PROVIDENCE — The commission charged with exploring how much money the state could reap if it legalizes marijuana and taxes its sales will meet for the first time Wednesday.

Lawmakers voted to create the nine-member panel in July, the day before the General Assembly began its summer recess. Its first meeting is slated for 3:30 p.m. in Room 212 of the State House.

The group intends to study issues surrounding the state’s position on marijuana, including money the state might make if it legalized it and enacted a $35 “sin tax” for purchases of an ounce or more.

Other topics to be explored are the effects and costs of Rhode Island’s prohibition of the drug, except to sick people; whether adult use has increased since it was banned in 1918; whether its sales are financing drug cartels and fomenting violence; and its current availability to young people. The group will also look at how states and countries that have decriminalized the drug have fared.

One of the first subjects the panel will examine is Massachusetts’ experience since voters there overwhelmingly approved a ballot measure in November 2008 that decriminalized possessing small amounts of marijuana. People caught with less than an ounce face a $100 civil fine, but not criminal charges.

The group will gauge the effectiveness of that state’s policy and its impact on law enforcement and prison resources, said Sen. Joshua Miller, D-Cranston, one of five sponsors of the bill that created the commission.

The panel also hopes to assess how marijuana use compares with alcohol, in terms of costs to society, he said. Miller, a restaurant and bar owner, has said he does not use illegal drugs and rarely drinks alcohol.

The state’s stance on marijuana has evolved in recent years. The General Assembly gave final passage to a law in 2006 allows patients with debilitating medical conditions, such as cancer, HIV and multiple sclerosis, to possess up to 12 marijuana plants or the equivalent of 2.5 ounces of marijuana at any one time.

In May, legislators overwhelmingly passed a bill that allowed state-regulated marijuana dispensaries, known as compassion centers, so patients wouldn’t be forced to grow or buy marijuana on the street.

However, a bill that would have decriminalized marijuana possession in Rhode Island by imposing a civil fine on anyone caught with an ounce or less failed. Submitted by Leo R. Blais, R-Coventry, another sponsor of creating the study commission, never made it out of the Senate Judiciary Committee.

Miller will be joined on the commission by: Glenn C. Loury, an economics professor at Brown University; Nick Horton, of OPENDOORS, formerly the Rhode Island Family Life Center; Donna Ploicastro, executive director of the Rhode Island Nurses Association; Dr. David C. Lewis, of Brown’s Center for Alcohol and Addiction Studies; and Jeffrey Alan Miron, who teaches economics at Harvard University.

It was unclear Sunday who the other three members are, but the group is supposed to include local police as well as advocates or patients of the state’s medical-marijuana program.

The commission will meet at least three times before it is due to submit a report on Jan. 31, Miller said.

kmulvane@projo.com