Thursday, September 22, 2011

Stoned rats and post-traumatic stress disorder

Strange things pass as ‘psychological research’ these days. According to the Times of India, Irit Akirav and Eti Ganon-Elazar conducted an experiment with rats, where some of the rats were given synthetic cannabinoids (that is, marijuana) after being exposed to extreme stress (unfortunately, I have no access to the original article). A week after, some of the rats ‘did indeed display symptoms resembling PTSD in humans’—but not the ones that were administered marijuana a short while after the traumatic event. After repeating the experiment, where they injected marijuana directly into the amygdala, they could ‘conclude that the effect of the marijuana is mediated by a CB1 receptor in the amygdala’.


With the caveat that I have not read the original article, this experiment reveal some serious flaws in ‘scientific’ thinking, aside the doubtful ethics in harming animals for the sake of suffering (not as an unwelcome side effect of an otherwise important quest for knowledge, or at least potentially important).

First, how do you diagnose rats with post-traumatic stress disorder? A characteristic feature of PTSD is flashback memories, that is, unwanted and obtrusive memories or re-experiencing of the traumatic event. How do we know that the poor rats have terrifying flashbacks of the extremly stressful events the (hopefully) benevolent scientists exposed them to? How do we even know that rats have episodic memory?

The answer is simple: we don't. The poor rats cannot tell us what they experience or how they experience; they have no language. To say that rats experience post-traumatic stress disorder, is simply an anthropomorphism, that is, an attribution of human characteristics to non-human animals.

Of course, Akirav and Ganon-Elazar knows this. They don't claim that the poor rats experience PTSD; they say that the rats ‘display symptoms resembling PTSD in humans’, but by doing this, they implicitly anthropomorphize the behaviour of the rats. Indeed, the research aims at investigating the effect of cannabinoids on stress and trauma in humans, not rats. Nobody has any plans on opening a psychiatric clinic for rats, at least not that I know of.

Simply put, the fact that rats ‘display symptoms resembling PTSD in humans’ does not necessarily has anything whatsoever to do with humans experiencing PTSD. Humans have the ability of framing experiences in terms of meaning, their episodic memory is inextricably intertwined with language, and even traumatic events gain their meaning in a cultural context. This is not the case with rats. At least as far as we know, since we can't ask the rats. Structural similarity does not imply functional similarity.

Second, the way the research is conducted, it is obvious that PTSD is understood in terms of the workings of the nervous system. This is an example of the medical model of psychiatric disorders that so dominates the mental health services, at least in the western world. Simply put, all mental phenomena—ideas, feelings, sensations, perceptions, concepts, art, science, faith, consciousness, illusions and the like—can be reduced to physiology or neural functioning. Thus, all anomalies in psychological functioning and all psychological suffering, is considered a kind of malfunction in the workings of the brain, most often some kind of inbalance in the levels of particular neurotransmittors. This way of accounting for human suffering robs the sufferer of all context, of all meaning, of all that makes the sufferer human.

And what is the consequence of this revolutionary discovery? Should the emergency toolkit on regular flights include some weed, just in case of a disaster?