Data from Denmark showed those growing up in the most polluted areas had a rate of schizophrenia almost 1.5 times higher than those in the least polluted areas. Picture: AP

Exposure to air pollution, particularly in childhood, may raise the risk of depression and bipolar disorder, a US-led study shows.

Researchers studied health insurance data from 151 million people and found areas with the worst pollution had a 27 percent higher rate of bipolar disorder and a six percent higher rate of major depression, PLOS Biology reports.

Data from Denmark showed those growing up in the most polluted areas had a rate of schizophrenia almost 1.5 times higher than those in the least polluted areas.

But Dr Daniel Maughan of the Royal College of Psychiatrists said: "There are many environmental factors which could contribute to poor mental health for those people living in areas of high pollution. It is therefore difficult to isolate poor air quality as the cause."

Here are ways to help a depressed person: 

  • Focus on listening, not lecturing. Resist any urge to criticize or pass judgment once a person begins to talk. The important thing is that the person is communicating. 
  • Be gentle but persistent. Don’t give up if they shut you out at first. Talking about depression can be very tough. Even if they want to, they may have a hard time expressing what they’re feeling. 
  • Acknowledge their feelings. Don’t try to talk the person out of depression, even if their feelings or concerns appear silly or irrational to you.
  • Trust your gut. If your teen claims nothing is wrong but has no explanation for what is causing the depressed behavior, you should trust your instincts.

Daily Mail