Substance Addiction

Question 1

Course of addiction

Answer 1

Experimental/recreational use - increasing long regular use - spiralling and dependency

Question 2

Dependence syndrome

Answer 2

Desire or compulsion
Difficulty in controlling 
Withdrawal
Tolerance 
Neglect of other interests 
Persistence of drug use

Question 3

Addiction vs dependence

Answer 3

Addiction - compulsive drug use despite consequences - inability to stop
Dependence - physical adaptation to substance such as tolerance or withdrawal

Question 4

Addiction cycle

Answer 4

Normal circumstance - excitatory system (glutamate - NMDA receptor) and inhibitory system (GABA-A receptor) in balance

Acutely alcohol - excitatory system blocked and inhibitory boosted

Chronic - upregulation of excitatory system and reduced function in inhibitory - in absence of alcohol GABA and glutamate are no longer in balance

Treat with benzodiazepines to boost GABA function

Question 5

Medication for remaining abstinence

Answer 5

Acamprosate - reduces NMDA function

Question 6

Rewards system

Answer 6

Dopamine in ventral striatum
Drug abuse also increase level of dopamine
Addiction is reward deficit state

Question 7

Interaction between substance of abuse and dopamine

Answer 7

Cocaine, amphetamine block reuptake

Amphetamine enhance release of DA, other drugs increase dopamine neuron firing in VTA

Question 8

Brain response to anticipation of winning money

Answer 8

Blunted activation of reward system in abstinent addicts

Higher activity in reward pathway associated with abstinence at follow up

Question 9

Aversive reaction following withdrawal

Answer 9

In amygdala

Heightened reaction to negative imaging

Question 10

Striatum change

Answer 10

Change from ventral (emotional) to dorsal striatum (habit)