Studies Of The Effect Of Caffeine On The Human Brain

Caffeine is referred to as a stimulant of the central nervous system, but according to Lifehacker.com, it is more accurate to say caffeine acts to prevent inhibition of the brain's inherent stimulants, the neurotransmitters dopamine and glutamate. The lift provided by caffeine therefore has a different quality than that resulting from other stimulants. Research has also shed light on caffeine's effects on specific brain and behavioral conditions.

Addiction

A study published in the 2010 "Dialogues in Clinical Neuroscience" sought to evaluate the effects of caffeine on the human brain by tracking changes in blood flow in the brain in response to caffeine ingestion. The study used SPECT imaging and focused on areas of the brain associated with behavior reinforcement and reward, such as would be stimulated in chemical addictions such as nicotine or alcohol. A dosage level of 3 mg per kg of body weight was given to participants, and SPECT scans were done 45 minutes after consumption of the caffeine. The researchers reported caffeine affected areas of the brain involved in the control of vigilance, anxiety and cardiovascular regulation but did not affect areas of behavior reinforcement and reward, implying caffeine is not addictive.

Athletic Performance

Caffeine had no effect on the brain neurotransmitters serotonin and dopamine, according to a study published in the 2010 "Journal of the International Society of Sports Nutrition." The study, which sought to answer the question of how caffeine may improve short-duration, high-intensity exercise performance, gave caffeine both with and without high-fat meals to athletes before sessions of cycling. Levels of the neurotransmitters serotonin and dopamine were tested as an indication of changes in brain function during fatigue induced by athletic performance and were found to be unchanged. The researchers concluded glycogen depletion and not alterations in neurotransmitter levels were responsible for the observed effects.

Mental Alertness

A study published in the 2010 "Human Psychopharmacology" looked at the effects of caffeine and glucose on the ability to maintain attention in 40 human test subjects. Study participants were given 75 mg of caffeine, 75 mg of glucose and a combination of the two, and magnetic resonance imagining was used to assess activity levels of different areas of the brain while the subjects performed continuous performance tests. The researchers reported the best results were obtained from the combination of caffeine and glucose, in which the same level of performance was observed with less brain activation in areas of memory and attention, indicating a higher degree of efficiency.

Depression and Anxiety in Children and Adolescents

An investigation into the use of caffeine and its relationship to symptoms of depression and anxiety in fifth- and 10th-grade students was reported in a study published in the 2009 "Journal of School Health." The study reported depression but not anxiety was associated with caffeine use and this age group is vulnerable to increased depressive symptoms with increasing caffeine consumption.

Obsessive Compulsive Disorder

The effects of dextroamphetamine were compared with caffeine for the treatment of obsessive compulsive disorder in a study published in the 2009 "Journal of Clinical Psychiatry." After five weeks of treatment, participants' response was measured on a rating scale for obsessive compulsive disorder. The researchers reported dextroamphetamine users had a 48 percent decrease in symptoms, while caffeine users had a 55 percent decrease.