Presentation on theme: "Addiction: Wise: Drug dependence-- cluster of cognitive, behavioral"— Presentation transcript:
1 Addiction:Wise: Drug dependence-- cluster of cognitive, behavioraland physiologic symptoms indicating the person hasimpaired control of drug use, and continues to use thedrug despite adverse consequences.Physical dep.-- adaptive state to the drug, with physicalwithdrawal symp.Psychol dep.-- “pleasure”, high---- pos. reinf.Neg. reinf.---- drug intake terminatesaversive effects of abstinence( withdrawal ).Craving-- memory
2 ADDICTIONSWise (1989, 1996): physical vs. psychological dependencetolerance, withdrawalPeriaqueductal gray (PAG), VTA, n. accumbens,raphe n., hypoth., amygdala, hippocampus, cingulate,prefrontal cortexEndogenous opiates (enkephalin, endorphin) –morphine, opium, heroin (mu, kappa, delta receptors)DA- cocaine, amphetamine, nicotine, caffeineMarijuana (THC)- anandamide( “internal bliss”), 2-AG, noladinether, virodhamine (4 ligands)Alcohol - “steady” vs. “binge”, somatization (girls)Blum et al (1990, 1996); Spear (2000):Reward deficiency syndromeNader et al. (2002)
3 Addicts become accustomed to high levels of dopamine, which plays an important role in the regulation of pleasure. Dopamine is manufactured in nerve cells within the ventral tegmental area and is released in the nucleus accumbens, limbic areas and the frontal cortex.
4 1. After being released into the synapse, dopamine binds to receptors on the next neuron. 2. Dopamine is either quickly reabsorbed (reuptake) or broken down by the enzyme monoamine oxidase (MAO).
5 Cocaine blocks reuptake of dopamine plus added release Cocaine blocks reuptake of dopamine plus added release. As a result, dopamine accumulates in the synapse, where it stimulates the receiver cell.
6 Amphetamines stimulate excess release of dopamine, overwhelming the processes of reuptake and enzymatic breakdown.
7 Nicotine stimulates the release of dopamine, while another substance in cigarette smoke blocks the action of MAO.
8 5-HT – in hypothalamus from raphé n. Reward-Deficiency-Syndrome(Blum et al., 1996)ICSS cascade: DA – VTA to n. accumbens, amygdala, hippocampus, septum, cingulate, prefrontal cortex5-HT – in hypothalamus from raphé n.Enkephalin – in VTA from hypothalamus, in n. accumbensGABA – in VTA, n. accumbensGABAa/BZD - in amygdalaBZD = Benzodiazepine
10 Spear (2000): Reward-deficiency syndrome in adolescence. Nader et al. (2002): D2 activity and social status in monkeys.ICSS & ADDICTION---- Rev.Olds, Delgado, Deutsch, Stein, Crow, Gallistel,Gibson et al., Rolls, Shizgal, Wise, Stein & Belluzzi,Henry, Blum et al., Spear, Nader et al.Video: Addiction