The use of marijuana (cannabis) for medical purposes has been sweeping trough the U.S., as well as other parts of the world. While some studies indicate that the drug can assist with certain conditions, such as Alzheimer’s disease (if at the right age and with sufficient frequency) and the eating disorder anorexia nervosa.

To add to the use of marijuana for medical purposes, some U.S. states have also legalized it for recreational use (such as Washington state.) The U.S. is in a state of flux with this regard, for the use, sale and possession of marijuana remains illegal under federal law. Despite this, some states allow exemptions for medical cannabis use, and a few have decriminalized non-medical marijuana use.

It is the growing use and lack of in-depth research that concerns Christian Hopfer, a psychiatry researcher at the University of Colorado School of Medicine in Aurora. Dr. Hopfer was recently interviewed for the website of the science magazine Nature. The key issue is that “evidence for marijuana’s effects on health and behavior is limited and at times conflicting.”

Here. Dr. Hopfler notes: “Broadly speaking, there’s about 100 times as many studies on tobacco or alcohol as there are on illegal substances. I don’t think it’s the priority it should be.”

There are concerns about the effect of marijuana on memory and coordination, as well as links between the drug on feelings of paranoia and displays of psychosis among users.

It would seem that if the use of marijuana is to be extended in some parts of the world, more resources and time need to be out into researching the effects of the drug.