A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality.

Passiflora incarnata is a traditional herbal sedative, anxiolytic and a popular sleep aid used for the treatment of sleep disturbance. Several controlled experiments have demonstrated enhanced sleep in laboratory animals, but clinical trials in humans are lacking. The aim of the present study was to investigate the efficacy of Passiflora incarnata herbal tea on human sleep, as measured using sleep diaries validated by polysomnography (PSG). This study featured a double-blind, placebo-controlled, repeated-measures design with a counterbalanced order of treatments (passionflower vs placebo tea), separated by a 1 week 'washout' period. Forty-one participants (18-35 years) were exposed to each treatment for a week, whereby they consumed a cup of the tea and filled out a sleep diary for 7 days, and completed Spielberger's state-trait anxiety inventory on the seventh morning. Ten participants also underwent overnight PSG on the last night of each treatment period. Of six sleep-diary measures analysed, sleep quality showed a significantly better rating for passionflower compared with placebo (t(40) = 2.70, p < 0.01). These initial findings suggest that the consumption of a low dose of Passiflora incarnata, in the form of tea, yields short-term subjective sleep benefits for healthy adults with mild fluctuations in sleep quality.

The effect of transdermal nicotine patches on sleep and dreams.

This study was undertaken to determine the effect of 24-h transdermal nicotine patches on sleep and dream mentation in 15 smokers aged 20 to 33. Utilising a repeated measures design, it was found that more time awake and more ASDA micro-arousals occurred while wearing the nicotine patch compared to placebo. Also, the percentage of REM sleep decreased, but REM latency and the proportion of time spent in NREM sleep stages did not change significantly. Dream reports containing visual imagery, visual imagery ratings and the number of visualizable nouns were significantly greater from REM compared to Stage 2 awakenings, regardless of patch condition. However, a general interaction effect was observed. Stage 2 dream variables remained equivalent across nicotine and placebo conditions. Within REM sleep, more dream reports containing visual imagery occurred while wearing the nicotine patch, and these were rated as more vivid. The greater frequency of visual imagery reports and higher imagery ratings specifically from REM sleep suggests that previously reported dreaming side effects from 24-h nicotine patches may be specific to REM sleep. Combined with previous animal studies showing that transdermally delivered nicotine blocks PGO activity in REM sleep, the current results do no appear consistent with PGO-based hypotheses of dreaming, such as the Activation-Synthesis (AS) or Activation, Input and Modulation (AIM) models.