Anecdotal evidence, something that happerned to someone, at some place, but somehow it must be true. Anecdotal evidence is evidence that is not actually empirical, not really considered scientific, yet even so, many scientific theories, especially in psychology and medicine began in such a way.
And Grinspoon and Bakalar (1998) ask the question to what extent we should actually accept such evidence in decision making. In the United States, drugs must go through an intense testing process to be legally authorised to be prescribed by doctors. This typically involves animal testing, followed by double-blind controlled studies with humans and analysis over what the new drug brings over currently available drugs.
It is argued that this process stifles the ultimate creativity of discovering new medical solutions, a point which is exemplified through testimonials that cannabis has resolved bipolar mood disorder more effectively than the lithium based medications advised by doctors.
Grinspoon and Bakalar (1998) share multiple accounts from people, who accidentally discovered that cannabis made them feel normal again, after contending with manic-depressive or bipolar disorders, including an account from a medical professional, who, after discovering her son had been taking the drug, researched it further and became convinced of its effectiveness.
The challenge is that cannabis has had a history as an abused drug, used for pleasure, and which is also illegal, making it very difficult to carry out actual scientific studies as to if the capability and safety of this drug could be empirically verified.
The risk of accepting the anecdotal evidence is that we discount the negative impacts, seeing only the positive effects, whereas if scientific (empirical) evidence is followed, the failures are maximized and the positives are regarded as but a corroborating yes, yet to be scrutinized.
Here’s how I see it: the accounts described by Grinspoon and Bakalar (1998) are certainly convincing. I am not a fan of using drugs to control psychological disorders, however I believe there are times when it does become the better option. Cannabis is a drug, like any other, medical or non-medical. If this drug can be understood, and seen to be reliable in overcoming bipolar or manic-depressive disorders, then it would be reasonable to make it available clinically, just as any other prescription drug.
Grinspoon, L. & Bakalar, J. B. (1998). The Use of Cannabis as a Mood Stabilizer in Bipolar Disorder: Anecdotal Evidence and the Need for Clinical Research. Journal of Psychoactive Drugs, 30(2), 171-177.