Recently some states have moved to legalize the possession and use of small amounts of marijuana. Do you support this movement? Why or why not? Can you think of some unintended consequences of such policy changes?
If everyone has a “different” personality (i.e., if no two are alike), then how can we say that someone has a “disordered” or “sick” personality? What truly makes a personality pathological?
Nicotine, which was introduced in the French court t in the 16th century is what gives smoking its pleasurable qualities. About 30% of all Americans smoke, which is down from 4 2.4 % who were smokers in 1965. Nicotine in small doses stimulates the central nervous system, but may also relieve stress and improve mood. It can also cause high blood pressure, heart disease and cancer. High doses blur vision, cause confusion, lead to convulsions and sometimes death.
Caffeine Use Disorders
Caffeine is called the “gentle stimulant” and is used regularly by 90% of Americans. This drug is found in tea, coffee, cola drinks, and cocoa products. In small doses, caffeine can elevate mood and reduce fatigue, but larger doses can produce jitteriness and insomnia.
Regular caffeine use can result in tolerance and dependence. Withdrawal symptoms include headaches, drowsiness, and a generally unpleasant mood. Caffeine’s effect on the brain appears to involve the neurotransmitters adenosine and to a lesser extent serotonin Caffeine block adenosine reuptake.
Biological Causes of Substance-related Disorders
Evidence suggests that substance abuse has a genetic component. Twin, family, and adoption studies indicate that certain people may be genetically vulnerable to drug abuse. Most genetic data on substance abuse comes from research on alcoholism.
Both twin and adoption studies suggest genetic factors play a role in alcoholism, particularly in males. Two studies have located genes that may influence alcoholism on chromosomes 1, 2, 7, and 11, plus a finding that a gene on chromosomes 4 may serve to protect people from becoming alcohol dependent. The field of functional genomics focuses on how genes work to influence addiction.
The pleasurable experience reported by people who use psychoactive substances partly explains why people continue to use them. In effect, people are positively reinforced for using drugs. All drugs seem to affect the reward or pleasure centers of the brain. The pleasure center is believed to include the dopaminergic system and its opioid-releasing neurons that begin in the midbrain ventral tegmental area and then work their way through the nucleus accumbens a region in the basal forebrain rostral to the preoptic area of the hypothalamus) and on to the frontal cortex.
Amphetamines and cocaine (including nicotine and alcohol) act directly on the dopamine system, whereas other drugs increase the availability of dopamine indirectly. GABA, as a major inhibitory neurotransmitter system, helps to turn off the continued activity of the reward system. Opiates inhibit GABA from doing its job, which in turn stops the GABA neurons from inhibiting dopamine, thus making more dopamine available from inhibiting dopamine, thus making more dopamine available in the reward center.
With several drugs, negative reinforcement is related to the drug’s anxiolytic effect, particularly alcohol. Such drugs reduce anxiety via the septal/hippocampal system, which includes a large number of GABA sensitive neurons. Such drugs may enhance the activity of GABA in this region, thereby inhibiting the brain’s normal reaction (anxiety/fear) to anxiety-producing situations.
The personality disorders represent long-standing and ingrained ways of thinking, feeling, and behaving that can cause significant distress. Because people may display two or more of these maladaptive ways of interacting with the world, considerable disagreement remains over how to categorize personality disorders.
DSM-5 includes 10 personality disorders that are divided into three clusters: Cluster A (odd or eccentric) includes paranoid, schizoid, and schizotypal personality disorders; Cluster B (dramatic, emotional, or erratic) includes antisocial, borderline, histrionic, and narcissistic personality disorders; and Cluster C (anxious or fearful) includes avoidant, dependent, and obsessive-compulsive personality disorders.
Cluster A Personality Disorders
People with paranoid personality disorder are excessively mistrustful and suspicious of other people, without any justification. They tend not to confide in others and expect other people to do them harm.
People with schizoid personality disorder show a pattern of detachment from social relationships and a limited range of emotions in interpersonal situations. They seem aloof, cold, and indifferent to other people. People with schizotypal personality disorder are typically socially isolated and behave in ways that would seem unusual to most of us. In addition, they tend to be suspicious and have odd beliefs about the world.