Add to these internal mechanisms the shame and negative social conditioning about weight and the deck is seriously stacked against people trying to control their intake of food.
An additional refinement is major analyst jockeys on these volatile growthies use a dividend discount model which gives weight to the negative impact of drug patent expirations 5 to 10 years out.
In other words, investors are giving the patent challenge more weight than they rationally should because a negative outcome--as seen with Prozac--would be so painful.