A new study has found that people suffering from depression, anxiety and other mental disorders are more than twice as likely to spark up an e-cigarette and three times as likely to “vape” regularly than those without a history of mental issues.

Researchers at the University of California, San Diego drew their findings from an extensive survey of American smoking habits. Among 10,041 respondents, 14.8% of individuals suffering from mental health disorders said they had tried an e-cigarette, compared with 6.6% of individuals who had no self-reported history of mental disorders.

The e-smokers’ elevated rates of mental disorders reflected the elevated rates of mental illness among smokers in general. The authors note that by some estimates, people suffering from mental disorders buy upwards of 50 percent of cigarettes sold in the U.S. annually.

Many respondents said they switched to e-cigarettes as a gateway to quitting. The FDA has not yet approved e-cigarettes as a quitting aide.

“People with mental health conditions have largely been forgotten in the war on smoking,” study author Sharon Cummins said in a university press release. “But because they are high consumers of cigarettes, they have the most to gain or lose from the e-cigarette phenomenon.”

The study will run in the May 13 issue of Tobacco Control.

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