Textbook Notes (362,812)
Canada (158,056)
Psychology (9,546)
PSYC62H3 (273)
Chapter 6


9 Pages
Unlock Document

University of Toronto Scarborough
Suzanne Erb

Chapter 6 TORERANCE AND DEPENDENCE What is tolerance? - Drug tolerance occurs when there is decreased susceptibility (diminished response) to the effects of a given amount of drug as a result of previous exposure, typically caused by repeated exposure to the drug. - Increasingly larger doses of drug are required to induce the same behavioural effect. - Tolerance due to drug exposure id different from so-called genetic or dispositional tolerance, whereby an individual may not be effected by the drug as much as other individuals are because of genetic or dispositional factors. - Although tolerance generally requires several drug exposures before it is evidenced, there is a special case of tolerance in which a noticeable decrease in the organisms sensitivity to the drug occurs over very short period of timeon the order of few hours. = tachyhpylaxis or acute tolerance - In this form of tolerance, the same amount of drug administered on two separate occasions a couple of hours apart may induce greater effects with the first dose than with the second doses. - Tachyphylaxis is also evident when the behavioural or physiological effects of a given dose of drug dissipate at a faster rate than the rate at which the drug is eliminated from the brain. - Cross-tolerance refers to the phenomenon in which the development of tolerance to one type of drug results in decreased sensitivity to the effects of another type of drug. - Most psychoactive drugs we take in our culture are not especially harmful in and of themselves when taken in reasonable quantities with sufficient time between administrations. - Once tolerance to a drugs effects develops, larger and more frequent doses that do become toxic are often administered. - Second, tolerance to the effects ofdrugs does not develop uniformly; that is, some effects may show profound toerelance whereas others may show little or no tolerance. - This is a distint problem with alcohol and many sedative-hypnotic drugs, where the beneficial or recreastional effects of the drug may show considerable tolerance, but little tolerance developed to the lethal effects of these drugs. - In effect, with this type of tolerance, the therapeutic index for these drugs gets smaller and smaller. - With other drugs, tolerance to the desirable effects of a drug may occur while the person actually becomes more sensitive to the side effects of the drug. - Eg. The ability of amphetamine to induce euphoria decreases with regular use, but the ability for amphetamine to induce psychotic-like effects may actually increase with regular use of large doses. www.notesolution.com
More Less

Related notes for PSYC62H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.