Does depression cause dementia? While no direct causal relationship has been proven, studies show that depression does in fact contribute to the onset of dementia.
Many people suffer from various degrees of depression and as we age, depression becomes more and more prevalent. Our ability to do things that we used to take for granted diminishes, our memory naturally declines as we age and our physical abilities also decline through aging. These factors often take their toll on our self-esteem and contribute to a state of depression.
Depression can also be caused by a physiological change in the brain that makes it more difficult to be interested in the things that used to give a sense of satisfaction.
According to the latest "Diagnostic and Statistical Manual of Mental Disorders (DSM-5)", a person is said to have depression if, over at least a two week period, they suffer from a depressed mood or a loss of interest or pleasure in activities as well as any three of
- Significant weight loss when not dieting or weight gain.
- Inability to sleep or oversleeping nearly every day.
- Psychomotor agitation or retardation nearly every day.
- Fatigue or loss of energy nearly every day.
- Feelings of worthlessness or excessive or inappropriate guilt (which may be delusional) nearly every day.
- Diminished ability to think or concentrate, or indecisiveness, nearly every day.
- Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide.
Dealing with depression early, even if it is mild and not debilitating, is important because studies have shown that depression is a risk factor for dementia, particularly Alzheimer's disease and vascular dementia.
One report published in the British Journal of Psychiatry analyzed 23 studies that followed almost 50,000 older adults (over 50 years of age) for a median of 5 years. They found that those with depression were more than twice as likely to develop vascular dementia and 65% more likely to develop Alzheimer's disease than people of a similar age who did not have depression.
While the reasons aren't known absolutely, research shows possible causes include:
- people with depression have higher levels of cortisol which causes an adverse effect on the hippocampus which is a part of the brain responsible for learning and short-term memory.
- research has found that depression contributes to chronic inflammation that damages blood vessels and impedes blood flow in the brain resulting in a deterioration of neural networks.
So what can we do about it?
Debilitating depression isn't something that you can work through on your own. When people feel truly depressed they can't see the light at the end of the tunnel anymore. A person feeling this way needs to get professional help. On the other hand, there are techniques to help deal with less severe depression before it becomes more serious.
- Focus on doing little things that build your self-esteem, things that are within your control.
- Build on little successes and small accomplishments.
- Don't take on big projects that require time to come to fruition as they may cause frustration in the short term and make the condition worse.
- Make the effort to socialize.
Feeling depressed makes us avoid making the effort to get out there and socialize. The isolation that results from spending too much time alone leads to loneliness and other negative emotions that make the feeling of depression worse. Having social interaction with others is important to our well-being.
While conclusive proof of the causal connection between depression and dementia is still lacking, there are many, many studies that have convincingly linked untreated depression in older adults to cognitive decline. The good news is that once the depression is treated, the changes in cognition reverse if it is treated early and effectively. As we say in our training - "Treat the treatable and reverse the reversible". Depression is often treatable, and the negative effects reversible.