Mad Mix of Mental Illness and Marijuana?

Welcome to Politics Bites, where every afternoon at It's A Free Country, we bring you the unmissable quotes from the morning's political conversations on WNYC. Today on the Brian Lehrer Show, forensic psychiatrist Dr. Michael Stone explored what can be ascertained about Jared Loughner's mental state ahead of the Tucson shooting.

Arizona's shooting just a few days ago is just the latest mass casualty shooting in the U.S in recent years five years. Two other high-profile cases at Virginia Tech in 2007 and Fort Hood in 2009 stoked conversations about mental illness and weapons. The Tucson massacre, as did the other shootings, has ramped up the political talk for better gun control legislation around mental health.

Jared Loughner, the accused gunman in Saturday's shooting, had symptoms that lead Dr. Michael Stone to believe he may have been mentally unstable and Stone says his apparent heavy use of marijuana can tell us a lot as well. According to Stone, using marijuana at an early age can not only exacerbate mental illness, but can even cause it.

There's a certain proportion of adolescents who are very susceptible to the effects of marijuana and if they abuse it before the age of 17 or 18, they're very likely to begin having persecutory ideas, paranoid ideas. They may have auditory and visual hallucinations. And they end up with a condition that looks for all the world like paranoid schizophrenia.

Stone said Loughner may have had a predisposition to mental illness, but it's likely that drugs played a role in his instability. Stone said the political context of an angry Arizona district probably stirred the pot as well.

If you're in an area, an atmostphere where there's a lot of controversy and electrifying comments about a particular situation... and you then put into that mix a person who is becoming increasingly paranoid or deranged... those people are more apt to be swept along and they become intensely preoccupied with whatever is the topic of the day... I think he was swept up in the current there.

In the aftermath of Tucson, some politicians are calling for more gun restrictions for mentally ill people. But Stone says mental illness rarely leads to violence. He says 95 percent of mentally ill people with psychosis lead their lives without ever commiting a violent act.  But the likelhood of violence increases when you add drugs to the equation.

Ones who are paranoid and who, in addition, abuse drugs, whether it be alcohol, marijuana or cocaine, that increases the likelihood just about off the charts.

Many listeners found the cannibus connection a silly one, but Stone isn't the only one who's found it. Conservative columnist David Frum has seen it too, and put together a list of scientific research on the topic.

Mayor Bloomberg is one of many politicians who has spoken out in favor of stricter gun control, including background checks. In a press conference on Tuesday, he called Loughner "a mentally ill drug abuser who had access to guns he shouldn't have."