Hughes and John (1999) review the applicability of qEEG findings in SUD. They note that in numerous qEEG studies there is a consensus of increased beta relative power in alcoholism and increased alpha in cannabis and crack cocaine users. They conclude that the evidence provided by studies to date is insufficient to recommend qEEG as a routine clinical assessment tool in SUD, although it may be useful in differential diagnosis in difficult cases. A number of specific qEEG abnormalities have been described as specific to suspected neurotoxicities associated with chronic stimulant abuse. These studies (Alper et al. 1990; Noldy et al. 1994; Prichep et al. 1996; Roemer et al. 1995; Trudeau et al. 1999) based on reasonably uniform abstinence times and employing different EEG technology and analytical approaches, have produced remarkably similar findings of alpha relative amplitude excess with delta relative amplitude deficit that is striking. Excess alpha amplitude with slowing of alpha frequency associated with chronic cannabis abuse has been reported (Struve et al. 1998). As noted, Scott and Kaiser (1998) describe combining a protocol for attentional training (beta
