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.
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
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
Drug with no withdrawal symptoms
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)
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
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)
A powerful depressant that dtrongy influences consciousness and the ability to respond effectively to the environment
Blood alcohol content (BAC)
Objective measure for examining alcohol's effects
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
Withdrawal from Alcohol
Opposite effects on CNS
- Decreased GABA function
- Increased Glutamate function
- Decreased dopamine function
5-6 hours after drinking
- Abdominal Cramps
15-30 hours after drinking
24-48 hours after drinking
- Delirium tremens
- Disturbing hallucinations
- Bizarre delusions
- Tachycardia (rapid heart beat)
- memory loss
- sensory and motor dysfunction
- eventually dementia
Fetal alcohol syndrome
Result of pregnant women abusing alcohol, with permanent damage to the fetus
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.
Examine the reinforcing effects of drugs
Examine drug reward
Examine the effects that became more enhanced with repeated exposure