Caffeine & Alcohol


The use of caffeine is very common. All over the world people wake up and start the day with a cup of tea or coffee to help them with a little get-up-and-go. How does caffeine do this? For people who respond to caffeine (and not everyone does) it can reduce the perception of pain (useful if you find getting out of bed hard), increase alertness, improve memory and cognition and reduce feelings of boredom and fatigue. Pretty positive so far! However, if consumed in quantities that are too high it can increase feelings of anxiety and nervousness, and can cause shaking and insomnia. Not so positive. Just the insomnia alone will be likely to have a negative impact on mood. This will also of course leave you feeling fatigued which can in turn leave you reaching for a cup of coffee to reverse this feeling and the whole cycle begins again. Caffeine has a long half-life, which means that it can take up to a couple of weeks to break down completely and leave your system. So if you are having 2-3 cups a day, plus the odd bit of chocolate, can of Coke, cup of tea etc then it’s easy to see how caffeine levels can build up in your system.

Caffeine withdrawal can also have a horrible effect on mood. Irritability, difficulty concentrating and headaches are all common when people don’t get the caffeine that they are used to. If any of this sounds familiar to you then having a couple of weeks’ break from caffeine might be a good idea.


Alcohol can affect mood in several ways. When you’re slightly tipsy it can be a mood lifter, reduce inhibitions and help to take focus away from the worries of the day. However, if you go beyond this it can go completely the other way.

And then there’s the hangover.

Alcohol is often called a depressant. This doesn’t mean necessarily that it makes you depressed (although heavy alcohol use and clinical depression have very strong links), but rather that it depresses some chemical action in the brain. Glutamate, a neurotransmitter associated with increased brain activity, is suppressed by alcohol making our brain slow down a bit and this is probably where that relaxed feeling comes from. But alcohol is also a stimulant in that it increases production of other neurotransmitters such as GABA, which is involved with slowing everything down in the brain. So the reduction in excitatory chemicals and the increase in inhibitory chemicals means you have a double whammy and why slurred speech and being wobbly happen when you are drunk. Of course alcohol can make us feel happier because it increases dopamine levels, a neurotransmitter associated with pleasure and reward.

So after a few drinks you feel relaxed but after a few more, brain chemistry can get a bit off balance. This can lead to exaggerated emotions (blowing things out of proportion), aggression, loss of inhibitions (including about eating: how often do you feel good afterwards about getting a doner kebab?), short-term memory loss and injuries.

The morning after is the next thing. No one really knows what causes a hangover and, apart from not drinking in the first place, no one really knows how to prevent or cure one. What we do know is that when you are hungover you feel awful and if you are prone to comfort eating then a hangover is very likely to drive you to whatever makes you feel good. This can lead to a feeling of guilt or regret at having consumed a whole 12” stuffed-crust pizza. In summary, alcohol and mood are closely linked.