Critical Flicker Fusion Frequency (CFF): The Effects of Psychotropic Compounds

Critical Flicker Fusion (CFF) thresholds, self-rated changes in alertness, and psychological test performance levels, are reported from several psychopharmacological studies. CFF thresholds were based upon the average of four measures, using the psychophysical method of limits. The split-half reliability coefficient of the CFF data was highly significant (r = 0.94). In an investigation of C.N.S. stimulants (dexamphetamine, pemoline, methylphenidate), and chlorpromazine, CFF thresholds correlated significantly with self-ratings of alertness (100 mm analogue scale). Under the C.N.S. stimulant, hydergine, CFF thresholds, self-rated alertness levels, and psychological test performance levels, were all significantly raised. CFF level changes under the anxiolytic clobazam may be partially explained with reference to personality ratings; CFF values were generally elevated with high anxiety subjects, and reduced with low anxiety subjects.