Some scientists say weed helps depression. Some say it causes depression. And some are too stoned to say anything at all.

The link between marijuana and depression has long been blurry. Individuals who have been using marijuana for decades may have a higher disposition to depression according to one recent study.

The study was published by the National Academy of Sciences and links both anxiety and depression to Maryjane. The study compared the reaction of those who use marijuana on a regular basis with those who do not by testing their reaction after being given Ritalin. The results showed that those who frequently smoke pot have a stunned reaction to stimulates and are more likely to be negative. Because cannabis or THC is related to increased dopamine levels in the brain, the researchers linked its use to a pessimistic outlook.

However, proponents of cannabis claimed that the study was poorly executed and does little if anything to prove a correlation between the two. In fact, Ritalin itself could have been the source and cause of the participant’s negative emotions to begin with.

Pharmaceutical companies stand to gain much financially by keeping cannabis illegal, and studies like this one are a said attempt to prove that marijuana causes depression or anxiety. In fact, there are quite a few studies that show that anxiety and depression can be treated with cannabis. Unfortunately, many of these studies never see the light of day.