Mental health experts believe that depression results from changes in the levels of chemicals in the brain and the body.

"Each year we delay means 10 more years before the levels of harmful chemicals in the atmosphere come down."

It works by increasing the levels of certain chemicals in the brain.

The forskolin group also had lower levels of inflammatory chemicals in their urine, the study shows.

Giving drugs to fix the level of certain chemicals in the blood.

Living or working in an area with high levels of air pollution, chemicals, or dust.

So, the pancreas works to keep the level of chemicals in balance in the body.

The study sought to determine whether measuring the levels of such chemicals could predict violent behavior.

When levels of certain chemicals become too high, the patient develops mania.

Or they may point to long-term contact with low levels of chemicals at work, perhaps while working in an office with poor ventilation.