Young adults with elevated levels of lead in their blood might be at increased risk for major depression and panic disorders, a new study suggests.

Researchers analyzed information on 1,987 adults, aged 20 to 39, who took part in the US National Health and Nutrition Examination Survey between 1997 and 2004. Of those participants, 134 (6.7 percent) had major depression, 44 (2.2 percent) had panic disorder and 47 (2.4 percent) had generalized anxiety disorder. The average level of lead in the blood among all participants was 1.61 micrograms per deciliter.

The 20 percent of participants with the highest lead levels (2.11 micrograms per deciliter or more) were more than twice as likely to have major depression and nearly five times more likely to have panic disorder than the 20 percent of participants with the lowest blood lead levels (0.7 micrograms per deciliter).