Neuroscience and Clinical Semester 1 Week 9: Substance use disorders Flashcards
Evolution of labels of SUD
‘addiction’ → ‘dependence’ → distinction between substance ‘abuse’ and ‘dependence’ → combined ‘abuse’ and ‘dependence’ into single diagnosis of SUD (in the DSM 5)
What is addiction?
Someone is addicted if they continue to use drugs despite a sincere intention to do otherwise. - (Heather, 2017)
DSM-5 diagnostic criteria for alcohol use disorder
Problematic pattern of alcohol use leading to clinically significant impairment or distress, as manifested by at least two of the following within a 12 month period:
- Alcohol taken in larger amounts or over a longer period than intended.
- Persistent desire or unsuccessful attempts to cut down alcohol use.
- Great deal of time spent in activities to obtain or use alcohol, or recover.
- Craving.
- Recurrent alcohol use resulting in failure to fulfill major role obligations.
- Continued alcohol use despite social problems caused by it.
- Important social, occupational or recreational activities sacrificed in favour of drinking.
- Recurrent alcohol use in situations where it is hazardous.
- Continued alcohol use despite knowledge of damage to health.
- Tolerance (either increased amounts used or diminished effect of same dose).
- Withdrawal (either presence of withdrawal syndrome, or alcohol is used to avoid withdrawal effects).
Three severity categories: mild (2-3 criteria), moderate (4-5 criteria), severe (6 or more criteria)
Limitations of the DSM-5 criteria for substance abuse
- Criteria doesn’t really tell us what SUD is
- Across all severity categories, there are 2036 possible combinations of symptoms. Even in the moderate category it’s possible to have 2 people with no shared diagnostic criteria.
Global prevalence of alcohol use disorder
Women: Most common in North America, some areas in South America, Australia, Russia, Scandinavia
Men: Most common in South America, UK, Russia, China
Global prevalence of drug use disorder
Women: Most common in USA, South America, UK, Middle East, some countries in Africa
Men: Most common in USA, South America, Middle East
Global prevalence of tobacco smoking
Women: Most common in Europe
Men: Most common in Russia, Asia, some countries in South America
Risk factors of SUDs
SUDs are more common in people who have also been diagnosed with another disorder e.g. depression
↳ hard to establish whether one causes the other
Twin studies: Across all SUDs, heritability estimates range between 30% and 70%
↳ definitely a heritable component to most addictions
Traumatic life events: Traumatic life events, particularly sexual abuse during childhood, associated with marked increase in risk for development of SUD.
Psychological theories of SUD
Operant conditioning
Compulsion
Brain disease
Habits
Dual-process theory
Explanation 1: Operant conditioning
People take drugs because of the outcomes they produce:
To get ‘high’ -> heroin, cocaine, MDMA, alcohol
To increase alertness and reduce fatigue -> nicotine, caffeine
Social facilitation -> alcohol, MDMA, cocaine
To alleviate distress -> alcohol, heroin, nicotine
Drugs used as an operant behaviour:
A voluntary behaviour that is maintained by its consequences
↳ However, the defining characteristic of addiction is that a person continues to use drugs, even though the positive effects are diminished and negative effects have increase
Explanation 2: Compulsion
Compulsive drug use - explains addictive behaviour when the negatives outweigh the positives. Addicts are ‘compelled’ to use the drug.
↳ Why? - addiction is a brain disease
Explanation 3: brain disease
Brain disease - disruptions to the dopamine reward system
Addicted brains are hypoactive and have less grey matter in prefrontal regions
Could be linked to brain development as many start substance abuse in adolescence
↳ However:
Some studies found that abnormal brain function precedes (and is a risk factor for) addiction in later life - Zilverstand et al (2018)
Some of these brain changes mirror those seen when highly rewarding behaviours are repeated e.g. in the context of romantic love (fischer et al) - not necessarily specific to substance abuse
Explanation 4: Habits
- Seeing stimulus evokes expectation of outcome which then causes them to perform the response
- associative learning - direct link between stimulus and response - bypasses any mental processes
- anticipated outcome may still be there but it’s less important
- Evidence: In laboratory animals, drug-seeking becomes habitual: it persists despite negative consequences.
Explanation 5: Dual-process theories
- Originates with controlled cognitive processes (outcome expectancies etc.)
- Overtime, these become automatic cognitive processes
- Evidence: retraining of these cognitive processing biases is suggested to be an effective treatment
Does choice play an important role in addiction?
- Motivation to change is one of the best predictors of recovery (Prochaska et al., 1992)
- Motivational interviewing, a treatment that resolves ambivalence and increases motivation to change, is effective (Miller, 1996).
- Drug use is sensitive to economic factors, such as changes in price (Petry & Bickel, 1998)
- Contingency management, in which people receive small incentives if they have not used drugs, is an effective treatment for SUD (Higgins, 1994).
What is remission?
when someone used to meet diagnostic criteria for addiction but no longer do
What does treatment for SUD aim to do?
- Reduce the motivation to use the drug
AND / OR - Increase the motivation to abstain (or reduce use)
AND / OR - Provide people with the resources that they need to change their behaviour
What treatments are there for SUD?
Talking therapy
Self-help groups
Contingency management
Pharmacotherapy
Treatment 1: Talking therapy
- Recognise the unrealistic beliefs that are maintaining drug use and improving coping skills
- Motivational interviewing - people are in treatment because they actually want help, this helps them think about all the benefits of stopping - change in language
Treatment 2: Self-help groups
- Help people achieve and maintain abstinence
- Increases self-efficacy and brings about changes in social networks (e.g. new friends who all don’t drink)
Treatment 3: Contingency management
Financial payments for clear drug samples
Treatment 4: Pharmacotherapy
- Various prescribed drug treatments
- Smoking: nicotine patches, Varenicline (alleviates withdrawal), bupropion (antidepressant), vaping
- Heroin: methadone/buprenorphine (substitutes)
- Alcohol: Naltrexone (blocks effects), acamprosate (improves withdrawal), disulfiram (prevents metabolism of alcohol - you become ill when drinking)
