Coffee Makes People Nervous

They did not work with people; instead they examined rats of two lines. The rats of the first line were more anxious by their nature. Some rats were kept in groups, while others were kept in single cages. It is known that solitude is an unfavourable factor for rats.

The animals were given 0.1% solution of caffeine when they were thirsty. To measure the anxiety level the researchers examined the behaviour of animals in a cage with two sections: light and dark. More time the animal spends in the light section, more anxious it is.

The results of the experiment have shown that initially the rats of the anxious group living alone were more sensitive to caffeine, but after some period of regular caffeine consumption, they became tolerant to it. On the opposite, the rats of a calm group became more nervous after regular coffee drinking. However, despite their response to caffeine the animals did not become caffeine-dependent. The level of anxiety remained unchanged when animals stop to receive caffeine.

The Russian scientists suppose that a regular daily consumption of caffeine in coffee, tea or chocolate affects the human nervous system in a similar way.

Russian Foundation for Basic Research has supported this work.