A NEW TYPE OF DEPRESSION THAT CANNOT BE TREATED WITH ANTIDEPRESSANTS

Scientists have identified a new type of depression that cannot be treated with antidepressants.
One of the factors contributing to the development of such depression may be the modern lifestyle.
Scientists have recently identified a new type of depression that is associated with a disruption of the human biological clock.

According to newscientist.com , studies have shown that this “circadian depression” accounts for more than a quarter of all cases. It responds poorly to standard antidepressants but can be alleviated by taking melatonin or making behavioral changes, such as getting outside for morning sun exposure.

Scientists from the University of Sydney in Australia asked more than 10,000 people in Australia with severe, recurrent depression to complete questionnaires on their sleep patterns and other characteristics, such as seasonal changes in symptoms. Participants also provided saliva samples for DNA analysis.
As a result, 23 percent of these participants were diagnosed with circadian depression. This meant they exhibited at least three of six signs of circadian rhythm disruption: being an “evening type,” falling asleep later than most people, experiencing extreme fatigue upon waking regardless of sleep duration, increased sleepiness during depressive episodes, going to bed late on non-workdays, and experiencing significant seasonal changes in mood, energy, sleep, and appetite.

“It’s not just about the quantity or volume of sleep, but the rhythm and regularity of sleep,” says research team member Emiliana Tonini.

Moreover, people with circadian depression tended to experience more severe symptoms than those with noncircadian depression, including more frequent suicidal ideation. Symptoms also developed at an earlier age—the average age of symptom onset was 18 years in the circadian depression group and 23 years in the noncircadian depression group.
One factor contributing to depression may be our modern lifestyle, says research team member Ian Hickey. Our biological clocks need to be reset every morning through light exposure to maintain stable 24-hour rhythms, and they can be destabilized by exposure to artificial light at times when we would historically be in darkness, he says.

Moreover, it was found that participants diagnosed with circadian depression reported lower efficacy and more side effects when taking common antidepressants. This may be due to the fact that these medications target a form of depression associated with the neurotransmitter serotonin.

How to cure circadian depression
Researchers are planning to launch a clinical trial to determine whether a synthetic form of the hormone melatonin, which regulates sleep-wake cycles, could be more effective in treating circadian depression. The antidepressant agomelatine, which mimics the effects of melatonin in the brain, has previously been shown to improve sleep and reduce overall depression.

After dark, Hickey recommends avoiding large meals, exercise, and exposure to bright light. He says adjusting your body clock not only helps with depression but can also help reduce inflammation and maintain a healthy weight.
The psychiatrist previously explained that signs of depression can include not only sadness and anxiety, but also changes in appetite, sleep problems, irritability, or loss of interest in favorite activities.