Addiction and dependance

Question 1

Addiction

Answer 1

Psychological, craving another hit.

Non- disordered drug use, habitual pattern or rhythm.

Question 2

Dependence

Answer 2

Physical, require the drugs to reach a normal state, physical withdrawal symptoms if drug is removed.

Question 3

Tolerance

Answer 3

Major part of dependence-addiction cycle, higher dose required for same hit

Question 4

Tachyphalaxis

Answer 4

Repeated dose of drug leads to lessened response, i.e. Tolerance.

Question 5

Sensitivity

Answer 5

Less common in drugs of abuse, repeated dose leads to increased response.

Question 6

I.V drugs of abuse

Answer 6

Instant hit, better high for lower concentration but doesn’t last long in blood

Question 7

Smoking drugs of abuse

Answer 7

Not as high plasma concentration, safer, more expensive, require higher concentrations for a big hit.

Question 8

Nasal / oral

Answer 8

Does not reach as high a plasma concentration but is convenient. More time to get hit, esp oral.

Question 9

Positive conditioning

Answer 9

Social situation, purchase and prep of drug can be exhilarating, adds to experience. Once drug is administered reward pathwya is activated. Makes you more likely to do it again. Antagonist response modifiers of the reward system could stop this.

Question 10

Ritualistic behaviour

Answer 10

Leads to excitement building, but if you take this away and repkace it with other things to do, less likely to take drug. I.e. Doing it out of boredom

Question 11

Epigenetics

Answer 11

Changes in the function (not sttucture) of DNA. PKa phosphorylation upregulates or downregulates genes.
Chronic drug use leads to unwinding of chromatin, allowing bits of DNA that were previously silent to bevome afyive. Never really revovers. When taking drugs body adapts to this and tries to function as normally as possible, withdrawl is when problems arise.

Question 12

Alcohol dependance

Answer 12

Heritable component (50-60%) often accompanied by anxiety and depression. Acts on dopamine reward pathway, releases endogenous opiods.
Withdrawal can be 6hrs to 10days.
Acetaldehyde is what causes worst effects of hangover. Using disulfiram you can inhibit aldehyde dehydrogenase, increasing levels of acetaldehyde leading to instant hangover which would help stop reward response.

Question 13

Nicotine

Answer 13

Rapid tolerance, rapid recovery, therefore many cravings.
Agonist at autonomic gaglia, skeletal musvle and CNS(VTA).
Dopamine antagonist such as nicorette greatly decreases self administration.

Question 14

Cocaine

Answer 14

Sympathomimetic and anaesthetic.
Withdrawal treated with dopamine agonists, uptake inhibitors and beta-blockers.
Potential for a vaccine that binds to cocaine decreasing its lipophilicity, can no longer cross BBB, no high, waste of money.