Drug therapies for addiction

• Opioid Receptors Antagonists

  Blocks opioid receptors, reduces craving, used in maintenance treatment
• Drug therapies

  There are three types of drug therapies that can be used when managing addiction:

  Aversives - Aversives work by producing unpleasant consequences (i.e. vomiting) to reduce use of the addictive substance.

  Agonists - Agonists are effectively drug substitutes. They bind to neuron receptors and activate them, thus providing a similar effect as the addictive substance.

  Antagonists - Antagonists treat addiction by binding to receptor sites and blocking them so that the dependent substance cannot have it’s usual effects
• Drug therapies

  There are three types of drug therapies that can be used when managing addiction:

  • Aversives - Disulfiram is a drug used to treat alcoholism by creating hypersensitivity to alcohol. It causes almost instantaneous and severe hangover effects (especially nausea)
  • Agonists - Methadone is an agonist used to treat heroin addiction. It has the same effects as heroin but is cleaner (in that it is delivered medically) and has fewer harmful side effects.
  • Antagonists - Naltrexone is an opiate antagonist that inhibits the feeling of euphoria that opioids give.
• Drug therapy for nicotine addiction

  You know this one…

  Nicotine replacement therapy (NRT) refers to the use of gum, inhalers, patches, vapes etc. to deliver the psychoactive substance in tobacco smoke but in a less harmful fashion. 

  Logic: Nicotine is the major addictive factor in smoking but in isolation not the most damaging to health, so ‘clean’ delivery with gradual reduction is dosage can be an effective method in reducing smoking behaviour

  But how does it work? 

  Task: 1 minute - recap the neurochemical explanation for me again
• Drug therapy for nicotine addiction - self assess

  NRT provides users with a clean controlled dose of nicotine which operates identically to the nicotine found in cigarettes

  1. Nicotine binds to nicotinic acetylcholine receptors in the mesolimbic pathway of the brain
  2. This stimulates the release of dopamine in the nucleus accumbens 
  3. The NA releases dopamine directly into the frontal cortex and produces the pleasurable effects associated with nicotine
• Drug therapy for nicotine addiction

  Using NRT means that the amount of nicotine can be reduced over time e.g. smaller patches, ‘weaning’ off of gum. 

  This allows the withdrawal syndrome to be managed over a period of months, thus reducing the aversiveness of the withdrawal symptoms.
• Drug therapy for gambling addiction

  There are currently no officially approved drugs for use in the treatment of gambling addiction.

  However there is ongoing research into several options with the most promising being opioid antagonists such as naltrexone. 

  This has arisen due to newly acknowledged similarities between gambling and substance addiction in the DSM-5
• Opioid antagonists have a round about effect on gambling behaviour. 

  They reduce the release of dopamine in the NA by enhancing the release of another neurotransmitter GABA

  GABA is released in other parts of the mesolimbic pathway and works by dampening down the cravings associated with gambling addiction
• Drug therapy for gambling addiction

  HOWEVER

  Naltrexone causes rather unpleasant side effects so efficacy is negatively impacted here. 

  But opioid antagonist treatments are still considered a highly promising potential treatment for gambling addiction
• What is one limitation of drug therapies for addiction?

  They are reductionist in nature
• What do drug treatments for addiction primarily focus on?

  Biological mechanisms like dopamine and GABA
• How do drug therapies neglect the maintenance of addiction?

  They ignore environmental influences
• Why might smokers using NRT still relapse?

  Due to social pressures from friends and family
• What is a consequence of drug therapies not accounting for environmental factors?

  They cannot be considered fully effective
• What are the key criticisms of drug therapies for addiction?

  • Reductionist approach
  • Focus on biological mechanisms
  • Neglect of environmental influences
  • Ineffectiveness in certain social contexts