PSY 241 Lecture 19

• 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.

• 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

• 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

Cocaine

• 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)

• 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

• 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

A powerful depressant that dtrongy influences consciousness and the ability to respond effectively to the environment

Objective measure for examining alcohol's effects

• 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

Opposite effects on CNS

• Decreased GABA function
• Increased Glutamate function
• Decreased dopamine function

• Tremors
• Headache
• Nausea
• Sweating
• Vomiting
• Abdominal Cramps

Convulsive activity

• Delirium tremens
• Disturbing hallucinations
• Bizarre delusions
• Confusions
• Tachycardia (rapid heart beat)

• memory loss
• sensory and motor dysfunction
• eventually dementia

Result of pregnant women abusing alcohol, with permanent damage to the fetus

liver damage

• 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.

Examine the reinforcing effects of drugs

Examine drug reward

Examine the effects that became more enhanced with repeated exposure