lecture 11

• Psychoactive drugs


  Substances that achieve their effect by altering mood, thoughts, behaviour
• Psychoactive drugs


  • Typically used to treat symptoms of psychiatric illness
  • Effects achieved by: Facilitating actions of neurotransmitter receptor site, Inhibiting actions of receptor site, Regulating neurotransmitter availability in synaptic cleft
• Potency


  Absolute amount of a drug that is required to achieve a desired effect
• Efficacy


  Ability of a drug to produce a desired effect
• Dose


  Quantity or volume of drug that is administered
• Method of administration


  How is the drug consumed (e.g. oral, injection)
• Effective dose (ED)


  Dose needed to produce desired effect in majority of people with fewest possible side effects
• Classes of psychoactive drugs


  • CNS Depressants
  • Psychostimulants
  • Anti-depressants and mood stabilisers
  • Anti-psychotics
• CNS Depressants


  • Diminish environmental awareness & responsiveness
• Psychostimulants


  • Increase motor activity, reduce fatigue, relieve boredom, enhance task performance
• Anti-depressants / mood stabilisers


  • Elevate mood, increase physical activity, improve appetite and sleep patterns
• Anti-psychotics


  • To treat major psychoses like schizophrenia
• CNS Depressants


  Slow down brain activity, muscles relax, calming and soothing effect
• CNS Depressants


  • Benzodiazepines, other anxiolytics, barbiturates, some sleep medication, hypnotics, alcohol, THC
• Alcohol intoxication


  Slurred speech, Incoordination, Unsteady gait, Coma
• Alcohol withdrawal


  Benzodiazepines to improve agitation, lead to calmness, decrease seizures
• Alcohol hallucination


  12-48hrs after last drink, Often visual hallucations, Hearing voices, Tactile hallucinations
• Alcoholism therapy


  Disulfiram to break down ethanol into acetate (causes hangover symptoms)
• Psychostimulants


  • Nicotine, cocaine, amphetamines, methylphenidate (ritalin), ecstasy, caffeine, THC
• SSRIs and norepinephrine


  Correct slow functioning of CNS activity
• Caffeine


  Consumed by 90% of industrialised country populations
• Nicotine


  Considered second most used legal stimulant in world
• Abuse of prescription drugs has increased globally
• Prescription drug abuse and addiction vs physical dependence on drugs without addiction

  Intent: taken to treat diagnosed illness, Consequences: treatment's goal and effect is to improve quality of life, Control: patient and physician work together, Legality of substance use, Pattern of use is stable
• Anti-depressants: SSRIs and SNRIs


  Prevent reuptake of neurotransmitters in nerve terminals, Increase availability of neurotransmitters
• Serotonin


  Regulates mood in body, Too low: anxiety, suicidal thoughts, depression, obsessive-compulsive behaviour
• Norepinephrine


  Fight-or-flight, stress, sleep, attention, memory, mood, Too low: trouble concentrating, ADHD symptoms, signs of depression
• Psychosis


  Hallucinations or delusions; processing the world differently
• Antipsychotics


  Work by blocking dopamine effects, Typical/1st generation: used since 1950s, more body movement side effects, Atypical/2nd generation: 1990s onwards