Coffee the hallucinogenic (Issue 12, 2011)


Daily_Mail_CartoonIn a recent La Trobe University study – The effect of caffeine and stress on auditory hallucinations in a non-clinical sample – Professor Simon Crowe and colleagues measured the effect of stress and caffeine on 92 non-clinical participants.

Professor Crowe discovered that five coffees a day or more was found to be enough to increase the participant’s tendency to hallucinate.

‘High caffeine levels in association with high levels of stressful life events interacted to produce higher levels of hallucination in non-clinical participants, indication that further caution needs to be exercised with the use of this overtly safe drug,’ says Professor Crowe.

The participants were assigned to either a high or a low stress condition and a high or a low caffeine condition on the basis of self-report. The participants were then asked to listen to white noise and to report each time they heard Bing Crosby’s rendition of White Christmas during the white noise.

The song was never played. The results indicated that the interaction of stress and caffeine had a significant effect on the reported frequency of hearing the song. The participants with high levels of stress, or consumed high levels of caffeine, were more likely to hear the song.

‘There is a link between high levels of stress and psychosis, and caffeine was found to correlate with hallucination proneness. The combination of caffeine and stress affect the likelihood of an individual experiencing a psychosis-like symptom,’ says Professor Crowe.

This study also helped to explain the mechanism by which stress may facilitate the symptoms of schizophrenia in non-clinical samples. Caffeine has only recently been reported to increase proneness to hallucinate.

‘It is apparent that the health risks of excessive caffeine use must be addressed and caution should be raised with regards to the exacerbating use of this stimulant,’ says Professor Crowe.

To read more on this topic, and to find out more about what La Trobe University is up to, visit

Above picture courtesy of Daily Mail.