here's other concerns..

Despite its therapeutic potential, some people are wary of memory-altering drugs. Chief among them: the President's Council on Bioethics, an advisory group of doctors and scholars formed in 2001. In its report, the council worries that dampening painful memories – or in the future, erasing them altogether – may disconnect people from reality or their true selves.
"The use of memory-blunters at the time of traumatic events could interfere with the normal psychic work and adaptive value of emotionally charged memory," the council wrote. "A primary function of the brain's special way of encoding memories for emotional experiences would seem to be to make us remember important events longer and more vividly than trivial events."
In other words, emotional memories, however painful, serve a purpose. We remember memories linked to emotions longer and better because they help us learn, adapt, survive. Early hominids needed to know and remember that lions were dangerous. Modern children burn their fingers on a match and learn that fire hurts. We all learn to avoid bad things by remembering bad experiences.
Council members fret that dampening traumatic memories with beta blockers may short-circuit "the normal process of recovery," that in some way it may diminish our character or our personal development. Blocking emotional memories, the council asserted, risks "falsifying our perception and understanding of the world. It risks making shameful acts seem less shameful, or terrible acts less terrible, than they really are."
"It's the morning-after pill for just about anything that produces regret, remorse, pain, or guilt," said Dr. Leon Kass, who chaired the President's Council, to the Village Voice last year. (Kass noted he was speaking as an individual, not on behalf of the council.) The council expressed a host of concerns and troubling scenarios.
For example, the council posited, what if somebody committed an act of violence and then took propranolol to dull the emotional impact. Would they come to think of violence as more tolerable than it really is? Would rape victims, having taken memory-altering drugs to ease their trauma, forget key details vital to the prosecution of their attackers? More broadly, is there a social obligation for people to remember the past events for the communal good, such as victims of the Holocaust?
"The impulse is to help people to not fall apart. You don't want to condemn that," said Kass. "But that you would treat these things with equanimity, the horrible things of the world, so that they don't disturb you ... you'd cease to be a human being."

more at http://www.cognitiveliberty.org/neuro/memory_drugs_sd.html