For around fifteen years, the expression “Blue Monday” has reappeared in January on social networks and in the media… The “most depressing Monday of the year” falls this year on January 15, in a particularly morose.

Problem: this concept, allegedly based on the scholarly calculations of a psychologist, only exists in the minds of marketing experts. Deciphering this “false” with commercial aims, far removed from real psychological problems.

Where did this invention come from?

Blue Monday (which is inspired by the English expression to feel blue, “to be depressed”) would irrefutably designate the third Monday in January as the most depressing day of the year… according to an alleged scientific study published in 2005 , which is based on the following equation:

Why is it wrong

“These kinds of calculations threaten the public’s understanding of science and psychology. It is also disrespectful to those who suffer from real depression, because it implies that it is a temporary and minor experience, which everyone suffers from,” recalls neuroscience researcher Dean Burnett in the Guardian.

Beyond the moral problem posed by the propagation of pseudoscience, Blue Monday, which was only a commercial operation, can also encourage a worrying phenomenon of compulsive spending. According to a study conducted by a British institute, the Money and Mental Health Institute, out of 5,500 people suffering from mental disorders, nine out of ten people spend more money when they are not feeling well. Purchases trigger a feeling of guilt, which can give rise to other purchases to “feel better”… triggering a vicious circle well described by many psychologists.

[An earlier version of this article was published in January 2019.]