[UPDATE: FWIW, here's a somewhat different view on 'P,' from psychiatrist Sally Satel, which rather demonstrates Blair's thesis. Feel free to comment at will.
Now I enjoy a good moral panic as much as the next person, but I think methamphetamine deserves its dreadful reputation. No other addictive drug combines so expertly the seduction of intoxication (feelings of supreme confidence and energy) with duration of intoxication (over 10 hours) with memory and concentration deficits (presumably reversible) and paranoia (usually reversible). Because the drug inflames the sex drive for hours on end the large number of different partners in a given session virtually ensures high rates of sexually transmitted diseases such as HIV and syphilis.]