Caffeine is the most widely used psychotropic drug in the world. Surely, most of us consume caffeine on a regular basis (or if not, have done so at some point in our lives). But, do we know what the psychological effects of caffeine really are?

In this article we will try to answer this question, through a review of recent scientific literature. We will see how its main effects are produced in: convergent thinking (problem solving) and improvement in attention and concentration.

What is caffeine?

Before going into the psychological effects of caffeine, let’s see what exactly this substance consists of. Caffeine, as most of us will know, is mainly found in coffee; it is an alkaloid of the xanthine group, which acts as a psychoactive drug . Caffeine is absorbed and quickly passes to our brain; thus, it does not accumulate in the blood nor is it stored in any part of the body. It is excreted through the urine.

The main effect of caffeine on our brain is the stimulation and/or excitation of the central nervous system , through a non-selective antagonistic mechanism of adenosine receptors. It is for this reason that many people consume caffeine to combat fatigue or short-term sleepiness. In addition, caffeine also acts as a diuretic substance (helps our body eliminate fluid).

Where does caffeine come from? Mainly from certain types of plants, although it can also be synthesized artificially.

Psychological effects of caffeine

What are the psychological effects of caffeine? To answer this question, let’s look at a recent study that analyzes its effects on different cognitive processes.

As we have seen, caffeine is a psychotropic drug; specifically, the most consumed in the world . The main psychological effects of caffeine are: increased alertness and vigilance, improved mood and improved concentration and attention. Some studies even speak of a possible effect of caffeine on creative thinking.

1. Concentration and attention

The results of the study that we are going to analyze (Zabelina & Silvia, 2020), show how the consumption of caffeine produces a greater concentration and attention.

This study used a randomized, double-blind, placebo-controlled design among subjects who consumed 200 mg of caffeine (approximately one large cup of American-style coffee) versus those who did not (placebo group).

The study focused on analyzing the effects of caffeine on two types of thinking: convergent thinking (problem solving) and divergent or creative thinking (generation of creative ideas).

On a general level, the psychological effects of caffeine shown in this study are that caffeine significantly improves problem solving, although its effects on the generation of creative ideas and/or working memory are not as clear (no improvement), as we will see later.

In addition, it is worth mentioning that the study controlled the expectations of the participants so that their belief of having consumed or not consuming caffeine, did not alter the results .

2. Problem solving

The above-mentioned study (Zabelina & Silva, 2020) showed how caffeine consumption (200 mg), was associated with better results in problem solving (specifically, faster resolution). This, in turn, was related to an improvement in the speed of information processing .

The psychological effects of caffeine expressed in this study are in line with those of previous studies such as the research of Rao et al.

Furthermore, these studies also establish that caffeine consumption is related to improved problem solving (at a general level, regardless of whether the approach is more analytical or more global) and other higher order cognitive processes (e.g. response inhibition).

The improvement of attention is specified, among others, in visual tasks that require the use of selective attention . These results are related to increased activity in the prefrontal area of the brain.

3. Creative thinking

Do the psychological effects of caffeine also apply to creative thinking? As for this type of thinking (also called divergent thinking), a priori, the above-mentioned study shows how caffeine did not affect the generation of creative ideas.

On the other hand, this type of thinking is known to be associated with increased alpha activity in the brain (related, in turn, to relaxation and network inhibition). Caffeine reduces alpha activity, so it would be expected that this substance would reduce the generation of divergent thinking .

However, the results are not clear, since another line of work reports complex interactions between “top-down” and “bottom-up” cognitive processes during divergent thinking.

Disparate results

As for the psychological effects of caffeine on creative or divergent thinking, it is not clear whether caffeine has any effect on it.

However, according to the study, the amount of caffeine administered to the participants (200 mg) may not be sufficient to have a relevant effect on the generation of ideas during divergent thinking. It is anticipated that larger amounts (e.g. 400 mg) would negatively affect this type of thinking, making it more difficult.

More or better creative ideas?

It is worth mentioning one fact, and that is that the test used to evaluate divergent thinking in Zabelina & Silva’s study (2020), called ATTA (battery of divergent thinking tasks), may reflect above all the number of creative ideas that people can generate, and not so much the quality of these ideas .

This deserves to be taken into account since it could “alter” the results, in the sense that the effects of caffeine would be null to generate many ideas, but that the few generated, could be very good.

Placebo effect in the study

In the Zabelina & Silva study, some participants did not take the caffeine capsule, but a placebo capsule.

Related to this, participants who consumed the caffeine capsule were seen to be equally likely to guess whether their capsule was caffeine or placebo (i.e., equally likely to be wrong); however, participants in the placebo capsule were more likely to be right (saying their capsule was placebo).

What’s so interesting about this? That these results are in line with what is said in previous literature on the subject (Griffiths et al., 1990), and that discrimination in this sense is reduced after consuming caffeine.

Bibliographic references:

  • Griffiths, R. R., Evans, S. M., Heishman, S. J., Preston, K. L., Sannerud, C. A., Wolf, B., & Woodson, P. P. (1990). Low-dose caffeine discrimination in humans. Journal of Pharmacology and Experimental Therapeutics, 252(3), 970-978.
  • Rao, A., Hu, H., & Nobre, A. C. (2005). The effects of combined cafeine and glucose drinks on attention in the human brain. Nutritional Neuroscience, 8(3), 141-153.
  • Zabelina, D. L., & Silvia, P. J. (en prensa). Percolando ideas: Los efectos de la cafeína en el pensamiento creativo y la resolución de problemas. Conciencia y Cognición.