Drugs & Consciousness Fig Neuroadaptation is not the same as drug tolerance; in the former, brain chemistry is adapting to offset the drug, while in the latter, more drug is needed with each repeated exposure. Addiction must be compulsive, with adverse physiological consequences; removal of the substance will result in withdrawal. Consider the opposite: Attributing serial adultery to a 'sex addiction' does not explain the sexual impulsiveness. (Radford, 2010). Table 10.1 will be on the next exam. Table 10.2 will be on the next exam.

Drugs & Biology Adopted individuals are more susceptible to alcohol dependence if a biological parent has a history of alcohol abuse. Having an identical twin (rather than a fraternal twin) increases risk of alcohol dependence. (Kendler et al. 2002). Researchers have identified genes common among people predisoposed to alcohol dependence, and are seeking genes for tobacco addiction (Numberger & Bierut, 2007). These genes appear to produce deficiencies in the dopamine reward system. While triggering temporary dopamine-produced pleasure, these drugs disrupt the normal dopamine balance. Make note of this for Web Article 3: PKM-Zeta may be one of these anti-addiction drugs.

Drugs & Biology Alcohol is a morphoid agonist, with the added feature that the compound does not get created prior to crossing the blood-brain barrier. It is a sedative that slows neural processing. Alcohol disrupts memory formation at the synapses, in the hippocampus, which is the most sensitive and easily damaged part of our brain (and the newest in terms of evolution). Alcohol suppresses REM sleep. Fig 10.2 Alcohol dependence shrinks the brain. Alcohol produces 'myopia'; it focuses attention on an arousing situation, and distracts attention from normal inhibitions. (Giancola, 2010). Opiates are endorphin agonists, causing withdrawal.

Drugs & Biology Nicotine Fig Nicotine reaches the brain in 7 seconds, twice as fast as intravenous herion. Nicotine releases a flood of neurotransmitters: epinephrine and norepinephrine diminish appetite and boost alertness and mental efficiency; dopamine and opoids calm anxiety and reduce sensitivity to pain. Cocaine: see Fig. 10.5: By binding to a site that normally reabsorbs neurotransmitter molecules, cocaine blocks the reuptake of dopamine, norepinephrine, and serotonin. The extra neurotransmitter molecules remain in the synapse, intensifying their normal mood altering effects and producing a euphoric rush. When the cocaine level drops, the absence of these neurotransmitters produces a crash.