A comparison of assessment techniques measuring the effects of methylphenidate, secobarbital, diazepam and diphenhydramine in abstinent alcoholics

Abstract

In two studies, we studied the comparative sensitivity of different subjective and objective measures to methylphenidate (10 and 20 mg) and secobarbital (100 mg) versus placebo, and diphenhydramine (50 mg) and diazepam (10 and 20 mg) versus placebo in abstinent alcoholics. Subjective measures used were the Visual Analog Mood Scale and the Profile of Mood States. Objective measures were the Stroop and two microcomputer-controlled tasks developed in our lab - a dual pursuit tracking/reaction time task (P-Trak) and a reaction time task with regular and irregular preparatory intervals (PI) of varying length (Reactest). In addition, several baseline measures (Eysenck Personality Inventory, Spielberger State-Trait Anxiety Inventory and NIMH Mood Scale Elderly) were evaluated for their correlation to drug response. All three central nervous system depressants impaired performance on Reactest at the longer PIs and showed a main effect with irregular PIs, but only the 20-mg dose of diazepam impaired reaction time at the shortest PI and showed a main effect with regular PIs. On P-Trak, secobarbital and diazepam 20 mg impaired both tracking and reaction time, while methylphenidate 20 mg improved only the reaction time component. Only diazepam 20 mg affected mood. No effects were noted on the Stroop. The implications of these findings are discussed. Both P-Trak and Reactest with long PIs were more sensitive than VAMS, POMS or Stroop to drug effects. As lower doses of central nervous system depressants impaired reaction time only with longer PIs and showed a main effect only with irregular PIs, cognitive effects of these drugs may be missed if only subjective or short, regular PI tasks are examined.(ABSTRACT TRUNCATED AT 250 WORDS)