"While assisted suicide is strictly restricted in many countries, it is not clearly regulated by law in Switzerland. This imbalance leads to an influx of people—'suicide tourists'—coming to Switzerland," Gauthier wrote.
Gauthier identified 611 cases of people, ranging in age from 23 to 97, who came to Switzerland to organize their own deaths with the help of "right to die" groups such as Dignitas.
"The main reasons were neurological disease (47 percent), followed by cancer (37 percent), rheumatic and cardiovascular disease," Gauthier writes.
Most came from Germany and Britain but the number of Italians coming ballooned from four in 2009 to 22 in 2012, while the numbers from France nearly tripled from seven in 2009 to 19 in 2012.
—By Maggie Fox, NBC News