People who suffer from Alexithymia - or an inability to identify or describe feelings - are twice as likely to consume coffee and other caffeine products than those without the emotional disorder, according to new research.
Bond University Associate Professor Dr Michael Lyvers conducted a survey of 106 Bond University students aged 18-30 over six months and found those who reported Alexithymia consumed twice as much caffeine daily compared to their peers.
Dr Lyvers' previous research has linked Alexithymia to higher alcohol consumption and cannabis use, but Dr Lyvers said he was surprised to find such a strong correlation with caffeine.
"Alcohol is a relaxant, whereas coffee and other caffeine products in high doses act as stimulants and can therefore aggravate anxiety and stress - so it's surprising that people who exhibit these symptoms have higher consumption levels than others," he said.
"Alexithymia might be a little-known affliction but it is estimated that about 13 to 17 per cent of the population meets the criteria for the disorder.
"What this study tells us is that people with Alexithymia, a condition often characterised by high stress and anxiety levels, tend to use caffeine more than their peers, even though consumption may actually be counter-productive.
Dr Lyvers' research was conducted using the Toronto Alexithymia Scale 20 (TAS-2) - a self-report questionnaire which has been validated by previous research.
The students were also required to keep a record of all caffeine intake via food and beverages.
Dr Lyvers said it was important for people to understand the impact different substances could have on their emotional state.
"While most people readily identify alcohol and cannabis as drugs, most people don't think of caffeine as a substance which could have a real impact on the way they act and feel," he said.
"When consumed In small to moderate doses, caffeine has a negligible impact, but those who have an intake over and above recommended daily requirements may be exacerbating symptoms of stress and anxiety."