Ever since humans first created maps, we’ve had a compulsion to fill them in. Our desire to see what lies beyond that distant peak, that vast sea, or this planet is an essential part of who we are, and studies show that our inherent wanderlust can also make us smarter, happier, and more creative.

But is it possible to overdose on too much of a good thing? Can this natural instinct to see and better understand the world actually spill over into a legitimate addiction?

“The short answer is yes, it's possible,” says Dr. Michael Brein, a social psychologist who specializes in travel and intercultural communication. “But figuring out what causes it is incredibly complicated.”

It’s a question that’s been puzzling experts since 1886, when a French gas-fitter named Jean-Albert Dadas wandered into a hospital in Bordeaux. After deserting the French army five years earlier, the “pathological tourist” relentlessly crisscrossed Europe on foot for five years, reaching Berlin, Prague, Moscow, and Constantinople before succumbing to exhaustion. By the time Dadas arrived in Bordeaux, he had no memory of his travels.

After treating Dadas for several weeks, psychiatrists sought to explain his extreme version of the travel bug with a diagnosable condition: “dromomania."

Sometimes called “vagabond neurosis,” the term was officially added to the Diagnostic and Statistical Manual of Mental Disorders as an “impulse-control disorder” and “psychiatric problem” in 2000. The definition states: “sufferers have an abnormal impulse to travel; they are prepared to spend beyond their means, sacrifice jobs, lovers, and security in their lust for new experiences.”

“Travel addiction is much more psychological [than biochemical],” Dr. Brein says. “Like anything, if you let it overwhelm you, it can have serious effects on other aspects of your life.”

If you make it your life’s mission to go to obscure towns and territories like Aargau, Zug, and everywhere in between, does that bring you closer to knowing the world or take you further from reality?

While no one (that we know of) has blacked out on a multi-year odyssey since Dadas’s epic trance, the term “dromomania” has recently reemerged as a common way to describe and diagnose a new breed of extreme wanderers: competitive travelers. Fueled by time, money, and compulsion, competitive travelers dedicate their lives to going—literally—everywhere. Sometimes called “country collectors” or “tickers,” they've carved the world into an endless jigsaw puzzle of cities, provinces, regions, territories, atolls, oblasts, and impossibly remote volcanic specks, and race around the globe accumulating places the way other people collect stamps. What drives them is somewhat paradoxical: They’re on a quest to “know” the world, and to keep score while doing it.

Today, between sites like Most Traveled People, The Best Travelled, and Shea’s ISO List that keep a running tally of each collector’s territory total, there are more than 30,000 humans actively competing to be crowned the world’s most traveled person. It’s a fascinating case study: If you make it your life’s mission to go to obscure towns and territories like Aargau, Zug, and everywhere in between, does that bring you closer to knowing the world or take you further from reality?