Porcelain cup and coffeeCredit: Julian Cenkier


Carly Simon musically stated, “I had some dreams, they were clouds in my coffee.” Would Ms Simon be surprised to learn that actually coffee can cause clouds in reality?  Research conducted at La Trobe University by Professor Simon Crowe determined that consuming five cups of coffee a day was classified as heavy drinking. The research also determined that consuming that much caffeine could contribute to hallucinatory experiences.

What are Hallucinations?

The word hallucination comes from Latin and means "to wander mentally." Hallucinations are false perceptions that individuals can have that don’t really exist in reality. Hallucinatory experiences may involve individuals hearing, seeing or smelling things that are not there.

Hallucinations are usually associated with mental illness, but now it has been determined that heavy coffee consumption can contribute to hallucinatory experiences as well.

How Can Heavy Coffee Consumption Cause Hallucinations?

 Researchers from the School of Psychological Sciences at La Trobe University conducted a study to measure the effect of caffeine and stress on selected participants. The participants were categorized as either high or low stress or either high caffeine or low caffeine consumption. The category placement was determined by information gathered from participants’ own reports regarding  their stress and coffee consumption. The participants were then asked to listen to white noise. White noise is created by combining sounds of all different frequencies together. The participants were then expected to report each time they heard the song, a designated song.

The designated song was never actually played for any of the members of the study groups. However, the research results indicated that the interaction of stress and caffeine had a notable effect on the reported frequency of participants hearing the designated song.

Those participants who had greater stress levels or who drank more coffee or other forms of caffeine were more likely to report hearing the song. Quoting the findings of the lead researcher in the study, "The combination of caffeine and stress affect the likelihood of an individual experiencing a psychosis-like symptom."

In conclusion, it would appear that caffeine consumption, in moderation, can increase the capacity for mental or physical labor. That is, of course, a good effect. However, if caffeine is consumed excessively, the undesirable effects can be behaviors that seem almost like intoxication, Excessive consumption can also cause increased nervousness, irritability, and anxiety.  Insomnia, headaches, heart palpitations also seem to be undesirable effects of excessive consumption, and, as the new research indicates, hallucinations as well.


Porcelain cup and coffee
Credit: Julian Cenkier