Depression linked to brain inflammation
Years of depression can cause brain inflammation that has been linked to degenerative diseases like Alzheimer’s and Parkinson’s, a new study revealed.
About 1.5 percent of all American adults suffer from persistent depressive disorder, a long-lasting form of the mental condition.
Another 16.1 million face major depressive order, but the treatment approaches to the two are largely the same.
But an analysis of brain-changes among people whose depression lasted more than 10 years, done by the Canadian Centre for Addiction and Mental Health, suggested doctors may need to treat both depression itself and inflammation in these patients.
The average, untreated bout of depression typically lasts a few months, according to Harvard University. Everyone’s symptoms vary in type, severity, and duration. Depression may look like irritability or simply a ‘low mood.’
But the staying power of depression may make it even more difficult to diagnose, as years of the disorder come to be seen as ‘normal’ for the person suffering the symptoms.
This may be why the average age of diagnosis for persistent depressive disorder (PDD) is relatively late, at 31 years old.
Most research on the physical consequences of depression – no matter how long its episodes are – has pointed primarily on its effects on the experience of pain and the likelihood of developing other mental illnesses.
The condition is also known to affect eating habits and experiences. Some tend to overeat when they are depressed, others lose their appetites, and still others will experience upset stomachs.
A high number of physical complaints may also be, in some cases, a warning sign that someone is depressed or in the throes of another mental health issue.
Depression typically involves a shortage of serotonin, a neurochemical that nerve cells use to communicate a command for blood vessels to constrict.
This is particularly important to the way that the digestive tract functions, as well as to the experience of pain. Depression is a physical illness that could be treated with anti-inflammatory drugs, a Cambridge University professor stated in September 2017.
An overactive immune system may trigger the mental health condition by causing widespread inflammation that leads to feelings of hopelessness and unhappiness, the expert believes.
The immune system may fail to ‘switch off’ after an illness or traumatic event, he adds.
Previous research has shown people who suffer severe emotional trauma have signs of inflammation, which suggests their immune system is constantly ‘fired-up’.
Professor Ed Bullmore, head of the department of psychiatry at the University of Cambridge, said: ‘In relation to mood, beyond reasonable doubt, there is a very robust association between inflammation and depressive symptoms.
‘In experimental medicine studies if you treat a healthy individual with an inflammatory drug, like interferon, a substantial percentage of those people will become depressed,’ The Telegraph reported.
Inflammation, too, is thought to destroy serotonin, leading some scientists to suggest that inflammation itself may be the cause of depression.
But whatever the answer to the ‘chicken or egg’ question may be, researchers from the Center for Addiction and Mental Health (CAMH) found evidence that longer bouts of depression increased brain inflammation. To determine whether or not the duration of depression made a difference for its inflammatory effects, the research team, led by senior study author Dr Jeff Meyer of CAMH’s Campbell Family Mental Health Research Institute recruited three groups of 25 people.
The first group had experienced more than a decade of depression, the second had experienced less than a decade, and the third had never experienced any depression, by their own reports.
The difference between the PDD sufferers and the other two groups was dramatic. Those who had been depressed for more than 10 years had 30 percent more of a protein marker of brain-inflammation than those who had experienced depression, but for shorter amounts of time.
Unsurprisingly, their inflammation levels were also higher than the control group that had never been depressed. This was the first study to show that depression has significantly different effects depending on how long it lasts, and the different effect was a worrisome one.
‘Greater inflammation in the brain is a common response with degenerative brain diseases as they progress, such as with Alzheimer’s disease and Parkinson´s disease,’ and suggested that perhaps long-term depression should be treated with some of the same medications given to prevent these other serious diseases.