New research at the Washington University School of Medicine in St. Louis reveals that smoking increases the risk of individuals committing suicide.

Past studies have revealed that smokers have higher suicide tendencies than non-smokers, but it was linked to the finding that people that have psychiatric disorders, which are those that have higher rates of suicide, are also usually smokers.

This new research directly links the act of smoking itself to suicide, as policies that limit smoking in specific areas also bring down suicide rates.

The study was published on July 16 at the Nicotine & Tobacco Research journal by the team of Richard Grucza, a psychiatry associate professor.

The team's research showed that in states where there are taxes on cigarettes are higher compared to other states and where policies to limit public smoking are strictly implemented, suicide rates showed a decline of up to 15 percent compared to the country's average.

"Our analysis showed that each dollar increase in cigarette taxes was associated with a 10 percent decrease in suicide risk," Grucza said.

He added that bans on smoking in indoor locations also led to reductions in suicide risk.

Each state uses a different approach in levying taxes on cigarettes and reducing the places and times for smoking. According to the study, the states that implemented aggressive policies to control smoking from 1990 to 2004 experienced decreased suicide rates compared to the country's average. The trend is in stark contrast compared to the states that implemented lower taxes and more relaxed policies, which saw suicide rates go up six percent compared to the country's average.

"If you're not a smoker, or not likely ever to become a smoker, then your suicide risk shouldn't be influenced by tobacco policies," said Grucza. "So the fact that we saw this influence among people who likely were smokers provides additional support for our idea that smoking itself is linked to suicide, rather than some other factor related to policy." 

According to information from the Centers for Disease Control and Prevention, suicide is the 10th leading cause of death in the U.S. Every suicide case that occurs in the country is filed in a database that is operated by the National Center for Health Statistics.

Grucza and his team of researchers categorized each case of suicide according to the location of the victim, and compared the numbers to the strictness of the tobacco policies on the said locations.

Grucza thinks that nicotine could be a major factor in the risk of suicide. He also expresses concern on how e-cigarettes are not covered by tobacco restrictions, when the new smoking devices also utilize nicotine.

Nicotine, as any other drug that could lead to addiction, is first taken to feel better, then continued to be taken to feel normal, according to Grucza. Chronic usage of nicotine may lead to anxiety or depression, which links to suicide.