Let us imagine that a patient has just been admitted to the Day Ward in order to receive treatment with a chemotherapeutic agent or drug: Adriamycin perhaps, or one of the platinum-based drugs.  As it enters the bloodstream, toxic side-effects produce feelings of nausea, possibly accompanied by an instant compulsion to retch. Maybe it is around lunchtime and the meal wagon has just entered the ward. If only from the aroma surrounding it, it is evident that fish is very much on the menu for that day – possibly a Friday. In the ordinary way, the patient concerned enjoys a fish meal. However, on this particular day, he/she has far too much on their mind to be interested in food.

Some two weeks later, the same patient – now well into the rest and recovery phase – is feeling much improved and returning to normal. That is, until (possibly without consciously linking the association at all) he/she experiences a sudden and violent need to retch. The truth of the matter is that he/she has just passed the open door of a fish restaurant and “bingo”; the smell of fish alone has done the rest.  It might not – indeed, it is unlikely to – have been precisely the same smell in every detail; but it is fish and certainly near enough (note the “stimulus similarity”) to produce the reaction of nausea and even vomiting. (Interestingly enough, the nature as well as the strength of such a response as that referred to above – which, as I hope you can also see, is entirely normal and all part of the way in which we learn – can and does vary from individual to individual.

One further important point needs to be made explicit. The selection (if I might put it that way) of ‘what experience pairs or bonds with what’, is likely to be determined and ‘laid down’ by the presence, at that same moment in time of a powerful feeling or emotion (sometimes referred to as the “bonding agent”). In the case of Pavlov’s dogs this bonding agent was hunger and in the case of our hypothetical patient on the ward at lunchtime, it was apprehension, uncertainty and even downright fear. Once established, its behavioural component can be evoked at anytime (as indeed we can witness in the event referred to recently, occurring in the Sauchiehall Centre in Glasgow). Fortunately – and as we shall subsequently witness in a future “prescription” – the loosening and elimination of such troublesome and unwanted ‘pairings’; or “de-conditioning”, as it is sometimes referred to, is perfectly feasible and achievable.

The simple fact is that we ‘human animals’ have evolved over millions of years and as we noted in an earlier letter, possessed and continue to possess remnants of a defence mechanism, which once was crucial and central to our very survival. Thus, in our hypothetical patient referred to above, the need to retch and the smell of fish engaged that same neural link between gut and brain. This happened – as it happens in others – in very similar fashion to the manner in which it did in the primitive state. Upon the ingestion of some poisonous or toxic substance – possibly a berry or whatever – it caused the gut to promptly emit it. Presumably, this is one very good reason why I am still around to ‘tell the tale’ and you to read it.