Item Average caffeine content (mg)

Coffee (5 oz cup)

brewed drip method

115

brewed percolator

80

instant

65

decaffeinated, brewed

3

decaffeinated, instant

2

Tea

brewed (5 oz cup)

50

instant (5 oz cup)

30

iced (12 oz glass)

70

Cocoa beverage (5 oz cup)

4

Chocolate milk beverage (8 oz)

5

Milk chocolate (1 oz)

6

Dark chocolate, semi-sweet (1 oz)

20

Coca-Cola (12 oz)

45.6

Diet Coke

45.6

Pepsi Cola

38.4

Diet Pepsi

36

Pepsi Light

36

Some weight-control aids, alertness tablets and diuretics also contain significant amounts of caffeine.

Source: US Food and Drugs Administration.

Both caffeine and alcohol are listed as substances which produce substance-related mood disorders in the American Psychiatric Association’s Diagnostic and Statistical Manual (4th edition, 1994). It comes as a surprise to many people that caffeine can have the far-reaching effects it does. It has been shown to be associated with low birthweight for babies from high caffeine-consuming mothers and an increased risk of cardiac problems in high caffeine-consuming people; and of course it is known for its sleep-disturbance properties and the ‘jittery’ effect that many people have when they drink too much.

In summary, caffeine is one of those substances that is best taken strictly in moderation. There is some evidence that at such a level (around three cups of instant coffee per day) it has quite a good anti-depressant effect; much more and you really need to be cutting down, back to around that daily level of three cups.

If you are drinking an excessive amount of coffee (and I’ve come across people who drink thirty cups a day), the best way of cutting down is first of all to halve your current consumption. Then hold that level steady for a week or two. Then halve it again. Then hold that level for a week or two, and halve it again if necessary – keeping going until you get to around three cups a day.

You may well find it surprisingly difficult to cut back because, although most people don’t think they are addicted to the amount of caffeine they consume, you probably are. Common withdrawal symptoms include painful headaches and tiredness, although in total it appears that caffeine depletes your energy levels rather than boosts them. Some people who have headaches first thing in the morning or at weekends find that they are associated with caffeine withdrawal because, naturally enough, one doesn’t normally consume caffeine through the night and many people drink a lot more caffeine during the working week than at weekends.

In summary, then, limit yourself to around three cups of instant coffee or its equivalent each day. And even then, don’t have one of those in the evening time or it will probably interfere with your sleep.

Pretty much the same applies to alcohol. In moderation it’s fine, but in excess it really is troublesome.

Recommended weekly maxima in the UK are currently 21 units for men and 14 units for women, where a unit is roughly equivalent to a glass of wine, half a pint of beer or a measure of spirits. Current US recommendations are for a slightly lower intake; the Connecticut Clearinghouse (‘a program of Wheeler Clinic Inc., funded by the Department of Mental Health and Addictions Service’) says that ‘moderate drinking’ should not be exceeded, and defines ‘moderate’ intake as one drink a day for females and two drinks a day for males, where one drink is equivalent to 1.5 ounces of distilled spirit (80% proof), 5 ounces of wine or 12 ounces of regular beer.

Personally, although I confess to being rather fond of drinking, I expect that the UK maxima will be lowered in due course. Anyway, if you drink much more than this and also find yourself troubled by irritability, then you really need to work hard at getting down to these limits as a maximum.

The real problem with alcohol is that it interferes with your sleep. Contrary to popular belief, the chances are that your quality of sleep is actually impaired rather than improved by consuming alcohol. Obviously, taken in large amounts it leaves you hung over, and taken even in not very great amounts it still leaves you under par the next day, partly because it attacks your supply of B vitamins.

It’s no real answer, but if you are drinking too much alcohol and find it very difficult to cut it down to reasonable levels, then at least make sure that you take regular multivitamin supplements. Clearly this is not half as good as not damaging yourself in the first place, but it does go some way to undoing part of the damage.

ALCOHOL PROJECT

This one is clear and simple: get down to the recommended maxima of alcohol per week.

Obviously this is a very important one, not only because of the implications for your irritability, but also in terms of minimizing the damage alcohol does to your liver and brain especially.

If you can manage this by yourself, simply by starting up a new habit of drinking a lot less, then so much to the good. If you need some outside help, it’s worth getting it. Your family doctor might be able to recommend somebody, or you can get in touch with Alcoholics Anonymous (local contact numbers are in the phone book); you don’t have to be drinking as much as you think in order to get help from them.

Recreational (‘street’) drugs

This category covers a great many drugs, and I am not expert on any of them, so I don’t propose to say too much here. I would rather leave it to your own judgement. Given what we have said above about the ‘routine’ drugs of caffeine and alcohol and the damaging effects that they have been proved to inflict upon us, you can probably judge for yourself what effect other drugs might be having on you, if you are taking any, and what you had best do about it!

Sleep

The importance of sleep is very difficult to overstate. If you can get into the routine of having a good night’s sleep, then this will have a major impact on the quality of your mood. There are a number of rules, many of which have been mentioned already:

Get up at a regular time; the body likes routine.

Eat at regular times; again, the body likes routine.

Avoid too much caffeine (not more than around three cups of instant coffee per day) and too much alcohol (not more than three units per day if you are a man, two if you’re a woman).

Get a reasonable amount of physical and mental activity into your day; try to break the vicious circle of feeling tired, therefore not doing much, therefore not sleeping very well and therefore feeling tired . . .

Have a wind-down period before you go to bed; a low-activity routine so that you go to bed relaxed.

Make sure you’re neither too hungry nor too full when you go to bed.

Ensure that you have a regular bedtime; again, the body likes routine.

Some people find they are able to induce a state of happiness as they lie in bed; if you can do this it’s a good idea – happy people sleep better than unhappy ones!

Make sure you’ve got rid of any extraneous sudden noises from central heating or anything else, and that you are warm enough but not too hot.

Well, that isn’t exactly a fully comprehensive account of how to reform your sleeping habits, but it’s a fair start. If you really make sure that you are doing all of those, all at once, then you shouldn’t be sleeping too badly at all. Only one other thing; don’t try to sleep – even if you just lie there awake but relaxed all night your brain will go into a different mode and you’ll have a reasonable amount of rest, so long as you don’t actually harass yourself with trying to sleep.

SLEEP PROJECT

Regardless of whether you think of yourself as having sleep problems it is still an excellent idea to get as good a night’s sleep as possible. The importance of a good night’s sleep is very difficult to overestimate.

Therefore apply your mind to implementing as many of the above points as you can, including setting realistic times for bedtime and getting-up time in order to ensure that you have enough time in bed but not too much.

Of course, if you work shifts, this can be a tremendous problem. Some people seem to be able to manage shift work quite easily, others not. In either case do make sure that you get straight into the new routine as soon as your shift changes; the body isn’t normally too upset about occasional changes in the routine so long as you then stick to it for a substantial period of time. Other people simply cannot tolerate, for example, night-shift work. If you are one of those then you might have to take more radical measures like moving on to a job that doesn’t entail night-working.

Come what may, make sure you do everything in your power to get a good night’s sleep.