Download Substance Abuse and Dependence

1. Substance Abuse and Dependence
(a) Definitions
i. Abuse
A. definitions vary; generally, abuse is defined as substance use which may result in
dependence, drug tolerance, and withdrawal symptoms (addiction).
B. Usually applies to illicit substances (i.e., drugs, or other controlled substances) but
can also refer to unsanctioned use of otherwise legal products such as paint, glue, or
gasoline
C. Abuse is not coextensive with actual addiction, but abuse often precipitates addiction
ii. Dependence
A. a physical, psychological, or behavioral state where the substance is necessary in
order to function normally
B. Occurs as a result of habituation; the “high” is reduced as the body acclimates to the
drug. In some cases, the body stops producing certain chemicals to counterbalance
the drug. When that occurs, weaning off the drug will produce withdrawal symptoms
until the body re-adjusts
C. Example: while cocaine, heroin, and alcohol create physical dependence, behavioral
dependence is much more common among marijuana users. In those cases,
“withdrawal” is experienced as a sense of anxiety or uncertainty about what to do
with yourself during times when you would have otherwise smoked, and increased
anxiety due to the need for other coping mechanisms besides marijuana.
iii. Tolerance
A. A physical state where increasing dosages are required to achieve the same effect as
the initial dose
B. “Chasing the Dragon” – as the body becomes more tolerant to the drug, the drug
loses its potency, creating a need to increase the dose
C. Overdoses occur for two reasons: either because of an unexpectedly pure or potent
dose, OR because of intentionally increasing the dosage to counteract the tolerance
effect
iv. Withdrawal and the Rebound Effect
A. Withdrawal symptoms are prima fascie evidence of dependence
B. usually they take the form of the opposite of the drug’s effect (rebound)
 example: alcohol withdrawal results in tremors, agitation, sweating, anxiety, and
CNS activation
 example: caffeine withdrawal results in crankiness, lack of concentration,
drowsiness, and migraines
C. Negative Reinforcement
 addiction becomes negatively reinforced when the illicit substance relieves the
uncomfortable symptoms of withdrawal
(b) Common Psychoactive Substances
i. Depressants – reduce CNS activity by acting as a GABA agonist, producing relaxation,
sedation, euphoria, amnesia, and in toxic doses, coma and respiratory arrest
A. HIGH potential for dependence and tolerance due to anxiety and physical discomfort
of withdrawal symptoms
 Alcohol

alcohol withdrawal can cause “delirium tremens,” an extremely dangerous
symptom which has a relatively high fatality rate
 Benzodiazepenes
 anti-anxiety medications (Xanax, Ativan) and the date-rape drug
(rohypnol/flunitrazopam)
 Barbituates
 Tranquilizers; generally not used for anxiety due to possibility of overdose
 Inhalants
 paint, gasoline, glue, rubber cement, etc.
 greater possibility of brain damage due to direct aspiration of chemicals into
the olfactory neurons
B. Anti-Histamines
 produce sedative effects by blocking the action of histamines, rather than GABA
receptors
 includes diphenhydramine (benadryl), which is sometimes prescribed off-label
for anxiety and insomnia (DO NOT DO THIS, YOU COULD DIE)
ii. Opiates
A. produce euphoria and pain relief (analgesia) by acting on opiate receptors in the
nucleus accumbens and sensory nerves
B. HIGH probability of dependence and addiction due to (a) positive reinforcement of
euphoria and (b) negative reinforcement of pain relief
C. withdrawal symptoms include severe, intractable pain which is usually not harmful
but which lasts for the duration of the withdrawal period due to temporary reduction
in endorphin production. This reduction MAY be permanent
D. substances include opium and its derivatives (morphine, heroin, oxycodone,
hydrocodone)
E. Overdose causes CNS arrest, coma, and death
iii. Stimulants
A. produce feelings of alertness, energy, resistance to fatigue, and positive mood
 by far the most commonly abused substances
 legal stimulants have mild withdrawal symptoms and low use cost, reducing
incentive to stop using
 Action varies by substance
B. Caffeine
 blocks adenosine receptors, which normally signal fatigue
 increases dilation of blood vessels in the body
 decreases dilation of cranial blood vessels, reducing headaches
 found in OTC migraine preparations, usually with acetaminophen, and in
prescription migraine medication such as Fioricet (with acetaminophen and
bulbital, a barbituate). Withdrawal CREATES migraines
C. Methylphenidate (Ritalin) and Amphetamine/Dextroamphetamine
(Adderall/Dexadrine)
 used to treat attention deficit disorder
 if abused, creates dependency and contributes to behavioral problems
 dopamine and norepinephrine agonists
D. Ephedrine and Psuedoephedrine

stimulate cranial nerves to reduce inflammatory responses (used as
decongestants), and used in the creation of methamphetamine
E. Nicotine
 acetylcholine agonist
 highly addictive
F. Cocaine
 Dopamine and Norepinephrine RI and increases DO and NE production
G. Amphetamines (and derivatives)
 includes methamphetamine, crystal meth, MDMA (Ecstasy)
H. Withdrawal symptoms include sluggishness, depression
I. Can cause “stimulant induced psychosis” due to increase in dopamine
iv. Psychedelics
A. increase dopamine and serotonin, thereby increasing euphoria and sensory
awareness
B. Generally not physically addictive due to varying experiences (i.e., the possibility of
a “bad trip”)
C. LSD
 increases dopamine and serotonin, producing perceptual hallucinations
 can also cause paranoia and terror (the bad trip)
D. THC
 low-dose hallucinogen which produces vague feelings of wellbeing as well as
heightened perceptual experiences
E. Psylocibin (Mushrooms)
F. Mescaline
G. Bufotenin
 with DMT, the hallucinogenic compound found in cane toad secretions (Bufo
means “toad”)
H. Ayahuasca
 brewed from plants containing dimethyltryptamine (DMT) combined with a
plant which yields an MAOI (which potentates the effect)
v. Dissociatives
A. produce out-of-body experiences, blackouts, anaesthesia (insensitivity to pain)
B. Ketamine
 better tolerated as an anaesthetic than PCP
C. Phencyclidine (PCP)
 initially used as an anaesthetic, but not tolerated well
 produces dissociative states and insensitivity to pain, causing individuals to be
extremely violent and unpredictable since they are not stopped by normal pain
stimuli