A study from the University College of London has added another item to the long list of health risks of secondhand smoke — mental illness.

Research conducted on 8,155 men and women found that adults who were exposed to secondhand smoke had a higher level of nicotine residue in their blood, and as a result had a 50 percent higher risk of psychological distress, TIME.com reported.

"Clearly something is going on even at very low levels, which is quite worrying," said Mark Hamer, who led the research at the University College of London.

The findings support previous data that suggest a correlation between smoking and mood disorders, as well as nicotine in animals causing symptoms of depression, stress and anxiety.

The College of London study, published in the Archives of General Psychiatry, applied the findings to nonsmokers who spend time around people who smoke. They found that although there was a strong association to a change in mood, a direct link could not be established.

Click here to read more from TIME.com.