causes of mental illness

Cleaning shirts shouldn't be triggering bipolar disorder or anxiety.

The industrial solvent used in the majority of American dry cleaners has always been risky business. Perchloroethylene is suspected of causing kidney and liver damage and nervous system problems, and, according to a newly released evaluation of the chemical by the Environmental Protection Agency (EPA), it's likely to cause cancer.

For the first time since 1988, the EPA re-evaluated the health hazards associated with perchloroethylene (also called "perc") and, for the first time, dubbed it a likely human carcinogen. The chemical hadn't been evaluated for a cancer risk before, but the agency changed its tune after reviewing dozens of animal studies as well as studies on workers that showed higher rates of bladder, non-Hodgkin lymphoma, and multiple myeloma (a cancer of the blood) in people exposed to high levels.

That gives the agency more authority to set more stringent standards for the 500 million pounds of the chemical produced in the U.S. each year, some of which can wind up in drinking water, dumped not just by dry cleaners, but also by metal workers, auto garages, and chemical and electronics manufacturers.

It isn't just cancer that people should be worried about either. Researchers from Boston University have linked the chemical to bipolar disorder and post-traumatic stress disorder (PTSD), at levels that are considered "safe."

Researchers at Boston University analyzed 11 years' worth of data on 1,512 people who were born on Cape Cod, Massachusetts, an area that suffered a great deal of perc pollution during the '60s and '70s as a result of its use of a certain type of adhesive in the city's drinking-water-supply pipes. All the participants filled out questionnaires relating to their mental health, as well as other factors that could influence mental illnesses, such as family history or occupation.

Regardless of those other factors, exposure to perc in any amount was related to an 80 percent increase in risk of bipolar disorder and a 50 percent increase in risk of PTSD. The chemical was also associated with an increased risk for developing schizophrenia, and even though just four adults in the entire group developed the condition—too small a number to draw any meaningful conclusions—the authors thought it was interesting that three of the four were exposed to perc. In addition, previous studies have linked the chemical to increased anxiety levels and depression in adults.

Ann Aschengrau, ScD, professor and associate chair of the department of epidemiology at the Boston University School of Public Health, says it isn't really clear what role perc is playing in the development of mental illnesses. "We suspect that this would work in some way to make you more susceptible to other things that happen in your life," she says. "Say, for PTSD, in order to develop it, you still have to have a traumatic episode, but not everyone who has a traumatic episode develops PTSD. Maybe this makes you more susceptible to it."

Though most of the people with mental illness had been exposed to perc at extremely high levels, some were exposed to levels as low as 1.5 parts per billion, Aschengrau said. The Environmental Protection Agency (EPA) has set a "maximum contaminant level" of 5.0 parts per billion, the level at which municipal water supplies are required to take extra steps to get the chemical out of water, but in light of the new cancer designation, that's probably going to change. They also set a non-enforceable "human health water quality" limit of 0.69 parts per billion. According to a 2009 study by the Environmental Working Group, 27 municipal water suppliers tested positive for perc at levels above the legal limit of 5.0 parts per billion, and 40 were above the EPA's human health recommendation.