A very old friend of mine from university had to give up coffee when he was in his mid twenties. Much to his disgust, I might add, as he loved the stuff.

The reason he explained to me over a cup of green tea that a couple of cups of coffee would first make him anxious , then bad tempered and finally what he called a “brown study”. Nothing to worry about (he did mention it to his doctor at his next wish and was told that he was indeed correct).

The conversation came back to me this afternoon as I read a very interesting report from the The Institute for Scientific Information on Coffee on the relationship between coffee and anxiety. They define anxiety as “a feeling of nervousness, dread, apprehension, and worry. Mild anxiety is vague and unsettling, while severe anxiety can be extremely debilitating and considered a disorder”.

They say “… the body of scientific evidence to date suggests that caffeine may be associated with an increase in anxiety at moderate levels of intake (150mg caffeine – approximately two cups of coffee) in individuals who are predisposed to this effect, and that symptoms of anxiety are less likely to be seen at lower levels of caffeine intake. It is thought that the adenosine receptor system, which mediates the psychoactive effects of caffeine, is involved in the regulation of anxiety, although the precise mechanism is unknown at present”

In the report they point out that “caffeine seems to have no effect on anxiety in some individuals whilst in others, particularly at moderate (150mg caffeine) levels of intake, caffeine may increase anxiety” and “in high and low anxiety sensitive individuals, similar alertness and symptom reports were shown following caffeine ingestion. Respiratory symptoms were more marked when caffeine was expected and administered in the low anxiety sensitive group and when caffeine was unexpectedly administered in the high anxiety sensitive group”

They conclude “research suggests that there may be a genetic component to this sensitivity, explaining why only some individuals appear to experience an effect, however further research is required to confirm these effects.3 It is worth noting that with frequent consumption, substantial tolerance develops to the anxiety-inducing effect of caffeine, even in genetically susceptible individuals, and therefore the association does not tend to affect levels of coffee consumption”.

Which all seems pretty reasonable to me. What do you think? What impact does coffee have upon you? Please share in the comments section below.

Thanks in advance.