Psychopharmacology

Factors influencing drug effects:  

  • Biological factors: inherited differences in reactions to drugs- initial sensitivity, gender, weight, age  

  • Psychological factors: personality (sensation seeking); “addictive personality”; drug expectancies and beliefs 

 

Social and environmental factors: 

  • Setting: influences effects of alcohol, marijuana, hallucinogenic drugs; whether using alone or with others  

 

Tolerance:  

  • Dispositional tolerance: Increase in the rate of metabolizing a drug with regular use (how fast does your body metabolize it) 

  • Functional tolerance: decreased behavioral effects of a drug with regular use  

  • Acute tolerance: a type of functional tolerance occurring within a single drug dose (tolerance in a short period time, ex: cigarettes) 

  • Protracted tolerance: a type of functional tolerance occurring over 2 or more drug doses  

  • Behavioral tolerance: adjustment of behavior through experience in using a drug (learned tolerance, change in behavior)  

  • Cross-tolerance: tolerance to a drug never taken before resulting from protracted use of other drugs  

 

Explanations of tolerance: 

  • Cell adaptation theory or homeostasis hypothesis  

    • Plasticity of CNS 

    • Reduced synthesis of neurotransmitter 

    • Reduced number of receptor sites = down regulation  

  • Drug compensatory reactions and learning  

    • Biological homeostatic counterreactions 

    • Conditioned stimuli may elicit compensatory reactions  

  • Body tries to keep homeostasis, so it over compensates before you take the drug, so after taking it you are still in homeostasis  

 

Behavioral pharmacology: 

  • Reinforcement and punishment  

  • Operant principles and drug dependence  

  • Drug discrimination study  

  • Conflict paradigm  

 

Animal models and human drug use: 

  • Causal relationship established between drugs and functioning  

  • Ethical issues:  

    • Strict federal regulations guide treatment of animals  

    • Three Rs in research planning: 

      • Reduce the number of animals used to a minimum 

      • Replace use of animals with alternatives if possible  

      • Refine experimental methods to minimize potential pain or distress 

 

Human behavioral pharmacology: 

  • Responsible, voluntary, informed consent of human participants  

  • Placebo controls: control group, enables placebo control (to rule out placebo effects) 

    • Argument that its unethical to give ill people placebos  

    • But only placebo control groups establish that the chemical action of the drug being tested is responsible for the effects  

 

New drug development: Need clinical trials, and FDA approval   

  • Three ways new drugs are found: 

    • Rediscovery of traditional uses of naturally occurring products  

    • Accidental observation of an unexpected drug effect  

    • Synthesizing of known or novel compounds  

  • Three phases of clinical trials  

    • Phase 1: healthy human volunteers, to determine safety  

    • Phase 2: human diagnosed with target disease, to determine efficacy  

    • Phase 3: expands phase 2 with more patients, less controlled trials  

  • Commercial status: drug is given a chemical name, brand name, generic name  

    • Drug companies usually have sole rights to market a drug for 20 years after filing a patent  

    • Generic drugs come out after the 20 years  

    • Drug companies object to generics after all the time, and money spent making it  

    • Generic drugs are equivalent in effect to brand names, but cost 50% less 

    • Generic drugs lower the cost of health care