Each year at the beginning and end of the season, games mostly go according to form. The good teams beat the bad teams, with decent squads fighting it out in between. However, wacky things always happen in December and January, with uncharacteristic upsets seeming unusually common. In only the past week and a half, the Magic lost to the Pacers and Bulls, the Cavs dropped one at home to the Bobcats, the Celtics were beaten by both the Clippers and Warriors, the Hawks lost at home to the Knicks and got blown out by the Heat, and the Lakers almost fell to the Kings (twice).

Now, there are several reasons as to why this occurs. The NBA season is so long that even though the players are professionals, it’s hard for them to bring maximum effort every night. For the league’s best teams, it’s difficult to get fired up emotionally for every game, especially if you consistently blow out your opponents. For example, when Pau Gasol returned from injury the Lakers won 16 of 17 games by around 13 points per contest. Then they had several tough battles against poor teams. Not to mention that the top franchises always receive their opponents’ utmost, as everyone wants to knock down the champs.

Furthermore, teams have to account for nagging injuries and poor shooting nights. Coaches may start to rest star players to keep them fresh for the playoffs. These are some of the valid explanations for mid-season slip-ups.

But how about another theory that may never have been posited before? How about the SAD theory? I know this sounds a bit goofy, but SAD is actually an acronym standing for Seasonal Affective Disorder, a medically recognized mood disorder. It is caused by, among other things, a decrease in melatonin due to less sunlight during the winter months, and it is characterized by depressive symptoms.

For those of you who think SAD is a bunch of BS, I can attest to its legitimacy. I experienced it myself during the first real week of winter my freshman year at Columbia. Growing up on the West Coast, I was shocked by how brutal it could be, and I spent a good week not leaving my dorm, not changing out of my pajamas, and not eating anything but Chinese delivery. (Thank god for lunch specials.) People who know me know that I am almost always extremely happy. So SAD was a surprise to me and them, and SAD exists.

Can’t SAD, then, explain some of the ostensibly unexplainable outcomes at this point in the NBA season? One night Kobe might rather read a book than a defense. One week LeBron might rather dunk cookies than basketballs. One month Dwight might rather watch Seinfeld reruns than Grunfeld’s team run. If any of these things happen, losses to worse squads don’t seem so surprising.

Players would never admit it, but maybe sometimes they’re just down, just SAD. In a league filled with athletes so competitive and skilled, the slightest deficit in energy and intensity could be enough to turn an easy win into a disconcerting loss.