session 14 Flashcards
Physiology of Addiction
The nucleus accumbent responds strongly to reinforcing stimuli. A midbrain structure gives rise to dopamine pathways
- causes “wanting” more than “liking”
Tolerance
needing more of the drug to achieve a high
Withdrawal
causes a physical feeling of discomfort when the drug is absent from the system
Genes for Addiction
genes that correlate with alcoholism, genes that…
-predispose them to higher levels of stress and anxiety
-produce less dopamine
-lead to poor risk management
Genes for prevention
genes that make metabolizing alcohol difficult
-become hungover almost immediately, rarely abuse alcohol
“Antabuse”
pill that immediately causes symptoms of being hungover
-can be used to curb alcoholism
-only as effective as willpower, must be taken routinely
-placebo just as effective
Methadone
a drug that helps with opioid addiction
-“time-release” heroin
-provides a low-level drug to prevent withdrawal
-no risk of overdose
-helps physical dependence, not psychological dependence
clinical depression
lack of happiness than an increase in sadness, feelings of lethargy, worthlessness, helplessness
Physiology of depression
-some evidence of different versions of serotonin transporters and how they mediate response to stressful events
-no evidence of specific genes that consistently cause the disorder
Tricyclic Antidepressants
first anti-depressants blocks the reuptake of serotonin, dopamine, and norepinephrine into the presynaptic neuron
-many side effects
-block some acetylcholine and histamine
Monoamine Oxidase Inhibitors (MAO-Is)
breaks down and inactivates the catecholamine family of neurotransmitters
-DANGEROUS, last resort
-patients have to avoid foods containing tyramine
- leads to unsafe rises in blood pressure
Selective Serotonin Reuptake Inhibitors (SSRI’s)
-most common anti-depressants
-focuses only on the reuptake of serotonin at certain receptor sites
-generally safer, fewer effects
neurotrophins
released early in the nervous system development in response to activity-allow synaptic strengthening and survival
Brain-derived neurotrophic factor (BDNF)
increased activity from all of the extra neurotransmitters present following anti-depressant use also triggers the release of a lot of BDNF
-leads to new neuronal growth in the hippocampus, which can facilitate new learning
Schizophrenia
0.5%-1% worldwide, more common in cities, and more common in males
-“schism” between patient and others
-deterioration of function for at least six months
-positive symptoms (hallucinations, delusions, disorganized speech)
-negative symptoms (social withdrawal, lack of appropriate emotional affect)
Schizophrenia Genetics
-more likely than with most psychological disorders
-a 50% concordance rate between identical twins
-pre-natal environment very important (drug use, malnutrition, season-of-birth)
seritonin
the most implicated in depression
the therapeutic effect of anti depressants may result from triggering the release of what?
BDNF
Neurodevelopmental hypothesis
holds that schizophrenia is the result of genetic predispositions, poor prenatal environment, and environmental stressors
Antipsychotic Drugs
Neuroleptic (antipsychotic) drugs effectively elimate postive symtoms of schizophrenis
-block dopamine receptors
Dopamine hypothesis of Schizophrenia
supported by the fact that heavy amphetamine use (which releases lots of dopamine) can make people temporarily act schizophrenic
Glutamate Hypothesis
excess dopamine inhibits glutamate, and vice versa, reductions in PFC glutamate could explain attentional problems in schizophrenia
Tardive dyskinesia
unwanted, repetitive muscles movements, which makes sense considering that the drugs block dopamine
