CH 9.3 (psychopharm)

Oral or transdermal

Route of administration: relatively slow absorption; slow drug availability to the brain

IV or inhalation

Route of administration: rapid drug entry into the brain and a fast onset of drug action; but shorter duration of action

• produce the strongest euphoric effects as a result of rapid drug delivery to the brain

Route with fast drug action

Have the greatest addiction potential; produce strongest euphoric effects and shortest latency

Short latency

Between response and reinforcer lead to:

• stronger and faster drug conditioning

• Addiction is more likely

Positive reinforcers

Consuming the drug strengthens whatever preceding behavior was performed by the organism

• eg. parking lot always smoked in

Drug reward

The positive subjective experience associated with the drug, euphoria or the high

Self administration tests

Drug reinforcement is studied using these tests

• strong reinforcers in these tests have high addiction potential for humans (cocaine, heroin, and meth)

Fixed ration (FR) schedule

The typical dose response function is an inverted U shape curve

At higher doses

At what doses does the number of reinforcers decline?

• due to satiation, aversive reactions, or behaviorally disruptive side effects

Progressive ration procedure

Animals are trained continuous reinforcement (CR) schedule then switched to a low FR schedule, increased until he animal stops responding (breakpoint)

Breakpoint

• animal stops responding, tells us how addictive drugs is

• Breakpoints can vary with dose

Reinstatement of drug seeking behavior

Relapse can be modeled by stopping drug delivery, then exposing animal to cue a cue previously paired with drug delivery

Stimuli effective in reinstatement

• experimenter delivers a small dose of the drug (drug priming)

• Subjecting the animal to stress

• Exposing animal to environmental cues that were previously paired with drug delivery

Slide 52

Negative consequences

• occur later of time, after a long period of use

• Family breakups, job loss, health effects etc

Individual factors that contribute to addiction development

Personality traits, mental health status, childhood experiences, lifestyle, present life stressors

Place conditioning

Animals associates one compartment with rewarding effect of a drug. One compartment paired with drug, then how long animal spend in each compartment is measured in drug free state

• IV: one compartment paired with drug w/o drug

• DV: time spent in each compartment

Electrical self stimulation

Electro is inserted in the brain’s reward circuits on performing an operant response. The threshold is reduced for self stimulating reward centers when animals have been treated acutely with drug of abuse.

Drugs are reinforcing

When under the animals control (self admin)

Drugs MAY be aversive

When administered by the experimenter

Physical dependence

Withdrawal May play a key role in establishing and maintaining drug addiction

• i want to do drugs to stop withdrawal symptoms

Withdrawal symptoms

Also called abstinence syndrome: motivates the user to take the drug again (negative reinforcement)

Agonist replacement therapy

Experimental results from heroin studies support the use of methadone or buprenorphine in the treatment of opioid dependence

• help with withdrawal

Slide 57

Development of addiction

Drug taking behavior progresses from an impulsive stage to a compulsive stage

• process due to gradual recruitment of antireward system in the brain (neuroadapted stage)

Impulse stage

An episode of binge drinking results in a pleasant state of intoxication.

• Because of the repeated pairing of intoxication with environmental stimuli, a conditioning process causes those stimuli to trigger a renewed craving for the alcohol reward.

• leading to more binging and intoxication

Compulsive stage

Individuals undergo periods of prolonged intoxication that bring relief from their depressed baseline mood state.

• they are now alcohol dependent, abstinence leads to withdrawal symptoms that include even greater negative effect

• Craving in this stage is related to relief from the state of withdrawal

Impulsive stage

What stage is this?

Compulsive stage

What stage is this?

Episodes of withdrawal

The responses can become classically conditioned to the stimuli associated with the environment in where it occurs

• symptoms, such as craving, can be triggered by exposure to the conditioned stimuli

Discriminative stimulus

Psychoactive drugs produce these effects in animals, thought to corrrespond to subjective effects produced by these compounds in human users.

• willing to work harder to administer substances

• Experienced users come to expect the subjective effects which contributes to the persistence of drug use

Genetic factors

Contribute to the risk for addiction, been assessed using family, adoption, and twin studies

Heritability

Of substance use disorders is in the range of 40% to 60%

• some substances like cocaine show higher

• Psychedelics show lower

Environmental influences

Remaining variability that contributes to risk for addiction

Adolescence increased risk

Of drug addiction is associated with younger age, less education, nonwhite racial background, lack of employment, and conduct problems in childhood

Psychosocial variables

Contribute to increased addiction risk

• adolescents

• Stress

• Mental health comorbidity

Stress

Frequent and severity of stressful life events and an individuals ability to cope with such events

Comorbidity

Diagnosis of anxiety, mood, or personality disorders in addition to substance abuse disorder

Self medication hypothesis

Individuals suffering from elevated anxiety should prefer sedative anxiolytic drugs; depressed individuals should seek out stimulants drugs

Shared etiology

Certain factors (genetic or environmental) contribute to elevated risk of both addiction and other psychiatric disorders

Familial and sociocultural influences

Childhood maltreatment, violence in the family, inadequate parental monitoring

Social facilitation

Promote this, remove user from normal social roles and responsibilities, promote solidarity within a particular ethnic group or lead to association with a specific drug to subculture

Protective factors

• Absence of risk factors

• Factors protecting against initiation; family cohesion, parental warmth/monitoring

• For people recovering; a support network, maintaining a stable lifestyle, sources of reinforcement

Men substance use misuse

Often begin in a social context

Women substance use misuse

• begin in response to a negative life events and/or onset of depression or anxiety

• Rapidly escalate substance use (telescoping)

• More sensitive to drug related cues

• Experience more severe drug craving

Sex differences in substance use

Linked to female reproductive hormones or to differences in stress responding

Natural recovery

Transitioning from substance misuse or addiction to non-problematic use or nonuse without assistance

• facilitated by transitional life events or by negative consequences of drug use

Maintaining abstinence

Helped by avoiding drug associated cues, non drug sources of reinforcement, new social support networks, financial stabilit, and achieving a general structure in life

Bio psychosocial model of addiction

Includes the full range of pharmacological, biological, and psychological/sociocultural factors that influence addiction risk

• promote the likelihood of substance misuse and addiction

Increases

Positive reinforcing effects of drug (Behavioral and neural mechanisms) INCREASES OR DECREASES compulsive drug seeking and drug use

Increases

Negative reinforcing effects of drug due to relief of withdrawal INCREASES OR DECREASES compulsive drug seeking and drug use

Increases

Discriminative subjective effects of drugs INCREASES OR DECREASES compulsive drug seeking and drug use

Increases

Stimuli conditioned to drug effects INCREASES OR DECREASES compulsive drug seeking and drug use

Decreases

Averse effects of drugs INCREASES OR DECREASES compulsive drug seeking and drug use?

Increases

Risk Factors (psychological, familial, sociocultural, and genetic) INCREASES OR DECREASES compulsive drug seeking and drug use

Decreases

Protective factors INCREASES OR DECREASES compulsive drug seeking and drug use