Substance Use & Addictive Disorders (PSY3142 A, Fall 2023) PDF

SUBSTANCE USE & ADDICTIVE DISORDERS PSY3142 A FALL, 2023 AGENDA • Dependence • Explanations of drug use • Reward and the evolutionary context • Theories • Neurobiology and neurochemistry of dependence • Notes about treatment "Prisoner of drugs" Art by: Sebastian Eriksson Author Description: “Pris...

SUBSTANCE USE & ADDICTIVE DISORDERS PSY3142 A FALL, 2023 AGENDA • Dependence • Explanations of drug use • Reward and the evolutionary context • Theories • Neurobiology and neurochemistry of dependence • Notes about treatment "Prisoner of drugs" Art by: Sebastian Eriksson Author Description: “Prisoner of drugs” Drug addiction is like being stuck in prison behind bars, where you can’t 2 easily escape from. Heroin is the worst form of addiction because it often leads to death. Source: Addiction - The Trauma & Mental Health Report (yorku.ca) DEPENDENCE DEPENDENCE/ADDICTION/DISORDER • Individual predisposition to consume a drug • Development of tolerance • Withdrawal symptoms upon removal • Cravings • Chronic , relapsing disorder: great likelihood of relapse after consumption ceases 4 DEPENDENCE Some people continue using a drug to avoid withdrawal = physical dependence ➢Drugs with strong withdrawal symptoms tend to have a high risk for physical dependence. • Operant conditioning supports both drug use and dependence • Drug use often supported by positive reinforcement • +feelings = continued use (but sometimes removal of negative symptoms which is -reinforcemnt) • Dependence supported by negative reinforcement • Removes negative withdrawal symptoms = continued use 5 DEPENDENCE Some people continue using a drug to experience the pleasurable effects of the drug = psychological dependence ➢Drugs with strong rewarding effects tend to have a high risk for psychological dependence • Operant conditioning supports both drug use and dependence • Drug use often supported by positive reinforcement • +feelings = continued use • (but sometimes removal of negative symptoms which is -reinforcement) • Cravings (intense preoccupation, strong desire/urge to consume a drug) are thought to be associated with environmental drug conditioned cues supported by classical and operant conditioning. 6 • Can encourage drug use • Can trigger relapse in someone who has stopped using a drug for some time DEPENDENCE IT CAN BE ONE IT CAN BE BOTH IT CAN CHANGE 7 DSM CRITERIA SUBSTANCE USE DISORDER A maladaptive pattern of substance use, leading to clinically significant impairment or distress, as manifested by three (or more) of the following, occurring at any time in the same 12-month period. 8 Various criteria related to • Impaired control • Risky use • Social impairment • Pharmacological Drug use ≠ substance disorder/dependence/addiction/abuse DSM CRITERIA FOR ABUSE A. A maladaptive pattern of substance use leading to clinically significant impairment or distress, as manifested by 1 (or more) of the following, occurring within a 12-month period: 1. recurrent substance use resulting in a failure to fulfill major role obligations at work, school or home (e.g., repeated absences or poor work performance related to substance use; substance-related absences, suspensions or expulsions from school; neglect of children or household) 2. recurrent substance use in situations in which it is physically hazardous (e.g., driving an automobile or operating a machine when impaired by substance use) 3. recurrent substance-related legal problems (e.g., arrests for substance-related disorderly conduct) 4. continued substance use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the substance (e.g., arguments with spouse about consequences of intoxication, physical fights) B. The symptoms have never met the criteria for substance dependence for this class of substance. WHAT PROMOTES DEPENDENCE? Drug factors: • Some drugs promote dependence more than others • Due to their strong positive or negative reinforcing properties • Some routes of administration or ways of ingesting a drug can promote dependence more than others • Due to the speed of achieving high drug concentration • Frequent use promotes dependence 10 • Repeated use supports/strengthens conditioning and can promote dependence IND IVID UAL FACT ORS T HAT PROM OT E D EPEND ENCE 11 SOME LAST TAKEAWAYS • Any brain can become dependent on drugs • Being raised in a supportive environment that promotes good mental health that continues throughout life with supportive, and non-drug using peers, they will be less vulnerable to drug dependence • If someone does not ever use drugs, they will not develop drug dependence even with a vulnerability to it 12 MODERN EXPLANATIONS OF DRUG USE 13 MODERN BEHAVIORAL EXPLANATIONS OF DRUG USE • Conditioned taste aversion • Animals won’t do drugs if they taste bad • Only human can become addicted (disproven) • Positive reinforcement model • Positive reinforcer is any stimulus that increases the frequency of a behavior it is contingent on. SELFADMINISTRATION • The similarity between the patterns of self-administration of ethanol in a human and a rhesus monkey under continuous drug availability. The arrows indicate the occurrence of withdrawal symptoms. REINFORCEM ENT AND T HE T EM PORAL ISSUE Immediate consequences are generally more powerful than delayed consequences. Self-control involves choosing the larger later reinforcer over the smaller sooner reinforcer We are also tend to avoid/delay punishing consequences even if delay may lead to a larger later punisher ….often difficult to overcome these tendencies! 16 IT ISN’T A SIMPLE CHOICE! • Example: • Choosing not to smoke leads to both • a smaller sooner punisher in the form of withdrawal symptoms and • a larger later reward in the form of improved health. • Continuing to smoke leads to both • a smaller sooner reward in the form of a nicotine high and • a larger later punisher in the form of deteriorating health. REWARD AND EVOLUTION 18 REWARD • Reward has two independent processes: wanting (incentive) and liking (evaluation of pleasure) • Usually, wanting and liking occur together but this is not always the case • Robinson and Berridge (2008) • Wanting and liking have separable neural systems • Wanting: Involves dopamine • Liking: Involves opioid and benzodiazepine-GABA systems EVOLUTIONARY CONTEXT OF REWARD • Reward may be a mechanism that evolved to help increase the adaptive fitness both of the entire species and of individual members of a species EVOLUTIONARY CONTEXT 21 MODERN HUMAN INGEST SUBSTANCES THAT STIMULATE THE SYSTEM SENSATION OF PAYOFF WITHOUT BEHAVIOUR 22 SOME THEORIES 23 EVOLUTIONARY GAME THEORY Quantitative model derived from strategies used by animals to optimize survival and reproductive fitness Human=self-perceived fitness Tricks the system to equate drug consumption with benefit to fitness 24 INCENTIVE SENSITIZATION THEORY • Repeated drug use may cause sensitization of incentive motivation to seek out the drug and this change may underly drug dependent behaviour. • Initial drug use = drug acts as a reinforcer (but not necessarily stronger than other competing nondrug reinforcers that influence behaviour) • Repeated drug use = drug acquires increased reinforcing properties; becomes a very strong reinforcer and having increased influence, controlling large amounts of on behaviour Craving as a manifestation of incentive salience (toward drug associated stimuli) Sensitization may be long lasting supporting drug dependence as chronic HEDONIC DYSREGULATION AND ADAPTATION • CONTINUALLY SHIFTING BALANCE BETWEEN REWARD AND ANTIREWARD SYSTEMS • SIMILAR TO COMPENSATORY PROCESSES (A, B PROCESSES) • EXTENDED DRUG USE DYSREGULATES THE BRAIN REWARD/ANTIREWARD SYSTEMS DRIVES INCREASED DRUG USE TO OVERCOME LOW MOOD AND CHASE 26 THE INITIAL HIGH NEUROSCIENCE OF DEPENDENCE NEUROBIOLOGY: MEDIAL FOREBRAIN BUNDLE • Large collection of axons extend from the hypothalamus to the septum • Accidental discovery in 50s Olds & Milner • Rats with electrode placement would self-administer until exhaustion up to 2000 x/hour! 28 Figure 12.29 Mesolimbic dopamine system NEUROBIOLOGY: NUCLEUS ACCUMBENS • • • • Key brain structure driving addiction Turns a neutral stimulus into a desirable one Receives direct messages from the DA rich VTA Input from amygdala, hippocampus, MPFC NEUROBIOLOGY: ORBITOFRONTAL CORTEX • Prefrontal cortical region • Reciprocal connection with NAC • Projections from amygdala and hippocampus • Maintenance of addiction 31 NEUROANATOMY OF THE CYCLE OF DRUG DEPENDENCE • Binge/intoxification phase • NAC & dorsal striatum • Withdrawal • Extended amygdala • Craving/cognitive preoccupations • Basolateral amygdala – conditioning functions • Hippocampus – contextual processing • Prefrontal cortex – executive control NEUROCHEMISTRY Drug Neurochemical action Psychological Effect Cocaine Inhibit DA transporters = increase DA in synapse Pleasure Hyperactivity Opiates Stimulate OP receptor; inhibits GABA release = increase DA Relief from pain Pleasure Amphetamines Stimulates release of monoamines (incl DA) Pleasure Hyperactivity Ethanol Increases GABA receptor function; inhibits NMDA glut receptor function; increases DA release Reduced anxiety Euphoria Disinhibition Nicotine Facilitates nicotinic acetylcholine receptors; increases release of DA Relaxation Pleasure Cannabinoids Stimulates cannabinoid receptors; triggers release of DA Relaxation Mild hallucinations Pleasure Ecstasy Increases synaptic 5-HT levels; prolonged 5-HT depletion b/c blocked 5-HT uptake; promotes DA release and decreases in reuptake Heightened pleasure Boost self-confidence Feelings of extroversion DOPAMINE HYPOTHESIS • Most drugs of abuse increase DA release somewhere along the mesolimbic pathway EVIDENCE THAT MESOLIMBIC DOPAMINE SYSTEM IS INVOLVED IN REWARD: • Dopamine is released during intracranial self-stimulation • Drugs that enhance dopamine release increase self-stimulation, whereas drugs that decrease dopamine decrease self-stimulation • Levels of dopamine increase when animals engage in behaviors such as feeding and sexual activity • Highly addictive drugs such as nicotine and cocaine increase the level of dopamine in the nucleus accumbens ACETYLCHOLINE HYPOTHESIS • Acetylcholine neurons in NAC may be involved with aversion • Proposed as a counterbalancing function • Brain’s ability to turn off pleasurable activities NEUROCHEMICALS INVOLVED WITH WITHDRAWAL PHASE Neurochemical Relative change during withdrawal Withdrawal symptom Dopamine Decrease Dysphoria Opioids Decrease Pain, dysphoria Serotonin Decrease Pain, dysphoria, depression GABA Decrease Anxiety, panic attacks CRH Increase Stress Norepinephrine Increase Stress Glutamate increase hyperexcitability STRESS AND DEPENDENCE STRESS RESPONSE AND STRESS HISTORY = IMPORTANT DETERMINANTS OF DRUG ABUSE • Stress, both present and past, increases the strength for reinforcing stimulus. BOTH DRUGS AND STRESS INCREASE DA ACTIVITY IN NAC 38 NOTES ABOUT TREATMENT 39 TREATMENT • Treatment has shifted form focusing on moral default to medical model • Various treatment options are well described in the text, please review and familiarize yourself with these • Recovery can take much time and effort with some defining it as a chronic relapse disorder • Pharmacotherapy 40 STIGMA People who use drugs, especially those struggling with addiction face discrimination and barriers to getting help. Stigma can: • lead a person to avoid getting help because they are afraid of judgement or getting in trouble with work, their loved ones or even the law You can: • cause a person to hide their drug use or use drugs alone • use person-first language, for example say 'person who uses drugs' instead of 'drug user’ or slang such as "addict" or "junkie” • Promote diminished sense of self-worth, selfesteem, shame • use neutral, medically accurate words when describing drug use • affect a person's ability to find housing and jobs, which affects their health and quality of life 41 Stigma around drug use - Canada.ca • contribute to people who use drugs receiving a lower quality of care from the healthcare system when they access services • use language that shows care and concern, rather than judgement • speak up when you hear someone being treated or talked to in a disrespectful way PLEASE TAKE 10 MINUTES TO READ AND REFLECT ON THE ARTICLE IN THE LINK • 'My way out': Patient lives are changing with Sudbury addiction unit's novel approach (cbc.ca) • You may also be interested in some articles in a recent series on addiction The Way Out: A CBC Calgary series on addiction in Alberta | CBC News 42 • • • • • • SUMMARY 43 Dependence Explanations of drug use Reward and the evolutionary context Theories Neurobiology and neurochemistry of dependence Notes about treatment