nightmarish they are...
i think this happens from the deprivation of REM during use of amfetamine resulting in a night loaded with REM as soon as the use stops. i know some quiet heavy pepusers and indeed they often report of nightmares, but as we know that intense use of amfetamines makes the users somewhat 'freaky' while they believe they're not, well, almost none of those i know 'believes' dreams can be real, reality is what happens in the world around them, not inside their minds...