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Substance Abuse Criteria (DSM-IV)
- Recurrent substance use resulting in a failure to fulfill major role obligations
- Recurrent substance use in situations in which it is physically hazardous
- Recurrent substance-related legal problems
- Continued substance use despite having persistent or recurrent social or interpersonal problems.
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Substance Abuse and Dependence
- Corresponds roughly to the notion of addiction
- Must be maladaptive - harm is occurring to the user
- Drug seeking and drug use become impulsive (lose control)
- Individuals escalate their use
- Individuals remain "addicted" for long periods of time and drug-free periods (remissions) are often followed by relapses in which drug use occurs in vicious cycle
- Relapse is driven by a strong urge or craving for the drug that can be elicited by cues, the drug, or stress
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Why do people become addicted/dependent on drugs?
- Drug dependence
- Assume consumption is under voluntary control (individuals can stop if they "want" to)
- Physical dependence
- Attempts to abstinence lead to highly unpleasant withdrawal symptoms
- Repeated abstinence attempts followed by relapses
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Drug with no withdrawal symptoms
Cocaine
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Incentive motivational effects
- Distinguishes between drug liking (that is, the high) and drug wanting (that is, craving)
- Marked increase in wanting the drug even though there is no change or even a decrease in drug liking (as a result of tolerance for example)
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Biopsychology View of "Addiction"
- Result of long-term neuroadaptions in the brain that are caused by chronic drug use
- Damage to the Go System (subcortical) vs. No Go (prefrontal cortex) - Hypofrontality
- Vulnerability to addiction is heightened during early exposure to drug use
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Mesolimbic Dopamine System
- The "rewarding" effects of drugs are attributed to dopamine within the mesolimbic system (VTA to Nucleus accumbens)
- Referred to as "reward pathway"
- Activated by:
- Natural rewards (e.g. sex)
- Drugs of abuse (e.g. cocaine, morphine, nicotine, alcohol)
- Conditioned stimuli (stimuli associated with the drug)
- Stress
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Alcohol
A powerful depressant that dtrongy influences consciousness and the ability to respond effectively to the environment
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Blood alcohol content (BAC)
Objective measure for examining alcohol's effects
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Effects of Alcohol on the CNS
- Enhances GABA (main inhibitory neurotransmitter) receptors by enhancing GABA function
- Decreased glutamatergic transmission by inhibiting the NMDA receptor and decreasing levels of glutamate (main excitatory neurotransmitter)
- Elevates levels of dopamine by enhancing activity of the mesolimbic pathway
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Withdrawal from Alcohol
Opposite effects on CNS
- Decreased GABA function
- Increased Glutamate function
- Decreased dopamine function
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5-6 hours after drinking
- Tremors
- Headache
- Nausea
- Sweating
- Vomiting
- Abdominal Cramps
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15-30 hours after drinking
Convulsive activity
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24-48 hours after drinking
- Delirium tremens
- Disturbing hallucinations
- Bizarre delusions
- Confusions
- Tachycardia (rapid heart beat)
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Korsakoff's syndrome
- memory loss
- sensory and motor dysfunction
- eventually dementia
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Fetal alcohol syndrome
Result of pregnant women abusing alcohol, with permanent damage to the fetus
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Alarm Reaction to Stress
- The hypothalamus activates the sympathetic nervous system.
- The adrenal gland is then stimulated and releases epinephrine and norepinephrine hormones.
- The hypothalamus also stimulates the anterior pituitary to release hormone that drive the outer part of the adrenal gland, the adrenal cortex, to release hormones such as cortisol.
- All of these hormones prepare the body for immediate action.
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Self-administration
Examine the reinforcing effects of drugs
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Conditioned place
Examine drug reward
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Sensitization
Examine the effects that became more enhanced with repeated exposure
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