin. These include venlafaxine (Effexor), mirtazapine (Remeron) and bupropion (Wellbutrin).

Tricyclic antidepressants, such as nortriptyline (Pamelor) and desipramine (Norpramine), are no longer used as first-choice treatments. However, they may be prescribed if other medications aren't effective.

Some patients with depression and dementia may not respond to medication. Many of these patients benefit from electroconvulsive therapy (ECT).

Is depression a risk factor for Alzheimer's?

A recent study suggests depression in older people may precede the development of Alzheimer's. This seven-year study tracked both depression and Alzheimer's symptoms in hundreds of people age 65 or older.

No participants had Alzheimer's symptoms at the beginning of the study. But those who reported the most depressive symptoms on a yearly questionnaire they completed during the study were more likely to eventually develop Alzheimer's. In fact, this tendency grew stronger with each additional depressive symptom reported.

Further research is needed to explore this possible link and determine whether treating the depression can reduce the risk for subsequent Alzheimer's. For now, recognizing and treating depression in older people, regardless of whether they have Alzheimer's disease, remains the best bet.