Previous investigations have determined that some individuals have minimal or even ergolytic performance effects after caffeine ingestion. The aim of this study was to analyze the influence of the genetic variations of the CYP1A2 gene on the performance enhancement effects of ingesting a moderate dose of caffeine. In a double-blind randomized experimental design, 21 healthy active participants (29.3 ± 7.7 years) ingested 3 mg of caffeine per kg of body mass or a placebo in testing sessions separated by one week. Performance in the 30 s Wingate test, visual attention, and side effects were evaluated. DNA was obtained from whole blood samples and the CYP1A2 polymorphism was analyzed (rs762551). We obtained two groups: AA homozygotes (n = 5) and C-allele carriers (n = 16). Caffeine ingestion increased peak power (682 ± 140 vs. 667 ± 137 W; p = 0.008) and mean power during the Wingate test (527 ± 111 vs. 518 ± 111 W; p < 0.001) with no differences between AA homozygotes and C-allele carriers (p > 0.05). Reaction times were similar between caffeine and placebo conditions (276 ± 31 vs. 269 ± 71 milliseconds; p = 0.681) with no differences between AA homozygotes and C-allele carriers. However, 31.3% of the C-allele carriers reported increased nervousness after caffeine ingestion, while none of the AA homozygotes perceived this side effect. Genetic variations of the CYP1A2 polymorphism did not affect the ergogenic effects and drawbacks derived from the ingestion of a moderate dose of caffeine.

Background: Although there is a growing interest in the role of attentional biases in depression, there are no studies assessing changes in these biases after psychotherapeutic interventions. Methods:We used a validated eye-tracking procedure to assess pre-post therapy changes in attentional biases towards emotional information (i.e., happy, sad and angry faces) when presented with neutral information (i.e., neutral faces). The sample consisted of 75 participants with major depression or dysthymia. Participants were blindly assigned to one of two 10 weekly sessions of group therapy: a CBT intervention (N=41) and a Positive Psychology Intervention (N=34).Results: Both treatments were equally efficacious in improving depressive symptoms (p = .0001, η² = .68). A significant change in attentional performance after therapy was observed irrespective of the intervention modality. Comparison of pre-post attentional measures revealed a significant reduction in the total time of fixations (TTF) looking at negative information (i.e., sad and angry faces) and a significant increase in the TTF looking at positive information (i.e., happy faces) -all p-values >.02. Conclusions:Findings reveal for the first time that psychotherapeutic interventions are associated with a significant change in attentional biases as assessed by a direct measure of attention. Furthermore, these changes seem to operate in the same direction typically found in healthy populations (i.e., a bias away from negative information and a parallel bias towards positive information). These findings illustrate the importance of considering attentional biases as clinical markers of depression and suggest the viability of modifying these biases as a potential tool for clinical change.

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