PSY4080 D 6.0 Addictive Behaviours 1. PSY4080 D 6.0 Addictive Behaviours 2 Addictions A physical dependency to a substance results in withdrawal symptoms

PSY4080 D 6.0PSY4080 D 6.0 Addictive BehavioursAddictive Behaviours 11

Addictive BehavioursAddictive Behaviours


AddictionsAddictions

A physical A physical dependencydependency to a substance to a substance results in withdrawal symptoms in its results in withdrawal symptoms in its absence.absence.

Dependency: Dependency: persistent intake of drug even persistent intake of drug even if there is known harmif there is known harm

ToleranceTolerance: increasing doses are needed : increasing doses are needed over time to produce same effectover time to produce same effect• decrease in the sensitivity/number of receptors for decrease in the sensitivity/number of receptors for

that drug that drug • decreased sensitivity of intracellular mechanism decreased sensitivity of intracellular mechanism

responsible for drug’s effectsresponsible for drug’s effects

WithdrawalWithdrawal: symptoms opposite to those : symptoms opposite to those produced by the drug when it is no longer produced by the drug when it is no longer takentaken


PrevalencePrevalence

Varies by substance Varies by substance (Report on Smoking in Canada (Report on Smoking in Canada

2001, Canadian Addiction Survey 2004)2001, Canadian Addiction Survey 2004):: Nicotine: 21.7%Nicotine: 21.7% Heavy alcohol consumption (5+ drinks more Heavy alcohol consumption (5+ drinks more than once a week): 6.2%than once a week): 6.2%

Cannabis: 14.5%Cannabis: 14.5% Cocaine: 1.9%Cocaine: 1.9% Other “heavier” drugs: <1%Other “heavier” drugs: <1% Food, shopping, pornography, etc: ???Food, shopping, pornography, etc: ???


Case StudyCase Study

Leslie Ann, a 16-year-old female addicted to crack cocaine and alcohol, was the mother of a 5-month-old infant son. According to hospital reports, within an hour of the child’s birth Leslie Ann had left the obstetrics ward and did not return. It was later learned that she had been looking for a “hit.” Following this episode, the infant’s prenatal exposure to crack was documented and Child Protection Services subsequently placed the infant in foster care. At presentation, Leslie Ann was attending a drug rehabilitation program as a prerequisite for regaining custody of the child.



Leslie Ann had started using cocaine as a teenager. She soon became addicted, left school and engaged in petty criminal activities, as well as prostitution, in an effort to raise money for her habit. She attempted unsuccessfully to stop using drugs and alcohol when she learned of her pregnancy. During the pregnancy, she did not avail herself of prenatal care and first saw an obstetrician when she was in labor.



Leslie Ann grew up in a deteriorating inner city neighborhood, the fourth of her mother’s six children by three different men. She denied physical or sexual abuse, but claimed that neither her mother, father, stepfather or her mother’s subsequent boyfriends had paid sufficient attention to her or her siblings.

She was raised partly by her oldest sister and partly by a neighbor down the hall. At age 14, she began experimenting with alcohol and drugs-marijuana, cocaine, and heroin-but soon stopped using heroin because she was afraid of contracting AIDS.



At that time, she lived occasionally in her mother’s apartment and most of the time on the street or with a friend. “I didn’t go to school. . . just sat around and got high,” she said candidly.

After she began using drugs, Leslie Ann met Terence, an 18 year-old drug dealer. She was attracted to him because he “didn’t tell me not to use drugs or try to change who I was,” she explained to the therapist.

Terence had a nice apartment and, at least initially, treated Leslie Ann well.



Approximately 3 months after meeting Terence, she became pregnant. The pregnancy was “definitely unplanned,” Leslie Ann said and her first impulse was to have an abortion. She procrastinated, however, until she was too far advanced for the procedure. Thus, the decision to have the baby was made by default. She reported that she did not enjoy being pregnant. The changes in her physical appearance distressed her and she experienced unpleasant physical symptoms, including morning sickness, back pains, and the exacerbation of several allergies.



Although Leslie Ann insisted she had tried to stay away from drugs during the pregnancy, she admitted that she was not successful. The drugs made her “feel better,” she said, especially when she became depressed about losing her shape. She reported that she had no fantasies about the baby while she was pregnant.

Instead,she focused on her own discomfort and looked forward to having the baby simply because the pregnancy would end. Labor and delivery were relatively easy, although Kevin was examined immediately because he was small for his gestational age.



Immediately after the birth, Leslie Ann said she became confused. “I needed to get high and didn’t think about the baby,” she noted as an explanation for leaving the hospital. After purchasing and smoking some crack, Leslie Ann did not return to the hospital because she thought there would be no point in doing so.


Addictions: DSM-IVAddictions: DSM-IV

AddictionAddiction (termed (termed substance dependencesubstance dependence by the by the American Psychiatric Association) is defined as a American Psychiatric Association) is defined as a maladaptive pattern of substance use leading to maladaptive pattern of substance use leading to clinically significant impairment or distress, as clinically significant impairment or distress, as manifested by three (or more) of the following, manifested by three (or more) of the following, occurring any time in the same 12-month period:occurring any time in the same 12-month period:

1. Tolerance, as defined by either of the following:1. Tolerance, as defined by either of the following:

(a) A need for markedly increased amounts of the (a) A need for markedly increased amounts of the substance to achieve intoxication or the desired substance to achieve intoxication or the desired effecteffect

oror

(b) Markedly diminished effect with continued use of (b) Markedly diminished effect with continued use of the same amount of the substance.the same amount of the substance.



2. Withdrawal, as manifested by either of the 2. Withdrawal, as manifested by either of the following:following:

(a) The characteristic withdrawal syndrome for the (a) The characteristic withdrawal syndrome for the substancesubstance

oror(b) The same (or closely related) substance is taken (b) The same (or closely related) substance is taken

to relieve or avoid withdrawal symptoms.to relieve or avoid withdrawal symptoms.3. The substance is often taken in larger amounts or 3. The substance is often taken in larger amounts or

over a longer period than intended.over a longer period than intended.4. There is a persistent desire or unsuccessful 4. There is a persistent desire or unsuccessful

efforts to cut down or control substance use.efforts to cut down or control substance use.



5.5. A great deal of time is spent in activities A great deal of time is spent in activities necessary to obtain the substance, use the necessary to obtain the substance, use the substance, or recover from its effects.substance, or recover from its effects.

6. Important social, occupational, or recreational 6. Important social, occupational, or recreational activities are given up or reduced because of activities are given up or reduced because of substance use.substance use.

7. The substance use is continued despite knowledge 7. The substance use is continued despite knowledge of having a persistent physical or psychological of having a persistent physical or psychological problem that is likely to have been caused or problem that is likely to have been caused or exacerbated by the substance.exacerbated by the substance.

Substance dependence may have with physiologic Substance dependence may have with physiologic dependence or no physiologic based on evidence of dependence or no physiologic based on evidence of tolerance or withdrawal.tolerance or withdrawal.



Substance abuseSubstance abuse is defined as a maladaptive pattern is defined as a maladaptive pattern of substance use leading to clinically significant of substance use leading to clinically significant impairment or distress as manifested by one (or impairment or distress as manifested by one (or more) of the following, occurring within a 12-more) of the following, occurring within a 12-month period:month period:

1. Recurrent substance use resulting in a failure to 1. Recurrent substance use resulting in a failure to fulfill major role obligations at work, school, or fulfill major role obligations at work, school, or home (such as repeated absences or poor work home (such as repeated absences or poor work performance related to substance use; substance-performance related to substance use; substance-related absences, suspensions, or expulsions from related absences, suspensions, or expulsions from school; or neglect of children or household).school; or neglect of children or household).

2. Recurrent substance use in situations in which it 2. Recurrent substance use in situations in which it is physically hazardous (such as driving an is physically hazardous (such as driving an automobile or operating a machine when impaired by automobile or operating a machine when impaired by substance use)substance use)



3. Recurrent substance-related legal problems (such 3. Recurrent substance-related legal problems (such as arrests for substance related disorderly as arrests for substance related disorderly conduct) conduct)

4. Continued substance use despite having persistent 4. Continued substance use despite having persistent or recurrent social or interpersonal problems or recurrent social or interpersonal problems caused or exacerbated by the effects of the caused or exacerbated by the effects of the substance (for example, arguments with spouse substance (for example, arguments with spouse about consequences of intoxication and physical about consequences of intoxication and physical fights).fights).


How do people become addicted?How do people become addicted?

1.1. Positive reinforcementPositive reinforcement• increases the likelihood that it will increases the likelihood that it will

occuroccur• e.g. inject heroin -> rush followed by e.g. inject heroin -> rush followed by

calm -> increased likelihood of another calm -> increased likelihood of another injectioninjection

• usually works better for fast acting usually works better for fast acting rather than slow acting drugs.rather than slow acting drugs.



2. Negative reinforcement: behaviour is 2. Negative reinforcement: behaviour is followed by a reduction of an aversive followed by a reduction of an aversive stimulusstimulus

e.g. depressed - > drink -> forget about e.g. depressed - > drink -> forget about depression (increases social behaviour) - depression (increases social behaviour) - > drink again> drink again

e.g. depressed -> shop for hours -> forget e.g. depressed -> shop for hours -> forget about depression -> shop againabout depression -> shop again

May partially account for withdrawal May partially account for withdrawal symptomssymptoms



Big Problem: Many addictions are Big Problem: Many addictions are resistant to extinction.resistant to extinction.

Also, simple learning models don’t Also, simple learning models don’t account for destructive and harmful account for destructive and harmful behaviour of addictsbehaviour of addicts Blatant disregard for the law, social norms, Blatant disregard for the law, social norms,

personal hygiene and healthpersonal hygiene and health



Dependence and withdrawal are not the Dependence and withdrawal are not the main obstacles to curing addiction.main obstacles to curing addiction.

Risk of Risk of relapserelapse is high: Cravings for the is high: Cravings for the drug persist for years or decades after drug persist for years or decades after dependence/ withdrawal symptoms subside.dependence/ withdrawal symptoms subside.

Not a simple case of reinforcement, but Not a simple case of reinforcement, but of some of some long-term, pathological learninglong-term, pathological learning resulting in maladaptive behaviour.resulting in maladaptive behaviour.


Mesocortical PathwayMesocortical Pathway

Different drugs target different Different drugs target different pathways, psychological effects vary.pathways, psychological effects vary.

But, the mesocortical pathway is But, the mesocortical pathway is activated for all addictive behaviours:activated for all addictive behaviours:

1.1. Ventral tegmental areaVentral tegmental area

2.2. Nucleus accumbens (ventral striatum)Nucleus accumbens (ventral striatum)

3.3. Amygdala (and hippocampus)Amygdala (and hippocampus)

4.4. Orbitofrontal/cingulate cortexOrbitofrontal/cingulate cortex All addictive behaviour increases All addictive behaviour increases

synaptic dopamine in the NAsynaptic dopamine in the NA



Mesocortical PathwayMesocortical Pathway

Dopaminergic pathway associated with Dopaminergic pathway associated with rewards for rewards for survival-relatedsurvival-related behaviours behaviours• Hunger, thirst, sexual arousalHunger, thirst, sexual arousal• Strong affective componentStrong affective component

Addictive drugs mimic the effects of Addictive drugs mimic the effects of natural rewardsnatural rewards

Motivation for drugs may supercede those Motivation for drugs may supercede those of natural stimuli because drugs produce of natural stimuli because drugs produce far greater levels of dopamine.far greater levels of dopamine.• Behave as if drugs are required for survival.Behave as if drugs are required for survival.


The Reward Prediction-Error The Reward Prediction-Error HypothesisHypothesis

Mesocortical pathway is not responsible Mesocortical pathway is not responsible for pleasure signal per sefor pleasure signal per se

Rather, neurons along this pathway fire in Rather, neurons along this pathway fire in the presence of cues that predict the the presence of cues that predict the onset of the reward onset of the reward (Shultz and colleagues).(Shultz and colleagues).

• DA neurons fire (phasic burst) prior to intake DA neurons fire (phasic burst) prior to intake of drug, or to unexpected rewardof drug, or to unexpected reward

• Cells are silent (no tonic activity) if reward Cells are silent (no tonic activity) if reward is withheldis withheld

““Craving” or “wanting” pathway: responds Craving” or “wanting” pathway: responds to cues to desireto cues to desire• Anticipation or prediction of rewardAnticipation or prediction of reward



Prefrontal areas responsible for drug-Prefrontal areas responsible for drug-related goal selectionrelated goal selection• Complex sequence of action planningComplex sequence of action planning• Pathological narrowing of goalsPathological narrowing of goals

Behaviour modified to provide maximum Behaviour modified to provide maximum exposure to cues for rewardexposure to cues for reward• ““Foraging” for drugsForaging” for drugs• May supercede regular feeding, or law-abiding May supercede regular feeding, or law-abiding behaviours behaviours



Temporal and other memory areasTemporal and other memory areas DA neurons innervating multiple targets, DA neurons innervating multiple targets, project widely throughout the forebrainproject widely throughout the forebrain

May account for context-rich, location May account for context-rich, location specificity of addictions (Shalev et al., specificity of addictions (Shalev et al., 2002).2002).• Rats show more addictive behaviours when in the Rats show more addictive behaviours when in the environment where drug was initially environment where drug was initially administered. administered.


CocaineCocaine

Powerful addictive stimulantPowerful addictive stimulant Two forms:Two forms:

1.1. Hydrochloride salt: powdered form which Hydrochloride salt: powdered form which dissolves in water and can be taken dissolves in water and can be taken intravenously or intranasally. intravenously or intranasally.

2.2. ““Crack” or “Freebase”: a compound that Crack” or “Freebase”: a compound that has not been neutralized by an acid to has not been neutralized by an acid to make the hydrochloride salt. make the hydrochloride salt. The freebase form of cocaine is smoked.The freebase form of cocaine is smoked.


CocaineCocaine

Dopamine agonist that directly binds to the dopamine Dopamine agonist that directly binds to the dopamine transporter in the VTA and NA (among other areas)transporter in the VTA and NA (among other areas)

Blocks the normal recycling process, resulting in a Blocks the normal recycling process, resulting in a buildup of dopamine in the synapse, which contributes buildup of dopamine in the synapse, which contributes to the pleasurable effects of cocaine.to the pleasurable effects of cocaine.

Results in a drastic increase of DA from the nucleus Results in a drastic increase of DA from the nucleus accumbensaccumbens

Buildup of dopamine in the synapse contributes to the Buildup of dopamine in the synapse contributes to the pleasurable effects of cocaine.pleasurable effects of cocaine.


Cocaine: Short Term EffectsCocaine: Short Term Effects

Affect: euphoric, energetic, talkative, Affect: euphoric, energetic, talkative, and mentally alert, especially to the and mentally alert, especially to the sensations of sight, sound, and touch. sensations of sight, sound, and touch. • Decreases the need for food and sleep. Decreases the need for food and sleep.

Physiological constricted blood vessels, Physiological constricted blood vessels, dilated pupils, and increased dilated pupils, and increased temperature, heart rate, and blood temperature, heart rate, and blood pressure. pressure. • Large amounts may also lead to bizarre, Large amounts may also lead to bizarre,

erratic, and violent behavior, including erratic, and violent behavior, including tremors, vertigo, muscle twitches, paranoiatremors, vertigo, muscle twitches, paranoia


Cocaine: Long Term EffectsCocaine: Long Term Effects

Psychological: Increasing irritability, Psychological: Increasing irritability, restlessness, and paranoia. restlessness, and paranoia.

• full-blown paranoid psychosis, in which the individual full-blown paranoid psychosis, in which the individual loses touch with reality and experiences auditory loses touch with reality and experiences auditory hallucinations.hallucinations.

Physiological: cardiovascular effects, (heart Physiological: cardiovascular effects, (heart rhythm and heart attacks), respiratory failure rhythm and heart attacks), respiratory failure

• Neurological effects: strokes, seizures, and headachesNeurological effects: strokes, seizures, and headaches

• Gastrointestinal effects: abdominal pain and nausea.Gastrointestinal effects: abdominal pain and nausea.

Combining cocaine and alcohol is highly toxic, and Combining cocaine and alcohol is highly toxic, and exacerbates long term effects. Most fatalities exacerbates long term effects. Most fatalities result from this mixture.result from this mixture.

Documents

PSY4080 D 6.0 Addictive Behaviours 1. PSY4080 D 6.0 Addictive Behaviours 2 Addictions A physical dependency to a substance results in withdrawal symptoms