Rationale: Delayed beneficial effects of gabapentin on mood were frequently reported in various patient populations. This is the first controlled study which addressed acute effects of gabapentin on mood.
Methods: Analysis of the German version of Profile of Mood States (POMS) throughout a randomised placebo-controlled, double-blinded study of gabapentin on acute alcohol withdrawal [Bonnet, U., Banger, M., Leweke, F.M., Specka, M., Müller, B.W., Hashemi, T., Nyhuis, P.W., Kutscher, S., Burtscheidt, W., Gastpar, M. 2003. Treatment of acute alcohol withdrawal with gabapentin -- results from a controlled two-center trial. J Clin Psychopharmacol 23, 514-519]. In addition, subjective severity of alcohol withdrawal was determined by the Essen Self-Assessment of Alcohol Withdrawal Scale (ESA) to control effects of concurrent withdrawal on POMS. Ratings were performed at intake (baseline), day 1 (study medication 400 mg q.i.d.), day 2 (study medication 400 mg q.i.d.) and day 7 (no study medication).
Results: Analyses could be performed on 46 out of 59 randomised subjects. Within the first two days of the study, a significant stronger increase in the POMS-vigour subscore occurred in the gabapentin group. A subgroup analysis suggests that gabapentin's effect on vigour largely results from a stronger improvement of vigour in a small group of 11 patients with co-morbid mild depression (according to ICD-10: dysthymia or depressive adjustment disorder). There were no significant differences between the treatment groups regarding the other POMS-subscores (dejection, fatigue, anger) ruling out an overall fast effect on mood. Moreover, ESA-measures were not significantly altered indicating a missing effect of 400 mg gabapentin q.i.d. on acute alcohol withdrawal itself. After tapering off study medication, no more significant differences between gabapentin and placebo group were observed on vigour, strongly suggesting that the initial effect results from a pharmacological gabapentin action.
Conclusion: Gabapentin selectively accelerated the improvement of the vigour-subscore of patients with acute alcohol withdrawal within 48 h. This effect was independent from the subjective severity of withdrawal and especially marked in patients with co-morbid mild depression.