The mad scientist can be usefully defined as an individual who conducts scientific experiments, invents something scientific, or does original scientific research, all while suffering from both psychological and moral insanity.

Historically the mad scientist has fallen into one of two modes. The first, what literary critics have variously labelled as “Promethean” or “utopian,” roughly follows the model of the figure of Prometheus from Greek mythology: the scientist is not inherently evil, and in fact is usually portrayed as either a self-sacrificing idealist or a deluded comic figure. The scientist’s mad science is morally ambivalent and ultimately degrades the moral sensibilities of the humans it comes in contact with. The Promethean/utopian mad scientist has noble goals but fails through human weakness, both his/her own and others’.

The second mode of mad scientist, and the more common of the two, is what literary critics call the “Faustian” or “gothic.” In this mode, both the scientist and her knowledge are morally flawed, and the act of discovery — the research and experimentation — is as wicked and damning as the possession of the evil knowledge itself.

Figures like Faustus, in possession of dangerous religious knowledge, were common in Western popular culture for several centuries, but became less so after the 10th century and were replaced by figures in possession of dangerous magical knowledge. In the 12th century the figure of Merlin begin appearing in his modern form. As Irish scholar Padraig O’Riain showed in “A Study of the Irish Legend of the Wild Man” (1972), the standard version of Merlin was heavily influenced by the Wild Man figure of early Welsh poetry. Both the Wild Man and Merlin gave several things to the figure of the mad scientist. One of the most important was the notion of mental instability being inexorably wedded to special, dangerous knowledge–in the case of the Wild Man, possession by rather than of magical knowledge inevitably leading to schizophrenia or madness.

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Legitimate studies point to marijuana use as a risk factor for developing schizophrenia. Filmmaker Bruce Mohun made The Downside Of High after his pot-smoking nephew descended into severe mental illness.

A person who uses marijuana regularly is twice as likely to become schizophrenic as someone who doesn’t, with those smoking before the age of 16 being four times as likely. Acknowledgment a link between marijuana and paranoid schizophrenia does not necessarily bolster the argument for prohibition; one could argue that legalizing pot in fact help the problem, by leading to regulation, quality control, standards, and warning labels.