Substance Use DisordersDSM-IV has two separate categories of substance use disorders:A. Substance Dependence - What we typically think of as “addiction”- Involves physiological dependence, withdrawal symptoms- Use is frequent, interferes with functioning, but they can’t stop usingB. Substance Abuse- Less severe than dependence- Use is typically sporadic, but causes functional impairmentLifetime Prevalence of substance-related diagnoses:- Nicotine 24%- Alcohol 14% (20% male; 8% female)- Illicit drugs 6%Effects of Alcohol- It affects 3 major neurotransmitters: glutamate, GABA, dopamine- Reduces rate of neural firing in frontal cortex, cerebellum (glutamate & GABA)- Increases rate of dopamine activity, especially in brain’s reward centers- Effects vary by blood alcohol concentration:.05% slight “buzz”, decreased inhibition & judgment.10% moderate motor incoordination, slowed reactions.20% decidedly intoxicated; severe motor & sensory deficits.35% surgical anaesthesia.40% breathing impaired/coma .50% death from organ failure- Alcohol implicated in 50% of traffic fatalities and violent crimes- Korsakoff’s syndrome (vitamin B1 deficiency)- Liver cirrhosis- Brain damage – atrophy over time in frontal cortex, hippocampus, cerebellum- Fetal brain damage – even with 1.5 drinks per week in pregnancy- Depression co-morbidity (>25%)Alcohol Dependence Subtypes: Type I versus Type IIType I = socially anxious, drinking to self-medicateType II = antisocial (violate social norms)What causes alcohol abuse/dependence?A. Biological factors:1) Alcohol more reinforcing for some individuals- Dopamine receptors (D2) – genetics, childhood abuse/neglect- When addicted, low dopamine response to everyday highs2) Toxic metabolites (acetaldehyde) more “punishing” for some3) “AA Model” – alcoholism as uncontrollable diseaseB. Sociocultural factors – cultures vary dramatically in % alcohol use problemsC. Personality factors – two risks: antisocial or neurotic (trait anxious)Treatments for Alcohol Use Problems:- 10% of those with problems enter treatment per year- 50% dropout rate- 30% of completers recovered at 1-year follow-up (abstinent)- Among alcohol abusers, high spontaneous recovery ratePharmacological interventions:- Naltrexone (Vivitrol injection)- Antabuse- Prometa (targets GABA)- Alcohol/drug vaccines (!)Alcoholics Anonymous (AA)- Little systematic research (they don’t release records)- Available data: 25-50% success at 1 year (probably about same as CBT)_______________________________________________________________________Other Important Points:1) Diagnosis of abuse/dependence requires functional impairment;2) Thus, occasional binge drinkers (aka, ‘college students’) usually don’t meet diagnostic criteria.3) Most alcohol abusers don’t progress to alcohol dependence (majority of college-age abusers no longer diagnosable in 30s)4) AA model: Alcoholism = disease (generally applicable to dependence, not abuse) AA (12-step program): heavily spiritual (“higher power”)Drugs of Abuse/AddictionEvery culture has had an array of drugs/substances used to induce changes in mood, thought, and behavior. Major classes of addictive drugs: Hallucinogens (psychedelics) Stimulants Narcotics (opioids) Depressants (anti-anxiety)Addictive drugs target brain’s reward centers: nucleus accumbens, hypothalamus, VTA.A. Hallucinogens (marijuana, ecstasy, LSD, “shrooms”, PCP) 1) Marijuana (THC)- targets opioid receptors in brain’s reward centers (anandamide = “bliss”)- also affects frontal cortex activity; hippocampus; cerebellum- cognitive effects (short-term memory, attention, mental flexibility, motor)- “amotivational syndrome” (absorption with present; reduced achievement)- fairly low addictive potential (little tolerance, moderate withdrawal) Marijuana versus Alcohol: a. Potential for lethal overdose: Alcoholb. Long-term brain damage: Alcoholc. Greater addiction potential: Alcohold. Damage to developing fetus: Alcohole. Driving impairment: Alcoholf. Violence trigger: Alcoholg. Damage to major organs: Alcohol 2) Ecstasy (MDMA) – hallucinogen and stimulant- Originally called “empathy” (oxytocin boost  attachment)- Enhanced sensory awareness (serotonin: sensory integration)- Neurotoxic effects: damage to serotonin-using neurons (temperature-dependent?)3) LSD (Lysergic acid diethylamide)- Blocks some serotonin activity (5HT2A agonist)  increased dopamine- Altered sensory perception- synaesthesia (seeing sounds, feeling colors, etc.)B. Stimulants: (amphetamine, cocaine, meth)- Stimulates release of dopamine, blocks reuptake- Energizing- short-term increase in frontal cortex activity- long-term frontal damage- Amphetamine psychosis- Potently addictive (about 1 in 6 who try)- Relatively poor long-term prognosis in stimulant dependence- Nicotine: stimulant and depressant, extraordinarily addictiveSmoking cessation: about 15% success rate over one year.C. Narcotics (Codeine, Morphine, Heroin)- Directly target brain’s reward centers (opioid system)- Also reduce pain (physical and emotional)- At high doses, turns off respiratory control centers in brain- Naltrexone particularly effective for narcotic