Older bipolar patients often have decreased levels of the stress hormone cortisol, which may lead to depression, low quality of life, obesity, metabolic syndrome, and dyslipidemia (an abnormal amount of fat/cholesterol in the blood), according to new findings by doctoral student Martin Maripuu at Umeå University in Sweden.
These discoveries may lead to better treatment strategies for depression and bipolar disorder.
Maripuu has been studying the link between hypocortisolism (low cortisol levels) and poor psychiatric and somatic health in patients with recurrent depression or bipolar disorder. He found that poor physical health in the form of obesity, metabolic syndrome, and dyslipidemia was considerably more common in patients with low cortisol levels compared to those with normal or high cortisol levels.
Bipolar patients with either high or low cortisol levels were almost twice as likely to be depressed compared to those with normal stress regulation. Low quality of life was between four and six times more common in groups with low or high activity in the stress regulation system.
In people with recurrent depression, a link was also found between low cortisol levels and short telomeres.
Telomeres are repetitive nucleotide sequences that cap the end of each strand of DNA and protect our chromosomes, like the plastic tips at the end of shoelaces. Shorter telomeres are considered an indication of premature aging and high accumulation of stress.
“High cortisol levels have previously been shown to be associated with poor health in people with depressions or bipolar disorder. What’s interesting about our results is that also low cortisol levels were associated with a considerable increase in negative health consequences,” said Maripuu.
Approximately eight percent of the population suffers from recurring depression, and about one percent suffers from bipolar disorder, an illness characterized by recurring depression and hypomanic/manic episodes.
In the short term, stress contributes to increased activity in the hormone system regulating the secretion of cortisol. In fact, many patients with depression experience hyperactivity in the hormone system, causing very high levels of cortisol. However, patients with high levels of stress over a long period of time have been found to suffer from hypocortisolism (low cortisol).
It is possible, therefore, that recurring episodes of depression and/or mania with a high accumulation of stress will eventually lead to an exhaustion of the hormone system.
Support for this hypothesis was seen in the group of bipolar patients in which older patients exhibited lower cortisol levels, especially among patients that throughout life had been without prophylactic mood stabilizing treatment.
No increase was found however, in cases of hypocortisolism among bipolar patients who had been treated with the mood stabilizer lithium during a large part of their lives. Therefore, lithium treatment in bipolar disorder may help prevent the development of hypocortisolism, Maripuu said.
Source: Umeå University