Archive for category Medical Consequences'

Adolescence and Drug Abuse: Biomedical Consequences

Many facets of the biomedical aspects of substance abuse in adolescents have not yet been adequately researched. Little is known about the biological elements, if any, that contribute to the genesis of substance abuse. In the instance of alcoholism a genetic vulnerability appears to be established from the studies of identical twins, one raised by the natural parent and the other placed at an early age in the home of nonalcoholic foster parents. In the studies conducted both in this country () and in Denmark () the incidence of problem drinking of both groups of twins was similar. It is well established that among people of Mongolian descent, a widespread sensitivity to alcohol, based upon the rapid accumulation of acetaldehyde, is observed (). Facial flushing and more upsetting symptoms, including asthma and hypotension, can be present. In those with marked discomfort after drinking small amounts of ethanol, a certain preventive role is probably played by this inborn racial change in the ability to metabolize alcohol. Such genetic factors have not yet been uncovered for other psychoactive drugs. With the recent identification of opiate () and benzodiazepine () receptor sites, and the hint that other drug-specific Read more […]

The Neuropsychological Consequences of Alcohol and Drug Abuse

The research and popular literature are replete with information discussing the physical mechanisms of addiction, theories of alcohol and drug action within the human body, and the psychosocial impact of substance abuse. We are gaining insight into the process of addiction and how the rewarding effects of certain substances are a result of dysregulation of the brain reward circuit. However, the body of research linking the physical effects of substances of abuse to cognitive or neuropsychological functioning is less comprehensive. We are beginning to comprehend how physical changes in the brain due to substance abuse may lead to acute, transient, and permanent alterations in the way one thinks and processes information. The purpose of this chapter is to provide the reader with a survey of research identifying the documented relationships between alcohol and drug abuse and neuropsychological functioning. Clearly, a significant portion of the research in this area has focused on alcohol abuse and this chapter will begin with an understanding of that body of research. Next will be a review of the research on polydrug abuse in which population samples are not distinguished by a particular drug, as is often the case. Read more […]

Brain Impairment And Alcohol Abuse

Alcohol ranks as one of the most serious substances of abuse due to the prevalence of abuse in the general population and the severity of its toxic effects. It has been estimated that between 5 and 12 million individuals abuse alcohol, with a significantly greater proportion being male. The acute effects of alcohol intoxication are well known. Some of the effects of chronic alcohol abuse are also well known and have been extensively reviewed, particularly the dramatic effect of alcohol on memory in the case of Korsakoff ‘s syndrome. Less clear and still somewhat controversial are answers to the following questions: 1. What are the cognitive effects of chronic alcohol abuse in the absence of Korsakoff ‘s syndrome? 2. What, if any, are the direct toxic effects of alcohol on brain tissue? 3. Are there cognitive predictive factors for individuals at high risk for alcohol abuse? 4. What is known about the recovery of cognitive functions after abstinence from chronic alcohol abuse? As with all drugs of abuse, alcohol is initially sought out for its pleasurable effects which are mediated in the brain by its impact on the mesolimbic reward system. Recent evidence, however, points to alcohol’s impact on the Read more […]

Neuropsychological Findings in Chronic Alcoholism with Korsakoff s Amnesia

Considerable neuropsychological attention has been focused on the cognitive features of Korsakoff’s syndrome. Afflicted individuals first undergo an acute encephalopathic crisis called Wernicke’s encephalopathy which resolves into a persistent and severe amnesia referred to as Korsakoff’s amnesia. The characteristics of this amnesia include a severe anterograde loss of memory during which the afflicted individual is unable to learn new verbal or nonverbal information that is declarative and episodic in nature. Declarative memory refers to knowledge of facts or events that can be consciously stated or declared by the individual. Episodic memory, as noted earlier, refers to recall of facts or events that occurred at a specific time in a person’s life, such as recalling what one ate for breakfast in the morning. The anterograde amnesia in Korsakoff’s syndrome is often accompanied by normal or near normal intellectual functions and a milder retrograde amnesia. Retrograde amnesia refers to difficulty retrieving facts or events from long-term memory that occurred before the onset of the illness. It is usually more pronounced for events that occurred just prior to the onset of the illness, while remote events, such as childhood Read more […]

Neuropsychological Findings in Nonamnesic Chronic Alcoholism

More recently, neuropsychological interest has focused on documenting the chronic effects of alcoholism in the absence of Wernicke-Korsakoff syndrome. In 1971 Ryback proposed the continuity hypothesis, which posits that Korsakoff’s syndrome is the end product of a gradual decline associated with chronic alcoholism. In addition, chronic alcoholics without Korsakoff’s syndrome have often been used as control subjects in studies on Korsakoff patients without a full understanding of the nature of their specific cognitive deficits. Studies that have looked directly at the question of similarities or differences in cognitive functioning between Korsakoff amnesics and nonamnesic chronic alcoholics do not, in general, support the continuity hypothesis. In one study, Wilkinson and Carlen compared Korsakoff patients with non-Korsakoff alcoholics and found significant differences between the two groups on most subtests of the Wechsler Memory Scale, the digit symbol subtest of the Wechsler Adult Intelligence Scale (WAIS), and the memory score of the Halstead-Reitan Tactual Performance Test. Krabbendam and colleagues looked at neuropsychological data and magnetic resonance imaging (MRI) brain structure volumes in a group of Korsakoff Read more […]

Recovery of Function after Chronic Alcohol Abuse

The importance of abstinence for the recovery of functions in chronic alcohol abusers cannot be more strongly emphasized, given the severity of the risk for permanent brain damage associated with long-term, protracted abuse and given recent studies that show some recovery of neuropsychological functioning is possible in abstinent chronic alcohol abusers who have not suffered Korsakoff ‘s syndrome, cerebellar degeneration, or irreversibly damaging encephalopathic conditions. Rourke and Grant found that chronic male alcoholics who maintained interim abstinence for a period of two years following initial detoxification showed improvement on neuropsychological tests of abstracting ability compared with a group of chronic male alcoholics who resumed drinking during the two-year post-detoxification period, and compared with a control group of long-term abstinent alcoholics and a control group of nonalcoholics. The latter two groups were comparable in their neuropsychological performances on measures of abstracting ability, complex perceptual-motor integration, and simple motor skills. The group of relapsed chronic male alcoholics showed deterioration in their performance on the motor tests. In another study that looked Read more […]

Brain Impairment And Illicit Drug Abuse

Studies of General and Polydrug Abuse Our more recent understanding of how drug addiction occurs involves the interference of brain reward circuits, resulting in an increase in the desire to use. In particular, it is posited that the amygdala and subregions of the basal forebrain are involved in a mesolimbic dopamine system that activate mesolimbic dopamine function. Repeated use alters dopamine production, resulting in a dysregulation of the brain reward circuitry. The result is a biological addiction to the drug. With such brain involvement and alteration of the brain circuitry, alterations in neuropsychological functioning is likely. A preliminary report of neuropsychological functioning in polydrug abusers by Grant and colleagues noted a study in which 15 polydrug users were administered a comprehensive neuropsychological battery including neuropsychological tests from the Halstead-Reitan Neuropsychological Test Battery, as well as the Wechsler Adult Intelligence Scale and the Minnesota Multiphasic Personality Inventory (MMPI). The 15 polydrug users were compared to a group of 66 psychiatric inpatients. Although both groups demonstrated severe psychopafhology, as measured by the MMPI, the patterns of neuropsychological Read more […]

The Neuropsychological Consequences of Cocaine

Cocaine, a derivative of the coca plant, was first noted for its use among South American Indians sometime between 3000 and 1500 B.C.. Cocaine became popular for pharmacological use in medicine in the late 1800s since it offered both anesthetic and mood-altering properties. In the 1980s, estimated use of cocaine on at least one occasion affected more than 22 million Americans. With the introduction of “crack” in 1985, a resurgence of cocaine use was observed. By the mid-1990s, it was estimated that 1.5 million Americans used cocaine. The effects of chronic cocaine use include irritability, fatigue, depression, impotence, and loss of libido. Neurotoxic reactions resulting in cardiac arrhythmia, convulsions, and respiratory failure have also been noted. Cocaine has been documented for its powerful psychologically addictive qualities with a question as to the extent to which there is an actual physical addiction or associated withdrawal syndrome. The neuropsychological studies that have focused on cocaine use have not been as forthcoming as the studies that have focused on neuroimaging. Although neuropsychological impairment has been documented in cocaine abusers, studies have not been able to support differential diagnoses Read more […]

The Neuropsychological Consequences of Marijuana

Although the use of marijuana became especially popular during the 1960s, its use since then has appeared to decline significantly. THC, or tetrahydrocannabinol, is the psychoactive ingredient in marijuana that is now used for experimental medical use and for its anti-emetic and appetite-enhancing effects in cancer patients. As with cocaine, the neuropsychological research has been mixed regarding the effects of marijuana use on long-term cognitive functioning. An early study of long-term effects examined a group of ten individuals who smoked marijuana daily for an average of five years. The authors concluded that when compared to nonusers, minimal differences in cognitive functioning were observed with no support for any differences between groups on complex cognitive tasks. As with most substance-abuse research, the short-term effects of marijuana have received greater attention in the research literature. The allegation that marijuana in some way enhances creative or associational thinking was tested by Tinklenberg and colleagues. In this study, 16male subjects were tested while under the influence of marijuana. Contrary to myth and popular belief, the authors concluded that marijuana did not increase fluency, Read more […]

The Neuropsychological Consequences of LSD

Lysergic acid diethylamide (LSD-25) is a natural substance and hallucinogen that made its appearance in modern times during the mid-1900s. Its use peaked in the American culture in the 1950s and 1960s. LSD became most popular for its mind altering effects, which include visual distortion and hallucinations, a distorted sense of time, feelings of detachment, alterations in sensory perception, emotional lability, and mystical experiences. There has been a question as to whether LSD use results in organic brain damage. An early study by McGlothlin et al. examined sixteen subjects who had received LSD in either an experimental or psychotherapeutic setting. These subjects and controls, who were matched for sex, age, and education, were administered a number of spatial and visual tests including the Trail Making Test, which assesses the speed and accuracy of visual scanning and cognitive flexibility. Also, a measure of general intelligence, a verbal fluency test, and tests from the Halstead-Reitan Neuropsychological Test Battery were administered. Results revealed that only the category test, which assesses nonverbal reasoning and abstract problem solving, demonstrated a significant difference in performance between the two Read more […]