Does legalizing marijuana make neighborhoods less safe?

Recently, my little home town of Cathedral City, California (next to Palm Springs) discussed an application from a marijuana dispensary to open a location in the city.

The City waited for a decision from the California Supreme Court regarding the legality of a local prohibition on marijuana dispensaries. Later, the Court decided that cities may turn down applications if they've passed an ordinance. So, Cathedral City will not permit dispensaries, although surrounding cities have them.

I participated in the discussion of the planning committee regarding a recommendation. Since I keep up with real estate issues, I realized that I had not read a single article discussing the benefits, or the disadvantages, of the impact on communities of marijuana dispensaries. Later, I Google'd the issue, and found that there was a small study (for sale for $35) and a large study just started by UCLA to run for a few years.

In an apartment building I owned in San Diego, one tenant had a prescription (he said) and smoked marijuana openly. It bugged the other tenants, a lot. It wasn't illegal, but it caused problems. And his friends who came over to smoke with him, weren't the people I wanted to hang around my property.