We don’t expect that depression will be more frequent or more severe with age. In fact, we generally expect the opposite pattern. The best evidence about this question comes from large community surveys. Those surveys identify everyone with mood disorders―whether or not those people are receiving treatment. Those surveys tell us two important things about how mood disorders change with age. First, we see that the percentage of people with active mood symptoms goes down with age. Symptoms of mania tend to be most common in young adulthood and then gradually decline. Symptoms of depression tend to be most common in mid-life and then gradually decline. But both are less common overall after age 50 or 60. Second, surveys that re-examine the same people many years later show that recovery is common―even among people who experienced severe symptoms early in life.
There certainly are some studies saying that mood disorders can have a progressive or malignant path―with depression and mania becoming more frequent and more severe over time. But those studies have selected people who need the most intensive treatment. So it is not surprising that the picture from those studies is pessimistic. If we consider everyone affected by mood disorders, the picture is more positive.
It’s also important to remember that some kinds of depression first appear later in life. Depression can be caused by chronic medical illness, especially neurological illnesses like strokes, Parkinson’s disease, or multiple sclerosis. Still, the overall rate of clinical depression is lower in older people.
We can think of different reasons why symptoms of mood disorder generally decline with age. This could be due to changes in brain biology that help to make mood more stable. It’s also likely that people with mood disorders do learn more how to manage mood symptoms and prevent more severe episodes. Older often is wiser!
Of course, averages don’t apply to every individual. Some people with bipolar disorder do experience more severe symptoms―either depression or mania―as they age. But the average is more hopeful.