HealthyNCT00487227
Effects of Low Doses of Caffeine on Mood, Physiology and Mental Function
A study testing caffeine in people with Healthy, run by Northumbria University.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- caffeine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 20 participants
- Where
- No sites listed yet
- Study dates
- Jun 2005to Nov 2005
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- native English speaker
Who cannot join
- pregnancy
- medication
- anaemia
- heart disorder
- diabetes
- respiratory disorder
Show all 11Show fewer
- epilepsy
- asthma
- panic attacks
- habitual smoking
- food allergy
About this study
Official title: 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.
Read the detailed description
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, standard deviation 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.
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
caffeineDrug
PlaceboDrug
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | Not described Receives: Drug: Placebo |
| 2.5mg caffeine | Experimental | Not described Receives: Drug: caffeine |
| 5mg caffeine | Experimental | Not described Receives: Drug: caffeine |
| 10mg caffeine | Experimental | Not described Receives: Drug: caffeine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from baseline speed of attention
Measured: 1 hour
Change from baseline speed of attention
Measured: 3 hours
Change from baseline speed of attention
Measured: 6 hours
Change from baseline speed of attention
Measured: 9 hours
Secondary outcomes (24)
Change from baseline accuracy of attention
Measured: 1 hour
Change from baseline accuracy of attention
Measured: 3 hours
Change from baseline accuracy of attention
Measured: 6 hours
Change from baseline accuracy of attention
Measured: 9 hours
Change from baseline speed of memory
Measured: 1 hour
Change from baseline speed of memory
Measured: 3 hours
Change from baseline accuracy of memory
Measured: 6 hours
Change from baseline accuracy of memory
Measured: 9 hours
Change from baseline subjective mood
Measured: 1 hour
Change from baseline subjective mood
Measured: 3 hours
Change from baseline subjective mood
Measured: 6 hours
Change from baseline subjective mood
Measured: 9 hours
Change from baseline blood pressure
Measured: 1 hour
Change from baseline blood pressure
Measured: 3 hours
Change from baseline blood pressure
Measured: 6 hours
Change from baseline blood pressure
Measured: 9 hours
Change from baseline heart rate
Measured: 1 hour
Change from baseline heart rate
Measured: 3 hours
Change from baseline heart rate
Measured: 6 hours
Change from baseline heart rate
Measured: 9 hours
Change from baseline salivary caffeine levels
Measured: 1 hour
Change from baseline salivary caffeine levels
Measured: 3 hours
Change from baseline salivary caffeine levels
Measured: 6 hours
Change from baseline salivary caffeine levels
Measured: 9 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Jun 2007 (estimated)
- Study startJun 2005
- Study completionNov 2005
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Northumbria University
- Sponsor type
- University, hospital or other
- Investigators
- Andrew Scholey, Principal investigator, Northumbria University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00487227
- Sponsor's protocol ID
- 7G2CDCH
- Status last verified
- Oct 2015
- First submitted
- 15 Jun 2007
- Last updated
- 8 Oct 2015
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 8 Oct 2015. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Levels of Caffeine Lower Than Those Found in Decaffeinated Beverages Exert Effects on Cognition, Mood, and Autonomic Activity
- ClinicalTrials.gov ID
- NCT00487227
- Acronym / sponsor ID
- 7G2CDCH
- Conditions
- Healthy
- Keywords
- caffeine, coffee, decaffeinated, cognition, mood, autonomic
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Northumbria UniversityUniversity, hospital or other
- Study start
- Jun 2005
- Study completion
- Nov 2005 (actual)
- First posted
- 18 Jun 2007 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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, standard deviation 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.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Drug: Placebo |
| 2.5mg caffeine | Experimental | Drug: caffeine |
| 5mg caffeine | Experimental | Drug: caffeine |
| 10mg caffeine | Experimental | Drug: caffeine |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- native English speaker
Key exclusion criteria (11 listed)
- pregnancy
- medication
- anaemia
- heart disorder
- diabetes
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| caffeine | Drug | 10mg caffeine, 2.5mg caffeine, 5mg caffeine |
| Placebo | Drug | Placebo |
Primary outcome
Change from baseline speed of attention
Time frame: 1 hour
Change from baseline speed of attention
Time frame: 3 hours
Change from baseline speed of attention
Time frame: 6 hours
Change from baseline speed of attention
Time frame: 9 hours
24 secondary outcomes
Change from baseline accuracy of attention
Time frame: 1 hour
Change from baseline accuracy of attention
Time frame: 3 hours
Change from baseline accuracy of attention
Time frame: 6 hours
Change from baseline accuracy of attention
Time frame: 9 hours
Change from baseline speed of memory
Time frame: 1 hour
Change from baseline speed of memory
Time frame: 3 hours
Change from baseline accuracy of memory
Time frame: 6 hours
Change from baseline accuracy of memory
Time frame: 9 hours
Change from baseline subjective mood
Time frame: 1 hour
Change from baseline subjective mood
Time frame: 3 hours
Change from baseline subjective mood
Time frame: 6 hours
Change from baseline subjective mood
Time frame: 9 hours
Change from baseline blood pressure
Time frame: 1 hour
Change from baseline blood pressure
Time frame: 3 hours
Change from baseline blood pressure
Time frame: 6 hours
Change from baseline blood pressure
Time frame: 9 hours
Change from baseline heart rate
Time frame: 1 hour
Change from baseline heart rate
Time frame: 3 hours
Change from baseline heart rate
Time frame: 6 hours
Change from baseline heart rate
Time frame: 9 hours
Change from baseline salivary caffeine levels
Time frame: 1 hour
Change from baseline salivary caffeine levels
Time frame: 3 hours
Change from baseline salivary caffeine levels
Time frame: 6 hours
Change from baseline salivary caffeine levels
Time frame: 9 hours
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Oct 2015.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Andrew Scholey principal investigator
Northumbria University
Questions about this trial
What is this clinical trial studying?
A study testing caffeine in people with Healthy, run by Northumbria University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 8 Oct 2015. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change from baseline speed of attention (time frame: 1 hour). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Oct 2015; AzTrials last refreshed its copy on 8 Nov 2026.