Nonspecific treatment response is common in pharmacotherapy trials for alcohol dependence, and results in a marked decrease in alcohol consumption even before subjects' enrollment in a treatment study. We propose that nonspecific effects are associated with trait and state factors operating prior to treatment to influence participants' expectation/perception of future treatment outcome and their drinking behavior. Trait factors include personality, and state factors include readiness to change and severity of drinking at screening. Our study goal was to determine how these nonspecific effects contribute to pre-double-blind clinical outcome.

We examined the association of trait factors (gregariousness or conformity on MacAndrew Alcoholism Scale (MAS)) and state factors (stages-of-change scale, level of drinking at screening) with pre-double-blind clinical outcome among 321 alcoholics in a pharmacotherapy trial.

Nonspecific effects were associated with significant reduction in alcohol consumption among heavy drinkers (10.3±5.9 drinks/day at baseline vs 5.3±5.1 drinks/day during the last week of single-blind treatment; p<0.001) but not non-heavy drinkers (3.07±0.65 vs 2.98±2.6; p>0.05). Partial correlations indicate that significant predictors of pre-double-blind drinking reductions were: level of drinking (–0.215) and the stages-of-change subscales of pre-contemplation (–0.152), contemplation (0.144), and the struggle to maintain (–0.284). The MAS did not predict pre-double-blind drinking reductions.

Participants with higher motivation levels and greater drinking severity were most likely to experience nonspecific treatment effects before double-blind treatment. Gregariousness and conformity were not associated with nonspecific treatment effects.