Cognitive Abilities, Anxiety and stress
Conditions
Interventions
It is a randomized controlled triple-blind trial with two groups: caffeine and placebo
each group containing 30 participants. To the caffeine group, 150 mg of caffeine (in capsule) will be given orally, in the morning for 12 weeks. To the placebo group, 150 mg of pharmaceutical talc (in
Dietary supplement
SP6.051.227
Sponsors
Departamento de Biociências da Universidade Federal de São Paulo - Baixada Santista
Departamento de Biociências da Universidade Federal de São Paulo - Baixada Santista
Eligibility
Age
18 Years to 40 Years
Inclusion criteria
Inclusion criteria: healthy volunteers, both genders; age between 18 and 40 years; students of UNIFESP Baixada Santista; minimum of 11 years of school education.
Exclusion criteria
Exclusion criteria: psychiatric diagnoses; obesity; dyslipidemia; cardiopathy; gestation; intellectual, visual and auditory deficiency; HIV on antiretroviral therapy; cirrhosis; renal failure.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Expected outcome 1 - An inverted U-shaped quadratic curve in cognitive variables (Rey Auditory Verbal-Learning Test, Stroop Test, Digit Span, Verbal and Semantic Fluency)on caffeine group, using repeated measures ANOVA, considering estatiscally significant P<0,05.;Outcome found 1- the groups did not present a statistically significant difference in the performance of the cognitive tests (Rey Auditory Verbal-Learning Test, Digit Span, and Verbal and Semantic Fluency Test), except for the Stroop Test, that presented significant difference between the groups - Stroop interference index (5.03, 95% CI, 1.67 to 8.39, P = 0.004). The effect size assessed by partial square eta (?²) was 0.136. ;Expected outcome 2 – the difference in performance in the Spielberger State Anxiety Inventory will not be statistically significant between groups, repeated measures ANOVA.;Outcome found 2 – there was no difference in performance in the Spielberger State Anxiety Inventory between groups (P=0,388). | — |
Secondary
| Measure | Time frame |
|---|---|
| Expected outcome 1 - the difference in performance in the Perceived Stress Scale will not be statistically significant between the groups, repeated measures ANOVA.;Outcome found 1 – there was no estatistically significant difference between groups on Perceived Stress Scale (P=0,232).;Expected outcome 2 - the association between baseline caffeine intake and anxiety assessed through the Trait Anxiety Inventory will be poor, Pearson's correlation test.;Outcome found 2 - the association between baseline caffeine intake and anxiety assessed through the Trait Anxiety Inventory was poor and negative, R=-0,211.;Expected outcome 3 - performance in cognitive tests (Rey Auditory-Verbal Learning Test, Stroop Test, Digit Extension Test and Verbal and Semantic Testing) will be similar regardless of the caffeine consumption category (low, moderate and high), one-way ANOVA, Bonferroni post-hoc test, DMS post-hoc test.;Outcome found 3 - There was no statistically significant difference between the categories of caffeine consumption (low, moderate and high) in the performance of most of the cognitive tests (Rey's Auditory-Verbal Learning Test, using the variable SUM A1-A5, P = 0.696; Digit Span, direct order, P = 0.122; Digit Span, inverse order, P = 0.295; Verbal and Semantic Fluency Test, semantic fluency, P = 0.669; Verbal and Semantic Fluency Testing, fluency verbal and semantic, P = 0.422). In the Stroop test, using the variable Stroop Interference Index, there was a significant difference (P = 0.035) between the moderate and high categories (Bonferroni post-hoc test, P = 0.030), better in high categories. In the Verbal and Semantic Fluency Test, variable verbal, there was a statistically significant difference (P = 0.017) between the low and moderate categories (post-hoc DMS test, P = 0.018) and between the low and high categories (post-hoc DMS test, P = 0.046), better in low categories. | — |
Countries
Brazil
Contacts
Public ContactKarina Faria de Souza
Departamento de Biociências da Universidade Federal de São Paulo - Baixada Santista
Outcome results
None listed