Happy Blue Monday! Today is supposedly the most depressing day of the year

If you're feeling extra depressed returning to work this week, don't worry, Blue Monday may have something to do with it.

Blue Monday is a date that refers to the most depressing day of the year, usually on the second, third or fourth Monday of January. The concept of Blue Monday was first published in 2005 by Dr. Cliff Arnall for the holiday company Sky Travel, who said to have calculated the most depressing date by using an equationaccording to The Guardian.

The equation, which was devised to help figure out when people book holidays and holiday trends, includes factors like weather conditions, debt level, time since failing New Year's Resolutions, and low motivational levels. Using that equation, Sky Travel decreed January 24, 2005 as the first Blue Monday.

The first iteration of the equation is below.

Where Tt = travel time; D = delays; C = time spent on cultural activities; R = time spent relaxing; ZZ = time spent sleeping; St = time spent in a state of stress; P = time spent packing; Pr = time spent in preparation. The actual units for the measurements, like is travel time in hours or days, or is delays are calculated in their number or length, are undefined.

However, a 2009 press release from the Mental Health Foundation featured a new equation to determine Blue Monday, seen below.

Where W=weather, D=debt, d=monthly salary, T=time since Christmas, Q=time since failing our new year's resolutions, M=low motivational, and Na=the need to take action. The units again for this equation, such as the numerical or unit value for weather and low motivation, were again undefined.

Dr. Arnall also said, however, that he calculated the happiest day of the year from 2005-2010, which typically falls on a Friday in mid-to-late June, according to the BBC. While Blue Monday has been extensively written about since its inception in 2005, several psychologists and health professionals have called the holiday psuedoscience, according to The Guardian.

Many on social media have been offering their opinions about Blue Monday.

Do you think that today is the most depressing day of the year?