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Effects of Low Doses of Caffeine on Mood, Physiology and Mental Function

This study has been completed.
Sponsor:
Information provided by:
Northumbria University
ClinicalTrials.gov Identifier:
NCT00487227
First received: June 15, 2007
Last updated: NA
Last verified: June 2007
History: No changes posted

June 15, 2007
June 15, 2007
June 2005
Not Provided
Assessment of memory, attention, reaction time and subjective mood, measurement of heart rate and blood pressure. Co-monitoring of salivary caffeine levels. [ Time Frame: baseline, 1 hour, 3 hours, 6 hours and 9 hours ]
Same as current
No Changes Posted
Not Provided
Not Provided
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Effects of Low Doses of Caffeine on Mood, Physiology and Mental Function
Levels of Caffeine Lower Than Those Found in Decaffeinated Beverages Exert Effects on Cognition, Mood, and Autonomic Activity

It is often assumed that levels of caffeine found in ‘decaffeinated’ beverages are below any psychopharmacological threshold. However, recent findings indicate that caffeine doses as low as 9 mg may be psychoactive. The effects of caffeine have also been shown up to 6 hours post-administration. The study aimed to establish the lowest active dose of caffeine, and to ascertain the duration of any effects.

The majority of recent caffeine studies have evaluated doses in the range of 75 – 150 mg or 1 – 2 mg/kg (approximately 130 - 260 ml fresh coffee). Such doses produce well characterised effects; including increased ‘alertness’, and improvements to measures of reaction time and sustained attention. A previous study has demonstrated improvements to performance following 9 mg caffeine, which represents the lowest known psychoactive dose of caffeine. A number of these effects, including elevated salivary caffeine levels, were still apparent at 6 hours post-caffeine consumption (9). Findings showing effects of 12.5 and 9 mg caffeine are important as these are approaching the levels found in decaffeinated beverages, which are assumed to have no behavioural or physiological effects. However, despite extensive research in this area, the lower threshold for psychoactive effects has not been established. A randomised, placebo-controlled, double-blind, balanced crossover study was undertaken. 20 young men and women (13 female, mean age 20.7 years, SD 2.4) undertook computerised assessments of memory and attention and rated subjective mood. Autonomic activity and salivary caffeine were co-monitored. Assessment took place at baseline, 1, 3, 6, and 9 hours post-administration of placebo, 2.5, 5, and 10 mg caffeine (on separate days) administered in 150 ml fruit juice.
Interventional
Not Provided
Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double-Blind
Primary Purpose: Basic Science
Healthy
Drug: caffeine
Not Provided
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
20
November 2005
Not Provided

Inclusion Criteria:

  • native English speaker

Exclusion Criteria:

  • pregnancy
  • medication
  • anaemia
  • heart disorder
  • diabetes
  • respiratory disorder
  • epilepsy
  • asthma
  • panic attacks
  • habitual smoking
  • food allergy
Both
18 Years to 35 Years
Yes
Contact information is only displayed when the study is recruiting subjects
Not Provided
 
NCT00487227
7G2CDCH
No
Not Provided
Northumbria University
Not Provided
Principal Investigator: Andrew Scholey Northumbria University
Northumbria University
June 2007

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP