Drug Therapy

• ASSUMPTION APPLICATION - NEUROTRANSMITTERS

  changes in the brain's neurotransmitter system affects mood, emotion and behaviour > any alteration/imbalance in the levels of certain brain chemicals impacts 'normal' function (e.g. positive Schizophrenia symptoms)

  by altering the levels of certain chemicals with the use of psychotherapeutic drugs > treat symptoms of certain psychotic disorders - drugs target / block the function of different neurotransmitters in the brain
• ASSUMPTION APPLICATION - LOCALISATION OF BRAIN FUNCTION

  structure and function of different brain areas and the impact they have on our mood and behaviour (e.g. limbic system - regulates emotions, any disturbances affect our mood)

  certain drugs target neurons in certain brain areas to improve symptoms (e.g. mesolimbic pathway - D2 dopamine receptors have a role in positive Schizophrenia symptoms)

  > Antipsychotics target the action of D2 neurons to reduce symptoms
• ASSUMPTION APPLICATION - MEDICAL MODEL

  assume all behaviours have a biological basis

  bio approach assumes all behavioural and mental illnesses are caused by physiological factors

  assumption apply the view that mental illnesses should be treated in the same way as physical ones > through physical treatments

  people with psychological disorders would be treated through the direct manipulation of their biological bodily processes / biochemistry levels
• MAIN COMPONENTS - ANTIPSYCHOTIC DRUGS - intro

  people with psychosis lose touch with reality and have poor insight into their condition

  positive symptoms of Schizophrenia are thought to be caused by high levels of dopamine in parts of the brain > dopamine neurons fire too often > overstimulation and positive symptoms

  may have abnormally high numbers of dopamine receptors (D2) on receiving neurons > more dopamine binds + neurons fire
• MAIN COMPONENTS - FIRST GEN, TYPICAL ANTIPSYCHOTICS

  e.g. chlorpromazine

  dopamine antagonist - binds to postsynaptic receptors and blocks the function of chemicals

  targets over active dopamine neurons to reduce levels

  targets specific dopamine receptors > D2 receptors (binds and blocks) > found in nucleus accumbens, part of mesolimbic pathway

  reduces dopamine stimulating neurons > reduces symptoms caused by increased dopamine levels
• MAIN COMPONENTS - NEWER, 2ND GEN, ATYPICAL ANTIPSYCHOTICS

  e.g. clozapine

  also works by blocking dopamine action at D2 receptors

  however - some negative schizophrenia symptoms are linked to dopamine activity at D1 receptor sites ( frontal lobe ) - so new drugs take action there too

  more temporary effect in brain, only temporarily occupies receptors then rapidly disconnects to allow normal dopamine transmission to continue > explains why it's less likely to cause side effects
• MAIN COMPONENTS > DRUG THERAPY FOR ADDICTION - AGONIST DRUGS

  mimics effect of substance/neurotransmitter and binds to postsynaptic receptors and activates a response in the same way
• MAIN COMPONENTS > DRUG THERAPY FOR ADDICTION - AGONIST DRUGS

  E.G - METHADONE - heroin / opiod addiction

  binds to opioid receptors (brain) + activates them in a similar way to heroin

  increases dopamine activity as heroin replacement and causes enough stimulation to reduce heroin cravings and prevents addict going into withdrawal

  stored in liver/blood > released slower than heroin > less highs + crashes, smaller, safer and controlled

  occupies receptors for longer to discourage other opiod use + maintains opiod addiction in a safer way until they can achieve abstinence
• MAIN COMPONENTS > DRUG THERAPY FOR ADDICTION - ANTAGONIST

  blocks effect, binds to receptors and blocks

  treat opiod addiction, alcoholism and gambling

  E.G. NALTREXONE

  binds to opiod receptors (brain) and blocks addiction effect

  if used > no pleasure / increase in dopamine > addiction = less rewarding > less likely to engage

  reduces cravings as addiction no longer leads to pleasure