Drugs Profile: Heroin

Explanation of:

Mode of Action





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  • Created by: Issy H
  • Created on: 09-06-12 15:00

Mode of Action

  • Heroin enters the body via the blood and arrives at the synapse. Morphine which is produced by heroin is a pain killer and a depressent. 
  • It acts as an antagonist for GABA receptors, blocking the receptors, inhibiting GABA. 
  • GABA role is to slow down neural firing. Its partner Glutamate tries to adapt to maintain homeostasis
  • The Synapse floods with GABA as it is not being transmitted. There is then an over production of Glutamate
  • The process mimics endorphins which causes over production of the neurotransmitter dopamine, which stimulates the reward pathway creating a feeling of euphoria. 
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Short term effects:

  • pleasure feeling
  • pain reduction
  • rush: dry mouth, heavy limbs, flushing of the skin, sickness and 'itchy blood'.
  • relaxation, drowsiness, slowing of mental functions and heart rate. 
  • rush occurs 7 seconds after the injection. 

Long term effects: 

  • psychological and physical dependence
  • tolerance
  • withdrawal symptoms
  • cravings
  • HIV, Hepatitis, embolisms, clogging of blood vessels
  • breathing difficulties, poor immune system
  • risk of miscarriage
  • poor memory
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Physical Dependency:

  • Body needs heroin to function normally. 
  • Process of addiction. 
  • Brain produces less endorphins, addicts rely on heroin for pleasure and pain reduction. 
  • Withdrawal will occur.
  • Rapid tolerance causes quick dependency. 

Psychological Dependency:

  • Cravings are hard to resist.
  • Heroin becomes central to the users every day life. 
  • Important for the persons mental state. 
  • May help to get through social problems, lack of employment, dulling of the senses. 
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  • Heroin is taken over an increasing period of time, more of it will be needed to achieve the same initial high
  • A stage may be reached where no amount of drug achieves the high, and it is at this point that the addict would take heroin to avoid nasty withdrawal symptoms. 
  • The drug is needed for normal functioning, to maintain homeostasis
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  • Even if heroin is taken for 3 days, withdrawal can occur once it is stopped. 
  • The symptoms start 6 hours after the last drug, this is linked to tolerance and quantity of last dose. 
  • Includes: sweating, diarrhea, anxiety, depression, sensitivity, heaviness, cramps, insomnia, itchy blood. 
  • Because of withdrawl, a cycle of drug taking occurs. 
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