The effects of methamphetamine and secobarbital on the contingent negative variation amplitude

The amplitude of the contingent negative variation (CNV) was studied in twelve male subjects given oral doses of methamphetamine (10 mg), secobarbital (50 mg), and placebo on the three testing days separated by one week. Orders were balanced across subjects and testing conditions were double-blind. The mean amplitudes of the CNV elicited with methamphetamine were significantly greater than those obtained with secobarbital and placebo. Comparing secobarbital with placebo yielded no significant results, possibly due to the low secobarbital dosage. The sensitivity of the CNV amplitude to methamphetamine suggests that the CNV may be a sensitive measure of arousal and attention and could provide a reliable index for assessing the relative arousal effects of complex drugs on humans.