Caffeine Study Finds No Performance Enhancement

Cup of TeaCup of TeaA study published
this month in Neuropsychobiology has found that sustained caffeine use has no
significant enhancing effects on performance or mood and does not provide a
restorative effect after poor sleep. So are the approximately 90% of us who
feel we get a boost from caffeine, just deluding ourselves?

Research into caffeine has
produced mixed results. Previous studies have shown some associations between
caffeine intake and increased alertness, vigilance and lower levels of fatigue
– as we might expect. Even so, some researchers have found that the apparent
benefits of caffeine are only seen in individuals who already use the drug.
Those not already caffeine users show much smaller improvements. Other studies,
however, have found different patterns.
This study differs from many
previously carried out by controlling for the effects of caffeine withdrawal.
What it suggests is that these types of apparent enhancements are more the
result of the alleviation of caffeine withdrawal. Caffeine withdrawal has
already been recognised as a kind of disorder causing certain predictable
symptoms including drowsiness, headaches and negative mood. It is the
association in our minds between the alleviation of caffeine withdrawal
symptoms and our morning cup of coffee that keep us coming back for more.
What studies like this suggest
is that, overall, our cognitive functions are no more highly tuned if we use
drinks containing caffeine than if we abstain completely. In fact there was
some evidence found here that caffeine might actually be undermining the
restorative effects of sleep.
There has been evidence from
epidemiological studies of the long-term benefits of caffeine consumption –
such as protection from cancer – but these are, at best, fairly speculative.
Equally, caffeine does raise blood pressure and increase the risk of coronary
heart disease and strokes.
The findings of this study are
a blow to the perception that caffeinated drinks provide a boost to mental
performance. After all, most people don’t drink tea or coffee for the long-term
health benefits – they just want to wake up.
A word of warning to those
inspired to give up: breaking a habit as ingrained as drinking tea or coffee
can be difficult and it has been shown that a stepped approach is best. The
symptoms of complete caffeine withdrawal can last up to 7 days and are not
pleasant if experienced in one go. I know, I’ve tried it.
the author

Psychologist, Jeremy Dean, PhD
is the founder and author of PsyBlog. He holds a doctorate in psychology from
University College London and two other advanced degrees in psychology.
He has been writing about
scientific research on PsyBlog since 2004. He is also the author of the book
“Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks.
Kayode Ojo
Kayode Emmanuel Ojo is the Co-Founder and Managing Director at SHEFFA Limited. He is presently studying Computer Science at the National Open University, Victoria Island, Lagos.