Altered Memory

60 Minutes just did a story on a drug that can "reduce" the memory of a traumatic experience. It can reduce the occurence of post traumatic stress disorder. This could be a wonderful breakthrough. It was even shown to be effective in relieving stress from old memories. Most of the debate on the episode focused on the ethics of altering a person's memories. It's a valid ethical debate but let me raise a slightly different question.

One of the patients they interviewed was a rape victim. A crime committed several decades ago. She was having many problems in her adult life because of the memories. But what if the drug had been available and used shortly or immediately after the rape occurred? The victim would not suffer the PTSD but would s/he be able to assist law enforcement in finding the rapist? If so, couldn't a halfway competent defense lawyer raise all kinds of reasonable doubt when a victim with an altered memory testified? I can see the whole testimony being struck from the trial.