A Dutch research team has disproved the urban legend that smoking marijuana boosts creativity.

A new study by researchers from Leiden University in the Netherlands claims not only is this not the case, but smoking pot may even inhibit and damage a person’s ability to be creative. Led by Lorenza Colzato of the Cognitive Psychology Unit at the Institute of Psychology at Leiden University and the Leiden Institute for Brain and Cognition, the research team recently published their findings in the journal Psychopharmacology.

For years, pot smokers have justified their use of the drug by claiming that getting high enhances their creativity. Such effects were attributed to the main psychoactive ingredient in cannabis, tetrahydrocannabinol (THC). Even Steve Jobs, the co-founder of Apple, once said, "The best way I could describe the effect of the marijuana and hashish is that it would make me relaxed and creative."

The researchers wanted to test whether different doses of THC would influence creative thinking in a positive or negative way. After signing up 59 healthy regular marijuana users (52 males and seven females), they divided them into three groups. The first group was given cannabis with high THC content (22 mg), which is equivalent to three joints of strong marijuana. The second group was given cannabis with a low dose of THC (5.5 mg) that would be equivalent to a single joint. The remaining group that probably was disappointed at first was given a placebo. None of the candidates were aware of what they were being given.

The test subjects were then required to complete a series of cognitive tasks that measured two forms of creative thinking: divergent thinking, i.e. coming up with ideas by exploring as many solutions as possible, and convergent thinking, or finding the only correct answer to a question. The low-dose THC did not significantly outperform the placebo when it came to divergent thinking, and the results were relatively equal. In other words, a little marijuana led to very little change.

On the other hand, researchers did find that the first group with a high-dose of THC were significantly impaired when it came to divergent thinking when compared to the other two groups. Such impairments included "…decreased scores for fluency, flexibility, and originality of responses of participants in the high-dose condition.” It is important to note that both low- and high-dose marijuana intake appeared to have no effect on convergent thinking among the subjects of the study.

Commenting on the team's findings, Lorenza Colzato said: "The improved creativity that (marijuana users) believe they experience is an illusion. If you want to overcome writer's block or any other creative gap, lighting up a joint isn't the best solution. Smoking several joints one after the other can even be counterproductive to creative thinking."