Drug FAQs

How long after an alcoholic drink does the alcohol reach the brain?

The first wave of alcohol reaches the brain within 30 seconds of having an alcoholic drink. Alcohol is very soluble in water, so it's quickly absorbed by the body into the bloodstream and can then easily pass into the brain. The amount of alcohol in the blood reaches a maximum about 20-30 minutes after having a drink.

When you have a drink, the alcohol passes through your mouth and oesophagus before entering the stomach and then the small intestine. although alcohol can be absorbed anywhere along this route, it's the stomach and small intestine that are the most important. About a quarter of the alcohol is absorbed in the stomach and the rest in the small intestine.

Many factors can alter the rate of alcohol absorption. If you have eaten a heavy meal, the release of the stomach contents to the small intestine slows down, delaying alcohol absorption. Stronger alcoholic drinks tend to be absorbed more quickly, though very strong drinks may slow the process. Fizzy drinks, like champagne, can get you drunk quicker, since the carbon dioxide they contain may speed up the drink's passage from the stomach to the small intestine.

Why are so many drugs addictive?

A person is addicted to a drug if they experience insatiable cravings for the substance and an impaired ability to control its use, even if it's causing them harm.

Drugs have powerful effects because they are similar to naturally occurring chemicals in our body. Many drugs, including alcohol, nicotine, tranquillisers, cocaine and opiates such as morphine and heroin produce both physical and psychological dependence. Their prolonged use alters the chemical balance in the brain and if their use is stopped, the body suffers withdrawal symptoms.

Scientists think that although these drugs may operate by different mechanisms, they all fundamentally affect the reward pathways in the brain. It's important that the body learns that some activities are pleasurable, such as eating, drinking and sex. When these activities are performed, the reward centres are stimulated by an increase in some brain chemicals, one of which is dopamine.

Drugs can increase the level of dopamine in the brain, either by actively increasing its release or by preventing it from being reabsorbed. These artificially raised dopamine levels strongly stimulate the reward pathways, and the user 'learns' to like the drug.

Are some people more at risk of becoming addicted to drugs than others?

Not all people who take potentially addictive substances will become addicted. Many people drink alcohol regularly but remain 'social drinkers' rather than becoming alcoholics. People in hospital may receive morphine injections and although they may become physically dependent on the drug, they are not addicted. They do not experience the severe out of control cravings that characterise addiction.

A person's state of mind, their social environment and genetic make-up are all factors that influence addiction. Long-term depression or stress may make a drug user more liable to addiction. A person trying heroin with a group of friends will have different expectations about what the drug will do for them than someone taking it for pain relief. A child with alcoholic parents is more likely to become an alcoholic themselves.

There are also possible biological reasons for addiction. People vary in the amount chemical messengers involved in stimulating the reward pathways in the brain. A naturally low level of these may increase susceptibility to the artificial boost offered by drugs.

How does caffeine keep you awake?

Caffeine, found in coffee, tea, some soft drinks such as cola, and in smaller amounts in chocolate, interferes with the chemistry of the brain by blocking a naturally occurring chemical that slows down brain activity.

The longer you are awake, the greater the amount of the chemical adenosine produced in the brain. As adenosine levels increase they bind to receptor sites in the brain and reduce the level of nerve cell activity. This causes feelings of drowsiness and eventually the body is overtaken by sleep. As you sleep, the level of adenosine gradually falls again.

Caffeine interferes with this cycle by binding to the sites in the brain intended for adenosine. Because the adenosine can't reach its receptors, the brain's nerve cells continue functioning at their usual levels and any feelings of drowsiness are forestalled, at least for a while.

How is drug use tested for?

Drugs can be tested for in various ways, including blood, urine and hair analysis. The body breaks down drugs in different ways, so specific methods are more appropriate for specific drugs. The time it takes for all traces of a drug to be eliminated from the body also varies – some may last for months.

When you take a drug, your body will start to remove it by breaking it down into other chemicals, called metabolites. These are then excreted from the body and can be detected in urine, saliva or even sweat. Drug tests search for the characteristic metabolites of specific drugs. As metabolites may remain in the body long after the effect of the drug has gone, recreational drug use is easy to detect.

Some drugs and their metabolites only last for a short time in the body and are gone within a day or so, such as cocaine, heroin and amphetamine-based drugs, like speed and ecstasy. Cannabis takes longer, perhaps up to eight weeks or more, because the metabolites are not very water soluble.

A newer method involves testing for the presence of drug metabolites deposited in the hair shaft. Because the hair grows slowly, a sample will provide a record of the past few months' drug use.

Drug testing is not without its flaws, as other substances which are perfectly legal, such as over-the-counter or prescription medicines, may also give positive results.

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