Psychostimulants (& ADHD/catecholamines)

Question 1

Psychostimulants

Answer 1

These mimic the sympathetic nervous system, elevate mood, and increase energy and stamina. They are both commonly used for medicinal purposes as well as commonly used as stimulants.

“Psychostimulant” and “stimulant” are different words for the same thing. Many psychostimulants are classified as sympathomimetics.

Question 2

Six general categories of psychostimulants

Answer 2

Ephedrines, pseudoephedrines, amphetamines, methamphetamines, methylphenidates, cathinones

Question 3

Ephedra

Answer 3

Plant with ephedrine and pseudophedrine. Used as a decongestant (Sudafed). Also used for weight loss, increased energy, etcetera. Is a relatively mild stimulant in comparison to many others.

Banned in the USA in 2004, but not in Canada. Can be found in supplement stores.

Question 4

Amphetamines

Answer 4

Comes in forms like: Adderall, Vyvanse (inactive prodrug converted in body), Benzedrine (amphetamine inhaler). All have similar effects but have different half lifes, different ways they metabolize, etcetera.

Used extensively in WWII to help soldiers stay awake and alert.
Useful in congestion, narcolepsy, weight loss, ADHD, chronic pain, “performance enhancement.”

Narcolepsy is a disorder of hypersomnolence/sleepiness.

Aside: Amphetamines contain optical isomers dextroamphetamine (D) and/or levoamphetamine (L). A mixture of the both is called a racemic mixture.

Question 5

Methamphetamine

Answer 5

Similar to amphetamines. Also known as Desoxyn (uncommonly, Desoxyn can be obtained by prescription) or on the streets, “crystal meth.”

Highly addictive, and detrimental to habitual users. Stimulant psychosis frequent with high doses.

Stimulant psychosis is stimulant-induced psychosis. Psychosis involves hallucinations, delusions and/or paranoia.

Question 6

Methylphenidate

Answer 6

AKA Ritalin, Concerta, first line treatment for children with ADHD due to the fact it is shorter-lasting and weaker than amphetamines. This has its cons as well as children may have to take multiple doses per day.

Also used in adults with ADHD.

Question 7

Cathinones

Answer 7

The plant Catha edulis, or khat, is a benign cathinone stimulant. If khat is synthesized into a drug like ‘bath salts,’ it becomes more powerful and less benign.

‘Bath salts’ are taken by ingestion/inhalation.

They’re called bath salts, because that’s what the synthetic product is marketed as to find a loophole in laws.

Question 8

Cocaine

Answer 8

Derived from the coca plant, which has been used historically.

Can also be used as an anaesthetic, analgesic (pain reliever), and constricts blood vessels. Blocks action potentials (voltage gated sodium channels are blocked) thus brain doesn’t send certain signals to the body.

Cocaine salt is insufflated (snorted) and injected, the free. base (crack) inhaled. The free base is called crack because it makes a crackling noise when smoked through a crack pipe.

Can also be used legally in dental work.

Question 9

Sigmund Freud wrote many of his concepts under the influence of ____.

Answer 9

Cocaine. Freud even wrote a book called Über Coca as a ‘love letter’ to cocaine. Freud also did not believe cocaine was addictive.

Question 10

Are synthetic drugs typically more or less potent/concentrated than the plants they come from?

Answer 10

Synthetic drugs are typically more potent than than the plants they come from.

Question 11

Intravenous, insufflation, inhalation

Least to most efficient way to get drug effects

Answer 11

Inhalation -> Intravenous -> Insufflation (Peak effect MUCH faster in insufflation than other two methods.

Question 12

Polydrug Use

Answer 12

Taking two different drugs that metabolize in the body to form more effective active metabolites.
Eg. Cocaine + alcohol (aka ethanol) = cocaethylene, which has a longer half-life than cocaine

Question 13

Cocaine action mechanisms

Answer 13

Blocks dopamine transporters (DAT) from reuptaking dopmine, thus more dopamine proliferates within the brain.

Question 14

Half-life of amphetamines

Answer 14

10-11 hours

Question 15

Half-life of methylphenidate

Answer 15

2 hours

Question 16

Half-life of cathinones

Answer 16

1.5 hours

Question 17

Half-life of cocaine

Answer 17

1 hour

Question 18

Low doses of psychostimulants increase ____ behaviour while higher doses increase ____ behaviour.

Answer 18

Low doses: Increase purposeful behaviour
High doses: Increase purposeless behaviour

Question 19

Stereotypy/Punding

Answer 19

(Purposeless) Repetitive motor movement: Scratching, skin picking, etc.

This increases with higher doses of psychostimulants.

Question 20

Cocaine biomechanisms

Answer 20

Cocaine displaces vesicular dopamine/pushes dopamine out into synaptic cleft, as well as blocks dopamine’s reuptake.

Question 21

DAT

Answer 21

Dopamine transporter

Affected by psychostimulants (increase in dopamine).

Question 22

NET

Answer 22

Norepinephrine transporter

Usually affected by psychostimulants (increase in norepinephrine).

Question 23

SERT

Answer 23

Serotonin transporter

Usually affected by psychostimulants (increase in serotonin).

Question 24

Physiological effects of psychostimulants

Name as many as you remember

Answer 24

Increased heart rate, blood vessel constriction, airway relaxation, digestion inhibition, pupil dialation, increased body temperature, dry mouth

Question 25

Subjective effects of psychostimulants

Name as many as you remember

Answer 25

Increased energy, euphoria, increased alertness, improved sense of well-being, anxiety, agitation

Question 26

Animal Experiments

Vehicle pretreatment, training drug pretreatment, test drug pretreatment

Answer 26

1. Vehicle pretreatment: Inject a rat with placebo/saline, teach it to press a lever for food.
2. Training pretreatment: Inject the rat with a comparative drug to the one you want to test, see its behaviour of lever pressing.
3. Test pretreatment: Inject the rat with the new drug, see its behaviour of lever pressing.

Question 27

Adverse effects of psychostimulant use

Name as many as you remember

Answer 27

• Cardiovascular dysfunction (especially in high doses of cocaine, a Na+ channel blocker)
• Pulmonary dysfunction
• “Meth mouth”/tooth decay from reduced salivation (and secondarily, poorer dental habits)
• Psychostimulant-induced psychosis
• Formication (hallucination of bugs underneath one’s skin)
• Tactile hallucinations common in high doses of meth
• Neuron damage (possibly)
• Developmental disorders (when individuals use stimulants while pregnant)

Question 28

Sensitization vs tolerance of potent psychostimulants

When do they occur, and what specific effects do each of them have

Answer 28

Tolerance: Occurs more often with continuous drug use, more pronounced for the reinforcing effects of the drug (eg. euphoria).
Sensitization: More stereotypy (even with intermittent use), cravings, and incentive sensitization (addictive properties) with repeated use

Question 29

Are men or women more likely to have a psychostimulant addiction?

Answer 29

Women

Possibly due to societal reasons? Eg. Stimulants for weight loss

Question 30

What are two primary predictors of addiciton?

In the sense of how the drug itself is used rather than the person’s environment

Answer 30

Route of administration (eg. oral less addictive than sufflation) and polydrug use

Question 31

Polymorphism gene

Answer 31

Decreases susceptibility to psychostimulant addiction.

This gene makes dopamine less likely to get converted into norepinephrine, thus more dopamine stays dopamine when someone takes a stimulant. This build-up reduces the positive feelings/effects from psychostimulants and increases aversive effects.

Question 32

Cue-induced reinstatement

Answer 32

Cues increase craving of drugs in withdrawal periods. Thus mental cues (environments, seeing the drug, etc.) can activate physical cravings.

Cocaine cravings increase over time of withdrawal, until about 6 months after quitting.

Question 33

What is likely to cause transition from recreational to chronic use

Answer 33

The more access an animal has to drugs, the more likely they are to administer the drug for themselves. They then begin to escalate their intake.
This may be why people get addicted after multi-day drug binges/benders.

Question 34

Two primary phases of recovery

Answer 34

Detoxification, relapse

Question 35

Disulfiram

Answer 35

Used for treatment of psychostimulant (and alcohol) addiction. Disulfiram prevents the conversion of dopamine to norepinephrine and causes averse effects when taking stimulants/reduces pleasurable effects.

Sometimes this will not work, as people will often go off disulfiram instead of going off the psychostimulant.

Question 36

Modafinil

Answer 36

Part of drug-replacement therapy. Modafinil is a psychostimulant with lesser effects than many addictive psychostimulants.

Sometimes will not work as Modafinil itself has abuse potential.

Question 37

Tricyclic antidepressants (for treating drug addiction)

Answer 37

Reduces the psychological effects of withdrawal. Treating the depression that comes with psychostimulant withdrawal can increase the likelihood of the person being able to come off the addictive drug.

Question 38

Anticonvulsant drugs

Answer 38

Theoretically will dampen excitability from psychostimulants. Not necessarily effective, but some evidence of efficacy.

Question 39

Psychostimulant vaccines

Answer 39

Vaccines meant to reduce usage of a psychostimulant (recently, used for cocaine addicts). Shows short term promise but effects seem to diminish in the long term.

Question 40

Attention deficit / hyperactivity disorder (ADHD)

Define ADHD and recall the theory of what ADHD is driven by.

Answer 40

Symptoms: Extreme inattention, hyperactivity (in some), impulsivity. Diagnosed in about 1/10th of individuals aged 4-17 (USA). First-line treatment is psychostimulants, as theoretically, ADHD is driven by low dopamine function.

Question 41

Catecholamines

Answer 41

Hormones/neurotransmitters made by the adrenal glands & released into the body. An umbrella term of sorts for epinephrine, norepeniphrine and dopamine.

Catecholamines are a sub-class of monoamines.

Question 42

Yerkes-Dodson Curve

Answer 42

Models the relationship between stress and task performance. Proposes one reaches their peak level of performance with an intermediate level of stress/arousal (intermediate depending on the person).

The curve is seen in pre-frontal cortex (PFC) monoamines. More catecholamines, more alertness. High amount of catecholamines = stress/shuts off the PFC.

Question 43

Psychostimulant use may have a ____ on brain development in ADHD

Answer 43

“normalizing effect”

Psychostimulants generally have been shown to have far more positive than negative effects on individuals with ADHD.

Question 44

Brain anatomy

High levels of catecholamines can suppress the ____

Answer 44

Prefrontal cortex

Question 45

Drug diversion

Answer 45

Transfer of prescription drugs to someone they’re not intended for (eg. someone on ADHD meds selling their medication to someone else)

Question 46

Nootropics

Answer 46

Another word for “smart drugs” or “cognitive enhancers.” The only nootropics that evidently work are psychostimulants (caffeine, nicotine, etc.). No evidential support for putative (supposed) nootropics (ginseng, gingko, omega-3s).