Substance Abuse, Dependence and Tolerance

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1. What is the differences between the classifications: substance abuse, dependence and tolerance? What type of behaviors are associated with each?

SUBSTANCE ABUSE

1. ABUSE: Persistent use of a pharmacologically active substance despite objective evidence of detrimental effects on the user.

2. DEPENDENCE: The pharmacological phenomenon of dependence and withdrawal.

a. TOLERANCE: Increased dosage required to achieve the same effect

i. Metabolic Tolerance: Increased production of metabolic enzymes ------> increased and more rapid metabolism and excretion of drug.
ii. Neuronal Tolerance: Down or up regulation of neuronal receptors involved in mediating the effect of the drug.

i.e., Alcohol Tolerance ------> overstimulation of GABA (hypnotic) receptors ------> down regulation of GABA receptors.

WITHDRAWAL: Observable rebound response when the drug is removed.

ADDICTION: Drug seeking behavior. Going to all ends (enduring discomfort, breaking the law) to assure a ready supply of the drug. It quickly follows dependence, although context of drug use does make a difference (medicinal -vs- recreational).

Factors determining addiction:

a. RISK-TAKING behavior (Cluster B personalities) are at increased risk for trying the drug initially, which is a factor in addiction to illicit drugs -- but not to alcohol.

b.CONTEXT: Analgesic use of opiates is not associated with increased risk of drug-seeking behavior.

c.DRUG PROPERTIES: Highly euphoriant drugs with short-half lives (Heroin, Cocaine) induce the strongest addiction the quickest. They result in almost instantaneous development of tolerance and withdrawal.

d. Risks of Dependency: Alcoholics are at increased risk if they can tolerate the adverse effects of alcohol when young. ...