this was taken from an nhs web site not very offical in someways they can't prove alot of it.
Drugs on the brain
Experts are constantly researching the effects of recreational drugs on the brain, from paranoia to depression. Martin Barnes, of independent charity DrugScope, explains what they've discovered.
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 ‘is-everyone-looking-at-me’ paranoia. 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 but Professor David Nutt of the psychopharmacology department of Bristol University 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.
Valium (tranquillisers, benzodiazepines)
Short term: valium is a sedative and may be taken to relax or 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).
Marijuana, weed, dope, skunk (cannabis)
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. "If you or someone in your family has mental health problems, it’s best to avoid cannabis altogether."
Cocaine and crack cocaine
Short term: coke makes you feel high, confident and full of energy but this can tip over into feeling anxious, panicky and paranoid. People can feel tired and depressed after taking coke and excessive use can trigger paranoia.
Long term: giving up coke and crack can be very difficult for dependent users. There's little available evidence on the long-term mental effects of coke use.
Short term: E makes you feel relaxed, high, ‘loved-up’ and ready to dance all night. But bad experiences of paranoia or feeling ‘out of it’ can happen with high doses or to people who are already feeling anxious.
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 E gives them. Professor Nutt says:
"There’s no evidence so far of permanent depression after using ecstasy. Once people stop taking it their brains recover well."
Short term: heroin slows down the body functions and so stops both physical and emotional pain.
Long term: heroin can be physically 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.
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."
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. Some people find it hard to stop taking K."
Acid (LSD) and magic mushrooms
Short term: LSD and magic mushrooms are hallucinogenic, making people see, hear and experience the world in a different, ‘trippy’ way. But users may also become panicky and suffer from paranoia. Acid can last 12 hours or more which, if it’s a bad trip, can be very frightening. "Hospitals see significant numbers of teenagers coming in during the October ‘mushroom season’ with temporary psychotic problems," says Professor Nutt.
Long term: some LSD users experience flashbacks.
"Sometimes people get psychotic and paranoid, believing or seeing things that aren’t really there," says Barnes.
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.
Date published: Monday December 17 2007