Recreational Drugs

• Stimulants

  Stimulants are drugs that make you feel more alert.
• Stimulant - Caffeine

  When you drink a cup of coffee, the drug it contains – caffeine – takes effect within minutes. It then blocks chemical signals (adenosine) in your brain, stopping you from feeling sleepy. In moderate doses caffeine also improves mental ability – reaction times, memory and reasoning skills. It takes your body 3–5 hours to break down caffeine, which is why coffee at bedtime may stop you sleeping.
• Stimulant - Nicotine

  Nicotine works by mimicking the actions of a naturally occurring brain chemical, acetylcholine, by docking with its special receptor molecules. Some of these nicotine receptors in the brain activate part of the 'pleasure centre' and release dopamine, which could be responsible for nicotine's euphoric and addictive effects. Reaches the brain in about 7 seconds when absorbed through the lungs.
• Stimulant - Amphetamines

  are all based on the naturally occurring chemical, ephedrine. Scientists found that amphetamine affects the brain, increasing alertness and decreasing appetite. It increases the levels of two of the brain's chemicals, noradrenaline and dopamine.
• Stimulant - Cocaine

  Is a drug found in leaves of the coca plant. It exaggerates changes caused by at least two brain chemicals, noradrenaline and dopamine, increasing alertness and causing euphoria. 
• Stimulant - Pain killers

   When part of your body is injured, special nerve endings send pain messages back to your brain. Painkilling drugs interfere with these messages, either at the site of the injury, in the spinal cord or in the brain itself. Many painkillers are based on one of two naturally occurring drugs: aspirin and opiates.
• Stimulant - Opiates

  Originally derived from the opium poppy, have been used for thousands of years for both recreational and medicinal purposes. The most active substance in opium is morphine. Codeine, a less powerful drug, is also found in opium. Both these opiates relieve pain, relax muscles and cause drowsiness. All opiates mimic your body's own painkillers.
• Stimulant - Heroin

  When heroin enters the brain, it is converted into morphine, which binds to opioid receptors involved in pain perception and reward. These receptors are also in the brain stem, controlling essential functions like breathing and blood pressure. After injecting heroin, users experience a rush of euphoria, dry mouth, warm skin, heavy limbs, and mental cloudiness. This is followed by a state of alternating wakefulness and drowsiness known as "on the nod."
• Explain why heroin is so addictive

  • Heroin increases dopamine in the reward pathway  
  • Heroin stimulates the production of dopamine 
  • Leads to overstimulation of the dopamine neurons = euphoria 
  • Desensitisation to dopamine 
  • No longer get dopamine ‘hits’ from day to day stimuli 
  • Only thing that increases dopamine is the heroin 
  • Takes more of the drug each time to get the same euphoria 
• Sedatives

  Sedatives are drugs that calm you down. The oldest known sedative is probably alcohol, used for thousands of years. Sedatives are central nervous system (CNS) depressants, a category of drugs that slow normal brain function. There are various kinds of CNS depressants, most of which act on the brain by affecting the neurotransmitter gamma-aminobutyric acid (GABA). 
• Depressants - Barbiturates

  Are helpful in treating anxiety, tension, and sleep disorders.
• Depressants - Benzodiazepines, such as diazepam (Valium)

  can be prescribed to treat anxiety, acute stress reactions, and panic attacks. 
• How does addiction occur?

  Scientists think that all addictive drugs activate the brain's 'reward system', by increasing the release of the chemical dopamine from neurons in key areas of the brain. Dopamine release occurs after pleasurable experiences, for example after food or sex, but can also be induced by some drugs. Drugs that artificially increase dopamine release in this way may cause craving for more. It is possible that some people may have a genetic tendency to make them develop drug addictions extremely rapidly.