The efficacy of L-tryptophan in the reduction of sleep disturbance and depressive state in alcoholic patients.

Alcoholic male inpatients (N = 76) served as subjects in this study which examined the effect of L-tryptophan on depressive state and sleep disturbance. All subjects were residents of a 6-week alcohol treatment program at a Veterans Administration Medical Center. Subjects' degree of depression (Zung's Depression Scale) and sleep satisfaction (Webb's Post-Sleep Inventory) were measured four times during the study, just prior to and following ingestion of a substance that was either 3 gms L-tryptophan or 3 gms of an identical-appearing placebo. Subjects in the L-tryptophan/placebo condition received the active substance for 4 days followed by the placebo with a 4-day washout period in between. A second group of subjects received the same regimen of reverse order and a third received placebos on both occasions. There were two additional control groups that received no substances. All subjects in the study reported decreased levels of depression due to nonspecific treatment effects. The subjects who took L-tryptophan in either sequence reported even lower levels of depression. Sleep disturbance was not affected by L-tryptophan since it was barely present when the study began. A phenomenon referred to as the interval effect is discussed and an alternative explanation for this effect is offered.

RCT Entities:   Population Interventions Outcomes