More than a decade after it was legalized, physician-assisted suicide appears to be on the increase in parts of Belgium, according to a study in the journal JAMA Internal Medicine.

In the Netherlands, where euthanasia is also legal, another study appearing in the same journal found the practice was rarely used.

The impact of making physician-assisted suicide legal continues to be scrutinized by the global medical community, ethicists, lawmakers and the public. Both studies were released Monday.

In Flanders—the Dutch-speaking, northern part of Belgium—euthanasia increased to 4.6% of a sample of 3,751 deaths in the first half of 2013, up from 1.9% of a similar sample during the first half of 2007, according to surveys of physicians conducted by mail.

In the 2013 study, more than 75% of requests were granted, up from about 55% in 2007. The number of requests increased as well, it found.