By Timothy Fong

I not only play fantasy sports; I study them. Fantasy sports are online games in which people assemble virtual teams of real-life players and compete against other virtual teams based on statistical performances.

While money is often involved, these games are not seen as gambling by the federal and most state governments. But for me, an addiction psychiatrist who co-directs UCLA’s Gambling Studies Program, it has become harder to tell the difference.

Last year, I was one of 50 million people who played fantasy sports; I spent Thanksgiving playing daily fantasy football. My son and I opened an account on one of two major companies that organize daily fantasy—a fast-paced and hugely popular version of fantasy sports that squeezes online competition into a single day as opposed to an entire season. An entry fee of $50 allowed me to assemble a team of NFL players and pit them against the roster of another anonymous user. The website compared our players’ stats side-by-side in real-time, and awarded $90 ($50 from him, $50 from me, and $10 to the website) to the team that had the most points at the end of the day’s games.

My desire to win surprised me. Every time one of my players did well, I felt a rush of excitement. Every time one of my opponent’s players did well, I felt a pang of frustration. As the games wound down and it became clear I would lose $50, I felt unsatisfied—not at the idea of losing money, but at the idea of losing to someone I didn’t know.

This daily version of fantasy sports rapidly emerged in American popular culture last year, in part through a $250 million advertising push. The companies, which include DraftKings and FanDuel, aren’t regulated like traditional forms of gambling, and the companies argue that they shouldn’t be, on the grounds that they’re games of skill. But in recent months, some states have moved to classify daily fantasy sports as gambling, arguing that they’re actually games of chance.

The week after Thanksgiving, I played a second round of games because I had money left over in my account. I played against another faceless avatar, and lost. My opponent and I coincidentally had chosen almost the exact same roster (had I been able to see his roster ahead of time, I would have picked other players). He won because his tight end caught a touchdown, and mine did not. He lucked into picking the right guy on the right day.

The season-long version of fantasy sports never feels this random. Those games are measured, nuanced, and definitive, and the winner earns victory by outmaneuvering the rest of the league. I’ve played season-long fantasy sports for more than 20 years. There are nine people in my baseball league, and it’s always the same three who fight for the top and the same three who finish at the bottom.

In daily fantasy sports, players wager money on an event of uncertain outcome in the hopes of winning more money. That feels like gambling, because that’s the essence of the gambling experience. The layouts of daily fantasy sports websites look exactly like online poker and Internet sports gambling websites, with slick graphics and tantalizing promises of big wins.

Gambling is meant to be recreation. And for most people who do it, it’s a diversion, an escape. I remember the first bet I ever made, a losing $20 wager that the Chicago Cubs would win the 1993 World Series. I lost, but it imprinted in me the experience of a wager—the anticipation, the excitement, the optimism, the denial, and ultimately the acceptance of defeat. Gambling disorder, meanwhile, is a psychiatric condition that affects 2 percent of the population. It’s characterized by addiction: continued gambling despite harmful consequences, even after defeat.

Daily fantasy sports websites are anonymous, easy to access, and even easier to hide. Anyone could place thousands of dollars at risk with a click of the mouse, and no one close to them would know. This is where the risk to develop addiction is highest. There is no maximum amount of money to be lost, and there are no consumer protections.

Today, my daily fantasy sports account sits at $49, with enticements like “deposit more” and “get back in the game.” Every once in a while, I’ll log on to see what games are being offered. But the draw for me to play is low. I know I won’t enjoy the experience. Besides, the NFL season is over and I need to get my fantasy baseball team in order.

Timothy Fong is an associate professor of psychiatry at the University of California, Los Angeles, where he co-directs the UCLA Gambling Studies Program. He is a lifelong Chicago Cubs fan.