Rounding up commentary pushing back on efforts to link marijuana, psychosis and violence

I have noted the new book by Alex Berenson, "Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence,"  through his recent commentaries spotlighted here and here, as well as through Malcolm Gladwell's New Yorker essay about the book.  The core message of Berenson's book, namely that more marijuana use thanks to legal reforms is leading to more mental illness and more violence, is now generating a whole lot of push back.  Here is just a partial round-up of new commentary expressing concerns about Berenson's claims:

• By Aaron E. Carroll, "The Reasonable Way to View Marijuana’s Risks: Cannabis has downsides, but speculation and fear should be replaced with the best evidence available."

• Also by Aaron E. Carroll, "A more thorough analysis of marijuana use and homicide in Colorado and Washington"

• By James Hamblin, "If Legal Marijuana Leads to Murder, What’s Up in the Netherlands?: A terrifying argument that cannabis causes homicides sparks a debate over whether the drug is more dangerous than its criminalization."

• By German Lopez, "What Alex Berenson’s new book gets wrong about marijuana, psychosis, and violence: The book, Tell Your Children, has received a lot of media attention, but it’s essentially Reefer Madness 2.0."

• By Jesse Signal, "Did Marijuana Legalization Really Increase Homicide Rates?"

The debates over the data and how to respond to what we know and do not know is fascinating. And, helpfully, this morning The Marshall Project has this great new piece headlined "How Dangerous is Marijuana, Really? A Marshall Project virtual roundtable." Here is how the Marshall Project sets up a fascinating discussion:

On Jan. 7, The Marshall Project published an interview with Alex Berenson, a former New York Times reporter and author of "Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence," which warns that the rush to legalize the drug has obscured evidence of its dangers.  The interview stirred up a storm on social media, so we decided to enlarge the discussion.

What follows is a conversation, conducted by email and moderated by Bill Keller, editor-in-chief of The Marshall Project.  Berenson is joined by three other panelists. Maria McFarland Sánchez-Moreno is the executive director of the Drug Policy Alliance, a non-profit that advocates ending the war on drugs, including the "responsible regulation" of marijuana.  Its donors include companies in the legal, for-profit cannabis industry, whose gifts, the group reports, made up less than 1 percent of the alliance’s 2018 revenue. Keith Humphreys is the Esther Ting Memorial Professor at Stanford University. He has been deeply involved in drug policy as a researcher and White House advisor.  Mark A.R. Kleiman is a professor of public policy at the New York University Marron Institute of Urban Management, where he leads the crime and justice program. He is also chairman of BOTEC Analysis, which advises Washington State and Maine on cannabis regulation.

The discussion has been lightly edited for length and clarity.

The Marshall Project: This first question is for all of you. Let's start with the core question Alex set out to answer in reporting his book: What do we know about the connection between marijuana and mental illness? What would you say is established medical science, and what is still unresolved?