Drugs and the brain

Martin Barnes of DrugScope and neuroscientist Professor David Nutt explain the results of research into the effects of recreational drugs on the brain.

Acid (LSD) and magic mushrooms

Short term: Acid and magic mushrooms are hallucinogenic, making people see, hear and experience the world in a different, ‘trippy’ way. Colours may become intensified and sounds distorted. Users may also become panicky and suffer from paranoia. The effects of acid can last 12 hours or more which, if it’s a bad trip, can be very frightening.

Long term: Some LSD users experience flashbacks. "Sometimes people may experience psychosis or paranoia, believing or seeing things that aren’t really there," says Barnes.

Cannabis (marijuana, weed, dope, skunk)

Short term: People smoke cannabis to relax and get high, but it can make it difficult to remember things, even if they’ve only just happened. It can cause anxiety attacks or feelings of paranoia. "If you use a lot of cannabis regularly, you’re putting yourself at risk of some temporary problems, such as confusion or delusions," says Barnes.

Long term: "It’s possible that cannabis might trigger long-term mental health problems, including psychosis, schizophrenia and depression," says Barnes. "Evidence suggests that cannabis users who come from a family with a history of mental health problems may be particularly susceptible to these symptoms.”

Cocaine and crack cocaine

Short term: Cocaine is a stimulant that makes you feel high, confident and full of energy. But this can turn into feelings of anxiety, panic and paranoia. Users of cocaine can end up feeling tired and depressed.

Long term: Giving up cocaine and crack can be mentally distressing and physically difficult for dependent users. Long-term use can worsen existing mental health problems and lead to depression, anxiety and paranoia.

Ecstasy (E)

Short term: Ecstasy is a stimulant with hallucinogenic effects that makes you feel relaxed, high, ‘loved-up’ and ready to dance all night. But people who are already feeling anxious or who take high doses can have bad experiences of paranoia or feeling 'out of it'.

Long term: Regular use may lead to sleep problems, lack of energy, drastic weight loss, depression or anxiety. People can become psychologically dependent on the feelings of euphoria and calmness that ecstasy gives them. Research shows that taking ecstasy can reduce a user’s serotonin levels, and may have an effect on certain areas of the brain.

Heroin (smack, diamorphine)

Short term: Heroin and other opiates slow down the body’s functions and stop both physical and emotional pain. Users find they need to take more and more herion to get the same effect, or even feel ‘normal’. Taking a lot can lead to coma or even death.

Long term: Heroin is psychologically and physically highly addictive. "The withdrawal from heroin is really unpleasant," says Professor Nutt. "Long-term heroin users are often depressed because of their overall lifestyle." Coming off and staying off heroin can be very difficult.

Ketamine (K)

Short term: Ketamine is an anaesthetic that makes people feel relaxed and high, but its effects are unpredictable. "It’s like drinking a whole bottle of vodka: you don’t have any control over what you’re doing," says Professor Nutt. "The biggest danger is wandering off in a daze and having an accident or getting lost and staying out all night, resulting in hypothermia." Ketamine can make you feel detached from yourself and others, and make existing mental health problems worse.

Long term: Tolerance develops quickly so people need more K to get high. "The longer term effects are more difficult to pinpoint, but may include flashbacks and losing your memory and ability to concentrate," says Barnes. "Occasionally, people get psychotic symptoms, while evidence is growing that long-term use of ketamine can severely damage the bladder. Some people find it hard to stop taking K."

Solvents (gases, glues and aerosols)

Short term: Solvents make you feel drunk and sometimes cause hallucinations.

Long term: Heavy use of solvents poisons your brain and can damage it, making it hard to control your emotions, think straight or remember things.

Speed and crystal meth (amphetamine and methamphetamine)

Short term: Speed can quickly make you feel energetic and confident but, with the high, can come panic, irritability and a paranoid sense that everyone is looking at you. Smoking a version of speed called methamphetamine (crystal meth) can give an intense and prolonged high but a severe comedown, when feelings of hopelessness and sadness are common.

Long term: There’s no research on the long-term heavy use of speed. Professor Nutt has seen users, especially those who have injected speed regularly, who appear to be permanently depressed. They have difficulty thinking straight, remembering things, problem solving and coping with their emotions.


Short term: Steroids pump up muscle mass but can bring on ‘roid rage’, with users becoming physically violent and sexually abusive. Steroids can make sleep difficult and cause confusion, depression and paranoia.

Long term: They can lead to psychological dependence, where people become convinced they cannot perform well without the drug.

Tranquillisers (benzodiazepines)

Short term: Tranquillisers such as Valium are sedative drugs. They are used to relieve anxiety and aid sleep. Some drug users take them to help a comedown from drugs such as cocaine or speed.

Long term: The body quickly gets used to benzodiazepines and soon needs more to get the same effect. It’s possible to become addicted in just a few weeks and withdrawal can be difficult and make people feel sick, unable to sleep and very anxious. Sudden withdrawal from high doses can be very dangerous and result in serious convulsions (fits).

Further information about the effects of drugs

Page last reviewed: 09/10/2014

Next review due: 09/10/2016


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The 8 comments posted are personal views. Any information they give has not been checked and may not be accurate.

generic drugs said on 10 October 2011

<a href="http://www.medsearchonline.com/">Generic drugs</a> should be taken in controlled doses according to doctor’s prescription so that the side effects can be avoided.The prescription should be followed carefully so as to produce better results.

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boogienights said on 11 July 2010

There are many million more deaths every year from 'legal' drugs i.e. alcohol, cigarettes. Than there has ever been from illegal drug, legalize these recreational drugs such as ectastcy, then the correct chemicals will be used instead of the dangerous, cheaper crap that are put in them (that can cause life-threatening conditions), also the drug barons who drive around in their fancy cars and live a fantastic lifestyle from selling their posion, would be eradicated hooray! Come on the British government wake up and smell the coffee, your never gonna stop it so legalise it and make it safe. (Just think of the all the tax revenue to be made surely that's an incentive 4 our government!) We are constantly being brain washed by the uk government, M.Cat has been banned because 2 young lads died after taking it......... what they didn't tell us until about a month later (surely they would have known by the following day) that these two lads hadn't even taken any M-Cat after all by this time they had got it through parliment and it had been made illegal????!!!!!!!!

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pinkcorset said on 04 March 2010

people that put drugs in others drinks should think what they are doing before they do it. It isnt funny and its cruel and you should be imprisoned where you belong. I nearly died because of the effects of someone else doing drugs.

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Alkitra said on 13 February 2009

Listen to what the User52480 said! Don't try it at all! Even cigarettes, don't matter if it upsets your mates. It will save you money, regret and most importantly, health... not that I'm being a hypocrite here because I smoke myself too, but I regret ever trying it. Learning my lesson, I'll never touch any illegal drugs cocaine, crack, you name it... I tried weed but I don't like it anyway:-)

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janeita said on 07 February 2009

This is really useful information! Many drug addicts do not even know that drugs have these negative effects on their bodies.

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User52480 said on 15 October 2008

I tell you what, just do not take it at all, we have to finde an other way to have fun or relax cheel out however it is call.

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razzle69 said on 05 July 2008

drugs are bad...ok.

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Oche said on 28 June 2008

You know what?
It would be great if there was even the slightest bit of empirical data to compare the dangers of all of the above illicit drugs and alcohol across a spectrum of effects. I wonder if it is even possible to compare the dangers of these substances accurately at this point in time?

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