Lecture 29 - Behavioural and Clinical Aspects of Drug Dependence Flashcards Preview

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Flashcards in Lecture 29 - Behavioural and Clinical Aspects of Drug Dependence Deck (9)
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1

Parts of the brain particularly involved in drug dependence

Mesolimbic system.
Ventral temental area and nucleus accumbens projecting to the cortex

2

How does heroin affect the brain?

Binds to opioid receptors on GABA interneurons in the ventral tegmental area. This disinhibits VTA, leading to dopamine release

3

Heroin relapse rates

42% relapse within days of leaving detox
66% addicted 6 months after detox
48% still using after 6 years.
12% dead.
5% in prison

4

Aspects of physical dependence

Tolerance to drug, withdrawl

5

How can drug dependence lead to anhedonia?

Setpoint of dopamine-releasing reward system is set lower and lower. Requires greater stimulus to release dopamine

6

Evidence for conditioning aspect to drug addiction

Heroin addicts overly-responsive to opiate-related pictures, under-reactive to naturally-rewarding images

7

Brain areas affected by drug addiction

Orbitofrontal cortex (role in making choices)
Anterior cingulate cortex (role in long-term goals)

8

Outcomes of behavioural tests on drug addicts
1)
2)

1) Require more of the brain to be active to perform the same tasks as unaddicted people
2) Perform poorly on gambling tasks (always pick higher-stakes options, even though they know that they shouldn't)

9

Effects of nicotine on the brain

No effect on adults (apart from addiction), but can affect young female brains (greater incidence of depression)