Depression affects an estimated 5% of the world population, according to the WHO, and is the leading cause of disability for both male and female workers (though it affects women 50% more than men). Despite its ubiquity, the disease is complex to understand, and to treat. The latest family of antidepressants was developed in the 1980s and drugs today, while improved, haven’t changed substantially since then.
And there are a variety of drugs to choose from (at least 18 medications in several different brands and preparations), which can make it difficult for doctors to select the optimal treatment for a patient.
Gregor Hasler, a professor of Psychiatry at the University of Bern, told Quartz that most therapies for depression are decided on by trial-and-error: in about 30% patients, the first drug prescribed is effective, but for the remaining 70% it can take anywhere from weeks to years to find a successful therapy.
A new study, which Hasler co-authored with his colleague Philipp Homan and published in Nature’s Journal of Translational Psychiatry, may shed light on the nature of two of the most common types of depression and could help dramatically improve the accuracy of drug prescription. These two forms of depression are linked to two chemical imbalances: serotonin deficiency and lack of noradrenaline. Being able to distinguish between the two could help tremendously in predicting a patient’s response to different types of antidepressant medications. Thus far, no measurable markers had been found to indicate what type of depression a patient might be suffering from, but Hasler and Homan’s research was able to differentiate the symptoms of the two different types of depression.
“More psychological symptoms are related to serotonin,” Hasler told Quartz, while “more somatic symptoms—short breath, sweating, feeling of chocking are all bought by [lack of noradrenaline].”
Reducing serotonin in the study subjects, says Hasler, led to what is more commonly recognized as a “depressive mood,” nicknamed a lack of “New-York-type happiness” (positive energy). On the other hand, a reduction of noradrenaline did not cause sadness, but rather a lack of motivation and concentration difficulties, or lack of “Eastern-type” happiness (calmness). This is the first time that different symptoms were directly linked to one deficiency or the other, which in turn could predict the response to treatments and provide patients with greater relief.
Correction: A previous version of the story referred to the study in the Journal of Translational Psychology.