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.
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.
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.
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).