The development and control of attention probably results from changes at a variety of levels. On the one hand, studies suggest that the brain is becoming more mature and myelination more complete. On the other hand, children are becoming cognitively more sophisticated and able to employ limited sorts of conscious control over their attention.
In this lecture, first sketch the development of attention during the toddler years. You may wish to review material in the text, but flesh it out either with more detail from the studies cited or with additional studies. Characterize the typical child's attentional capacities during play, in interactions with adults, and while watching television. Discuss how such factors as fatigue, distractibility, and ability to understand what is happening influence attention. Consider the nature of the stimuli typical of these situations as well.
Next, outline the development of reaction time or other indices of basic information processing during this period (e.g., span of apprehension). You should be able to suggest a parallel between improvements in information processing efficiency on the one hand, and deployment, maintenance, and control of attention on the other.
Finally, present work that suggests that young children's attention can be improved if they are taught attentional strategies, such as talking to themselves in ways that direct their attention away from distracting stimuli. In development these points speculate about how efficient information processing may be necessary for adequate cognitive control.
Summarize your lecture by reviewing the various levels of information processing and cognitive control. You may wish to use a diagram or flow chart of some sort to organize these levels and suggest relationships between them. The result will be an organized presentation of information that relates basic brain development to enhanced cognitive functioning, as well as a scheme that will prove useful later in presentations about information processing approaches to cognition.
Should children be taught to draw? Or should they be allowed simply to draw however they wish, letting their motor, perceptual, and cognitive skills develop and enhance their drawing skills naturally?
Tackle these questions in a lecture that relates fine motor development during toddlerhood to children's drawing abilities. You may with to invite a day-care or kindergarten teacher to present information on typical experiences with drawing provided to young children, and have them comment on whether they are concerned with using training to enhance drawing abilities.
You may wish to open your (or your guest's) presentation to class discussion. Are there reasons why we might want to teach children to draw? Can drawing skills be trained? What is the nature of individual differences in drawing skill at these ages? Are these predictive of later skill? Were great painters talented scribblers as toddlers? You may find that this information is very interesting to students. Many suspect that drawing is something each of us wish we could do better if we only had the talent. But perhaps early training could enhance our subsequent artistic skills.
Children's drawings also provide an opportunity to discuss another observational approach to child development, the systematic study of things that children create. The work of Rhoda Kellogg is an excellent resource here. Get a copy of her Understanding Children's Art and prepare several overheads to illustrate children's drawings at several ages during early childhood. Begin a lecture/discussion by viewing these drawings in succession.
After broadly characterizing the developmental progressions apparent in the drawings, discuss how changes in the pictures might be analyzed or quantified. Review Kellogg's approach, but consider whether others are also appropriate. You should be able to show that the drawings can be assessed both quantitatively and qualitatively. For example, drawings will increase in number and accuracy of detail, but they will also increase in their organization and complexity. Patricia Greenfield has suggested that they, in fact, show changes in organization that parallel changes in language and cognitive development, exhibiting greater organization and hierarchical relationships between elements.
Conclude with a discussion of the value of drawings as measures of child development. Present in some detail one or two views, or sketch the range of interpretation given to drawings. You may wish to conclude this class with an assignment that requires students to get their own samples of drawings and subsequently to evaluate and interpret them using approaches such as Kellogg's.
Popular lore contends that biology looms large as a direct determinant of developmental behavior at the onset of adolescence. Hormones are said to create new sex drives, moods, and aggressive tendencies; some even suggest that girls become innately more interested in babies. Brain changes are said to lead directly to mental development. However, according to the 1984 Minnesota Symposium on Child Psychology, the issue is by no means so clear. Entrance into adolescence is also accompanied by radical changes in school experience, regard by adults, and individual children's expectations about how they ought to feel and what they ought to experience. Biological change is thoroughly confounded with social, cognitive, and personality change.
Discuss this problem in a lecture. Give reasons why interpreting behavioral changes as the direct result of biological changes is probably too simple, likely erroneous, and possibly even pernicious (e.g., do boys really have a powerful sex drive that must be released?). Outline Anne Peterson's schema for direct and indirect effects, and give real examples of both if you can find them. You may conclude that evidence for direct effects usually is confounded with other factors and that the evidence for indirect effects is more compelling. For example, the classic literature on early versus late maturers is a powerful hint that indirect effects are important. Another source is Laurence Steinberg's treatment of changes in parenting at puberty.
You may begin or conclude with the note that this is a classic issue in adolescence. Refer to the biological versus cognitive views of the period and the theoretical and practical consequences of taking either point of view.
Find a book written for young adolescents that is designed to teach them about their bodies. Make appropriate overheads of representative illustrations, and extract representative passages to show how the book teaches about the diverse physical and physiological changes of pubescence.
Next, compare the book's information with more formal presentations given in textbooks. Is the information accurate? Up-to-date? Does the book attempt to make the material suitable and palatable to young teens, or does it distort or misrepresent the information in any way?
Finally, analyze the approach taken by the book's authors to determine how well they apply what is known about cognitive, emotional, and personality development in their presentation. Speculate on the likely effect the book would have on its consumers according to your analysis. Would they benefit from it? Would their questions likely be answered? If necessary, make recommendations about how the book could be improved.
Some of the best research on adolescence is James Tanner's research on physical and physiological development during adolescence. Tanner's work has been the standard reference for better than 20 years. He performed meticulous, detailed descriptive studies that have provided standards for determining developmental age, typical growth rates and causes of atypical growth rates, and the precise nature of biological changes that occur throughout adolescence.
Use Tanner's work both as a model of excellent research and for the information it provides about adolescent physical and physiological development. His books contain a wealth of photographs, tables, and graphs that can be used to illustrate the uses of data as well as trends in growth and development. This information also illustrates the concept of stages of growth, qualitative versus quantitative change, and stable versus changing characteristics. As such, it can serve as an important reprise of these basic developmental concepts as you near the end of the course.
Of course, all bodily systems are becoming more complex and larger from birth on. Here are a small number of physical bodily changes that occur in the early years: Ossification is the process by which cartilage is turned into hard bone. At birth, the only ossified bones are in the face and cranium. During childhood, girls are ahead of boys, and blacks are ahead of whites in the ossification process.
Muscles grow at twice the pace of bone growth. The increased size and strength of the muscles allow toddlers to engage in better motor abilities and play activities. Infants have thin skin layers and limited ability to produce pigmentation. Therefore, infants are more susceptible to blistering, chafing, and sunburn than are older children and adults. In addition, sweat glands of infants are not yet fully functioning.
During the first year, the heart doubles in weight and shifts from an almost horizontal to a more vertical position. In the first months, walls of the left ventricle become thicker than the right because the left ventricle is more crucial in pumping blood to the rest of the body.
Weight of the lungs doubles from birth to six months and triples from birth to the first year. Salivary glands mature at about the third month, and at this time there is an increase in drooling. (Sources: Ashburn, S. S. 1986. Biophysical development of the toddler and the preschooler. In C. S. Schuster & S. S. Ashburn. The process of human development: A holistic life-span approach, 2nd ed. Boston: Little, Brown & Co.)
Synaptogenesis is the production of synaptic connections in the brain. The greatest numbers of synapses are produced in late prenatal and early postnatal periods. Density increases during the first two years of life, resulting in an overproduction of synapses. So, from 2 years to 7 years, there is a pruning of synaptic connections.
From 6 months to 7 years, children have more synapses than do adults. This high number may lead to a higher ability to learn object permanence and delay-response problems, and aid progress in walking and speaking.
Environmental factors also influence the amount of synaptogenesis. Rats in cages that allow exploration and enriched cognitive experiences end up with 25 percent more synapses per neuron in the upper visual cortex than do rats in conventional cages.
Greenenough suggests that initial overproduction of synapses is largely maturationally regulated, but how pruning of synapses takes place is largely dependent on experience. Normal experiences result in typical connections, but abnormal experiences result in atypical connections. (Sources: Siegler, R. S. 1989. Mechanisms of cognitive development. Annual Review of Psychology, 40, 353-379; Greenenough, W. T. 1985. Differential rearing effects on rat visual cortex synapses. I. Synaptic and neuronal density and synapses per neuron. Brain Research, 329, 195-203.)
Here are a few other facts about physical growth during the preschool years: By 4 years, preschoolers double their birth length. At 3 years, children's brains are three-fourths of their adult size; by 5 years, children's brains are about 90 percent of their adult size.
Preschoolers' skin becomes less soft as the water content of their skin decreases, and they develop fine hair on their legs and lower arms.
By their third birthday, salivary glands are adult-sized.
Changes in the brain allow preschoolers to have much better body temperature regulation than they did as infants and toddlers.
Preschoolers continue to have more ossification of their bones, but this process is not complete until early adulthood. Therefore, children in their early childhood years are more prone to bone, joint, and muscle injuries than are older children.
From birth until 5 years, children's hearts quadruple in weight.
During the preschool years, children's hair tends to become thicker, darker, and less curly.
Children in the play years have legs and feet whose appearance is affected by their early walking activities. Early walkers, for example, are more likely to have bowed legs and to be flat-footed. Flat footedness can be helped by allowing the young children to be barefoot most of the time. (Source: Schuster, C. S. & Ashburn, S. S. 1986. The process of human development: A holistic life-span approach, 2nd ed., Boston: Little Brown.)
The equipment and uniforms of medical personnel, and the formality of the offices of doctors and dentists, may scare small children. Parents should recognize their children's feelings as legitimate, and try to reassure their children. It is helpful to familiarize children with the typical procedure that doctors do. Presence of parents during appointments often reassure small children. It is also helpful to calmly inform small children about a half day before the appointment that they are visiting the doctor or dentist (Salk, 1983).
About 4,000,000 children stay overnight in a hospital each year. About 80 percent of pediatric hospitals and 49 percent of general hospitals have preadmission programs for children to help children learn about hospital procedures and to allay their fears. Parents can get a staff pediatric specialist at other hospitals to arrange an individualized pre-op hospital tour. Using hospital play, demonstrating typical procedures such as taking blood pressure, and being sensitive yet realistic in describing medical procedures helps children deal with hospital experiences (Richmond, 1989).
Towards the end of the play years, most children have come to believe that illness is caused by their behaviors or non-behaviors. They view sickness as a punishment for not obeying the rules (Elkind, 1981). Young children who are not feeling well need reassurance from their parents and other adults that they are not bad children. (Sources: Elkind, D. 1981. Recent research in cognitive and language development. In L. T. Benjamin, Jr. The G. Stanley Hall Lecture Series, Vol. 1. 65-88; Salk, L. 1983. What every child would like his parents to know, NY: Simon & Schuster. Richmond, S. 1989 (October). When your child goes to the hospital. Changing Times, 116.)
When biological aspects of the growth program are deficient, impairment of growth occurs. In juvenile hypothyroidism ("hypo-'' means "under,'' so hypothyroidism involves too little hormonal activity in the thyroid), for example, an 11-year-old may have the bone age of 6 years and the average height of a 7-year-old. This 4- to 5-year height deficit translates to more than nine inches. Treatment over a few years at this age can help to narrow the gap between this child with juvenile hypothyroidism and the average child (Fisher, 1988; Rivkees et al., 1988).
In pituitary dwarfs, the pituitary gland produces an inadequate amount of growth hormone. Growth hormone stimulates the liver to produce somatomedins, which in turn stimulate bone growth. Researchers have also found that adults produce more growth hormone when fasting (i.e., growth hormone is produced during fasting to mobilize fat while insulin is produced during feasting to increase fat storage), when under stress, or when running. Therefore, the main role of growth hormone may be to conserve muscle tissue at the expense of fat tissue.
While growth hormone is legitimately used to treat pituitary dwarfs, some parents get their normal-height children injections of growth hormone to make them taller, and hopefully more successful in sports and in getting prestigious jobs. After all, executives and bank presidents are usually taller than their employees, and even bishops average more height than priests.
Until recently, growth hormone was produced from the pituitaries of cadavers; 50,000 were processed each year to supply nearly 6,000 patients. However, since 1985 a genetically engineered version has been created, with the resulting cost now being closer to $10,000 a year for three injections a week. (Sources: Fisher, D. A. 1988. Catch-up growth in hypothyroidism. New England Journal of Medicine, March 10, 632-634; Rivkees, S. A., Bode, H. H., & Crawford, J. D. 1988. Long-term growth in juvenile acquired hypothyroidism: The failure to achieve normal adult stature. New England Journal of Medicine, 318, 599-602; Kolata, G. 1986. New growth industry in human growth hormone. Science, 234, 22-24.)
Asthma is a common respiratory illness that still goes underdiagnosed and undertreated. Many children (more boys than girls) who have asthma are diagnosed as having recurrent bronchitis or pneumonia. Of the 9.6 million asthmatic Americans, 3.2 million are children. About 10-12 percent of all children have asthma. In fact, about 80 percent of individuals who develop asthma exhibit some symptoms before the age of 5.
Asthma is airway obstruction from degranulation of mast cells in the lung's lining. The airways are affected by a variety of possible conditions, including an inherited genetic predisposition to asthma, viral infections, ingested allergens (e.g., milk, eggs), inhaled allergens (e.g., pollen, mold) pets, exercise, climatic changes (e.g., humidity), cigarette smoke, noxious fumes, and emotional stress. One study (Weitzman et al., 1990) that looked at the effects of passive smoking on asthma analyzed data from 4,331 children. Asthma was reported in 2.3 percent of children whose mothers did not smoke, 2.9 percent of children whose mothers smoked up to half a pack a day, and 4.8 percent of children whose mothers smoked at least half a pack a day.
Treatment during the acute phase is to create bronchodilation. Long-term treatment involves preventing or reducing the inflammatory process.
Many children with asthma (80-90 percent) wheeze, but wheezing can be an indicator of other heart or pulmonary problems. A minority of children have cough-variant asthma, in which a persistent cough instead of wheezing is the primary symptom.
Over 70 percent of asthmatic children have a mild case. In these cases, the asthma occurs seasonally or in response to a known stimulus. About 7 percent have severe asthma that requires frequent hospitalizations or emergency room visits.
Contrary to widely held beliefs: (1) Asthma does not typically mean frailty and no gym class. In fact, 11 percent of the athletes on U. S. Olympic teams have asthma. (2) Asthma is not outgrown, but about half of mildly asthmatic children experience a remission of symptoms during puberty. (3) Emotions are rarely the cause of asthma.
Typical symptom descriptions include episodes of: wheezing, cough, shortness of breath, chest pain, fatigue, loss of appetite, and upper respiratory tract infections. For children 5 and older, pulmonary function studies can be performed to document the degree of airway dysfunction or obstruction.
The first step in treatment is to stabilize the airways. Bronchodilation can be done using inhaled beta2-agonists. Theophyllines may be used because of their effect on respiratory muscle function. In some cases corticosteroids are used for a few days because of their direct anti-inflammatory properties.
Cromolyn sodium may be used in a maintenance program to stabilize the mast cell membrane and prevent its degranulation. Severe asthma may require large doses of bronchodilators and steroids.
One study of asthma (Weiss, 1990) compared hospital discharges and deaths due to asthma from 1982 through 1986. During this five-year period, there were nearly half a million hospitalizations annually for asthma. Hospitalizations were more common for those under 5 years and older than 65 years. Hospitalization rates for nonwhites were almost three times higher than for whites. During this time period, there were 18,114 deaths due to asthma, or an average annual mortality rate of 1.52 per 100,000 population. Mortality rates differed by age with 0.17 per 100,000 for children younger than 5 years to 6.71 per 100,000 for those at least 65 years old. Mortality rates for nonwhites were twice as high as for whites.
The researcher found that for persons aged 5 through 24 years, hospitalizations peaked in September through November and deaths peaked in June through August. For individuals older than 64 years, however, both hospitalizations and deaths were more common during December through February. (Sources: Hen, Jr., J. 1989 (Winter). Asthma: Dispelling the myths. PA Practice, 14-16; Weiss, K. B. 1990 (May 2). Seasonal trends in U. S. asthma hospitalizations and mortality. Journal of the American Medical Association, 263, 2323-2328; Weitzman, M. et al., 1990 (April). Maternal smoking and childhood asthma. Pediatrics, 85, 505-511.)
Epilepsy involves recurring seizures caused by abnormal, excessive, synchronous discharges of cerebral neurons. More than 6 percent of the population have experienced at least one epileptic seizure, but the overall prevalence of epilepsy in the United States is 1-2 percent. The highest incidence of epilepsy is in children under the age of 4; the incidence falls from 5 to 9 years, but climbs again from 10 to 20 years before declining throughout adulthood.
Epileptic seizures have three phases: prodrome (or aura), ictus (or seizure) and postictal state. The aura is a consciously remembered motor, sensory, visceral, or psychological aspect that warns of an imminent seizure, e. g., headache, unpleasant smells, dizziness, or a sense of déjà vu. Aspects of the prodrome and two other phases help to classify seizure disorders. There are three major categories: partial, generalized, and unclassified. Correct diagnosis of the type of seizure is the key to effective medical management of epilepsy.
Partial seizures are characterized by local onset, focused in a specific area of the body. Partial seizures are more common than generalized seizures. Simple partial seizures are brief (about 30 seconds). Characteristics may involve twitching to massive jerking of a limb, loss of sensation in a limb, sweating, pupillary dilation, déjà vu, dream states, fear, and anger. In this type of disorder, no loss of consciousness occurs.
Some partial seizures progress to a more generalized form; these seizures start with twitching and spread along the anatomic arrangement of the motor strip from face to arm to leg (called the "jacksonian march''). Sometimes this type of seizure progresses to a grand mal seizure and there is loss of consciousness. In the minority of cases, a transient paralysis (Todd's paralysis) that lasts up to hours may occur following the seizure activity.
One-fifth to one-fourth of seizures in children are complex partial seizures, which last up to eight minutes. These seizures involve hallucinations, cognitive and emotional changes, psychomotor automatisms (including blinking, mumbling, smacking the lips, picking at clothes), and impairment of consciousness. Some complex partial seizures progress to generalized seizures.
Generalized seizures are bilateral and symmetrical. The best-known kind of generalized seizure is the tonic-clonic or grand mal seizure, which is experienced by just over one-tenth of epileptics. These tonic-clonic seizures are characterized by sudden loss of consciousness preceded by an aura. The tonic phase involves body rigidity, an "epileptic cry,'' and the rolling up of the eyes; the clonic phase involves rapid jerking of the head and extremities followed by slower jerking, incontinence, and breathing through clenched teeth. The tonic-clonic seizure lasts about one to two minutes, typically followed by a postictal state of unarousable coma (up to five minutes), confusion, disorientation, and deep sleep (one to two hours). Grand mal seizures are associated with significant mortality rates and are treated as a medical emergency.
Absence seizures, also known as petit mal seizures, are characterized by abrupt onset and no aura. They usually last two to fifteen seconds, but can occur 100 times a day, or up to 30 times in one hour. During the absence seizures, the patient stares while eyelids flutter rhythmically. Recovery is immediate, although there is amnesia for the event. Absence seizures usually appear between the ages of 4 and 10 and become less frequent with age, often disappearing by age 20.
Atonic seizures and myoclonic seizures occur almost exclusively in children. Atonic seizures produce loss of body tone; myoclonic seizures produce violent contraction of the neck, trunk, and upper extremities. Falls associated with both of these types may cause serious injuries, and patients may wear helmets to prevent serious head injuries.
Infantile spasms are myoclonic-like seizures that usually begin around 4 to 6 months. They involve jackknife seizures that come in a series. The incidence of mental retardation in infants with this disorder approaches 85 percent.
Epilepsy is a condition with many possible etiologies, such as congenital or developmental birth defects, anoxia or other birth injury, genetic metabolic defects, central nervous system infections, tumors, abscesses, head injury, toxins, and degenerative disease. (Source: Stajich, J. M. 1989 (November). Common neurological disorders. Part I: Vascular syndromes and epilepsy. Physician Assistant, 13-30.)
Have your class discuss what they know about anabolic steroids, whether they know of users (if not a personal friend, the Canadian track star Ben Johnson might be mentioned), and what they would do to reduce steroid usage among adolescents. Somewhere between 6 and 15 percent of high school boys have tried steroids or are current users. Anabolic steroid use among college athletes increased from 4 percent in 1985 to 5 percent in 1989. Would you want schools to do random drug testing of athletes (or all students) to reduce steroid use?
The first healthy persons to use anabolic steroids were not athletes, but Hitler's SS troops in World War II, to increase their aggressiveness. In 1954, a medical report mentioned that Russian athletes were using the steroids and by 1956 American athletes had methandrostenolone (Dianabol) available.
Two major patterns of taking anabolic steroids emerge among athletes. One technique is the "stacking principle,'' or the simultaneous use of different anabolic steroid preparations to saturate many receptor sites. The second technique is a cycling method, which involves using different steroids over a six- to twelve-week period. Some do this style in a belief that it minimizes negative effects. It also means that specific steroids can be scheduled to meet different needs for competition.
Athletes use anabolic steroids to increase lean body mass, strength, and aggressiveness, and to reduce recovery time between workouts. Side effects during steroid use can include: increased muscle mass, dramatic mood swings, sleep disturbance, altered libido, male pattern baldness, acne, and facial hair in both female and male users. Side effects for males include gynecomastia (breast development), impotence, and lowered sperm count. Side effects for females include masculinization, cliteromegaly (enlarged clitoris), and hirsutism (male pattern of body hair). Adolescents who use anabolic steroids can experience precocious puberty. More serious effects (which may be irreversible) for both males and females include: impeded growth, early heart attack or stroke, liver failure or liver cancer, psychological addiction.
Abnormal aggression, mood swings, and psychiatric dysfunctions are also associated with anabolic steroid use. In a study of 41 football players and body builders who had used steroids, nine had the DSM-IIIR criteria for full affective syndrome and five had psychotic symptoms during the steroid usage. In a study of 100 health club athletes who used steroids, 90 percent reported episodes of aggressive and violent behavior.
In 1984, a report came out that 59 Soviet Olympic competitors and users of steroids had died. The study was poorly monitored, and in fact, some now believe that the report was a politically-inspired hoax rather than a valid scientific report. It may be that steroids cause medical complications, but not as many severe and fatal ones as assumed just a few years ago. (Sources: Sobel, D. 1989 (October). Health watch: Teens and steroids. Ladies Home Journal, 110; Windsor, R. E. 1988 (September 15). Anabolic steroid use by athletes: How serious are the health hazards? Postgraduate Medicine, 84, 37-49.)
Acne affects mostly teenagers, but it can occur in young children and in adults. Most adults with acne had acne in adolescence, but some do develop acne in their twenties and thirties.
Acne has several etiologies, including heredity and hormones. These factors trigger excessive oil production, causing oil ducts to become plugged, forming pimples and blackheads. Bacteria in the oil ducts aggravates acne.
Today, many medications are available to reduce the clogging of oil ducts and reduce the bacteria in the ducts. Benzoyl peroxide is available over-the-counter or in stronger forms by prescription. This medicine is applied on the skin and helps to reduce bacterial levels.
A prescription is needed for Retin-A, which will split apart skin cells that clump together in an oil duct. If using this medication, one must avoid sun exposure, use sunscreens, and wash only with mild soaps.
Certain antibiotics can be prescribed to reduce the levels of bacteria in the skin.
Hormone therapy can be used, because fluctuating levels of ovarian hormones can cause acne flare-ups, especially premenstrually. Prescribing an estrogen-containing oral contraceptive may work here. When women develop acne for the first time in their twenties or later, the problem is more likely to be due to increases in androgen. Control of this type of acne may involve oral contraceptives, cortisone-related medications, or androgen-blockers.
The most potent prescription medication for treating acne is accutane, which reduces oil production, plugging of the oil ducts, and bacteria in the skin. However, this drug is known to cause birth defects so it must be avoided with anyone who is pregnant or might become pregnant soon. When accutane is used, it is the sole treatment; the other possible solutions can be used in combination.
Assessment should also be done as to whether or not the person with acne is using any medications or cosmetics that can aggravate the situation. Oral contraceptives containing progestins and some anticonvulsant drugs, for example, may make acne worse. Cosmetics should be labeled "noncomedogenic,'' which means that clinical tests have shown them to not contribute to skin problems. (Source: Sobel, D. 1990 (March). Acne treatments that could work for you. Good Housekeeping, 241.)
Although some adolescents are quite physically fit and plan their lives around exercise, good nutrition, and other good health habits, many adolescents are physically unfit. Some teenagers have bad health because of unhealthy choices—using drugs, smoking cigarettes, eating junk foods, leading inactive lives—but others are unfit largely due to the nonadoption of good health habits.
Between 1966 and 1986, there was a 39 percent increase in obesity among twelve- to seventeen-year-olds. Obesity tends to be resistant to change. About 70 percent of obese adolescents become obese adults. Only a minority of teenagers are obese because of binge-eating patterns; most obese teenagers overeat by a few too many calories consistently while underexercising (Science, 1986).
Heavy television viewing by adolescents is associated with obesity and other physical problems. For every hour of television viewing, the prevalence of obesity among teens goes up 2 percent (Dietz & Gortmaker, 1985). Television viewing encourages snacking and paying attention to food ads that push sugary or fatty foods while discouraging healthful exercise (Science, 1986).
Adolescents also model other adult behaviors that build unhealthy lifestyles. Many teenagers, for example, learn Type A behaviors of speed and impatience and hard-driving competitiveness from adult models. Within families, sons are especially likely to pick up this rapid, push style from their fathers (Weidner et al., 1988).
Schools can become part of the solution by providing more consistent and practical physical fitness education for all students. Currently among fourteen-year-olds, only 25 percent can do ten pull-ups and only 25 percent of all girls can do one pull-up. Twenty-five percent of all adolescent boys and 50 percent of all girls need longer than a half-hour to walk two miles (President's Council on Physical Fitness and Sports, 1987).
The best solution, however, is for adolescents and their parents to choose better health habits. For example, teenagers can limit their television viewing, eating fewer calorie-rich snacks, and cut down on alcohol, cigarettes, and other drugs. Teenagers can engage in regular physical exercise (such as walking, aerobics, bicycling, or swimming), eat nutritious foods regularly, switch to snacks such as raw vegetables, and get enough sleep and relaxation. (Sources: President's Council on Physical Fitness and Sports. 1987. 1985 School Population Fitness Survey. Washington, D.C.; Science. 1986. Obese children: A growing problem. Science, 232, 20-21; Weidner, G., Sexton, G., Matarazzo, J. D., Perieira, C., & Friend, R. 1988. Type A behavior in children, adolescents, and their parents. Developmental Psychology, 24, 118-121.)
Cannabis sativa or marijuana has been cultivated for at least 5,000 years, but its use has never been as prevalent as in the last few decades. A 1985 National Institute on Drug Abuse survey reported that 62 million Americans had tried marijuana with 29 million using within the last year. In 1986, 5.1 million high school students (12 to 17 years old) had used marijuana (4.3 million in past year; 2.7 million in past month). In 1987, 16 percent of employed persons between 20 and 40 years old used marijuana within a month of when the survey was done. A 1988 study found detectable blood levels of marijuana in one-third of 1,023 patients treated for shock/trauma following accidents in Baltimore. In other words, marijuana is the most frequently used illicit drug in the United States.
While many persons think of marijuana as a harmless mind-altering substance, cannabis contains more than 400 chemicals, including 61 cannabinoids, 11 steroids, 20 nitrogenous compounds, 50 hydrocarbons, 103 terpenes, and benzopyrene. The effects on the body of most of these components is still unknown.
The primary psychoactive agent is THC, or tetrahydrocannabinol. In the 1970s THC content of marijuana ranged from 1 to 3 percent of the marijuana, but in the 1980s, more potent varieties of marijuana raised the THC content to between 5 and 15 percent. Tetrahydrocannabinol is fat soluble and it binds tightly to proteins in the blood. Therefore, THC is quickly taken up by tissues that are well supplied with blood: the liver, spleen, lungs, kidneys, testes, and ovaries. THC reaches the brain within 14 seconds of being smoked. The half-life of THC is about 56 hours in first-time users and 28 hours in long-term users. THC may remain in body tissues for 30 days or more; in fact, cannabinoids may be found in the urine for up to 30 days after marijuana use.
Most marijuana users report pleasant subjective effects of euphoria, joy, and light-heartedness. Users may believe that they are more creative, philosophical, innovative, and carefree. However, some users report unpleasant subjective effects such as anxiety, jitters, paranoia, hallucinations, and loss of energy and will.
The greater potency of marijuana means that more users may experience toxicity, tolerance, and physical dependence. For those users who are physically dependent, withdrawal symptoms may occur within several hours to several days after last use. Withdrawal symptoms may include chills/shakes, restlessness, confusion, fearfulness, malaise, cannabis craving, sweating, insomnia, nausea, irritability, attention deficits, increased blood pressure, increased respiration, sleep disturbances, and vomiting.
Medical consequences of high doses or long-term use of marijuana mostly affect the pulmonary system, the central nervous system, and the reproductive organs. Just a few of the medical complications of cannabis use are: tachycardia, laryngitis, bronchitis, tremors, decreased REM sleep, panic attacks, paranoias, memory impairment, lower sperm count, altered menstrual cycles, and fetal organ malformation and growth retardation. Perception of distance and time are impaired in a marijuana-intoxicated state, contributing to motor vehicle accidents. Marijuana makes it more difficult to learn new information. (Source: Bartholomew, S. 1990 (January). Marijuana abuse: Clinical implications. Physician Assistant, 45-52.)
Cocaine bought on "the streets'' has typically been "cut'' (mixed) with other substances four to eight times. "Cuts'' include mannitol, lactose, sucrose, caffeine, phenylpropanolamine, ephedrine, amphetamine, procaine, lidocaine, and benzocaine. These "cuts'' add volume and therefore profits to the dealers, but they also add medical risks to the ones inherent in the cocaine itself. Besides health and legal risks, cocaine creates financial problems. The street value of cocaine is more than six times the price of gold (National Institute on Drug Abuse, 1986).
Since smoking cocaine gained popularity, the incidence of myocardial ischemia, hypertensive episodes, and angina have climbed as complications of intravenous, freebased, and intranasal cocaine use. Cardiovascular manifestations are characterized by tachycardia and hypertension (Buchanan, 1989).
In the 1980s, the number of cocaine-related strokes climbed especially among adults in their twenties. Cocaine is now considered one of the leading causes of stroke in young people. Cocaine-caused strokes involved more intracerebral or subarachnoid hemorrhages (78 percent) than cerebral infarctions (22 percent), unlike other caused strokes (Emergency Medicine, 1990). A headache or any focal neurological deficit following cocaine use could be a sign of intracranial hemorrhage (Buchanan, 1989).
Seizures are more common after intravenous or freebased administration of cocaine than from intranasal use. The seizures probably result from the cocaine's blockage of the reuptake of norepinephrine and dopamine in the cerebral cortex. Mostly cocaine-induced seizures are transient (Buchanan, 1989).
Hyperthermia, caused by increased muscle activity, seizures, and vasoconstriction-induced impaired heat dissipation, plays a significant role in fatal cocaine intoxication. Cocaine may also directly affect hypothalamic thermoregulatory centers. Hyperthermia can lead to acute renal failure.
Psychological effects of cocaine intoxication are many. The user usually experiences increased feelings of power, special entitlement, and of being "in control.'' These feelings develop because cocaine acts on the pleasure center in the brain. However, the effect is temporary, because the presence of cocaine depletes the production of dopamine in the brain so that when cocaine is not present the user "comes down.'' Following cocaine binges, users often become significantly agitated and depressed, and suicide attempts are common. Personality changes associated with long-term cocaine use include exaggerated interest in detail, hypersensitivity to peripheral sensory cues, heightened anxiety, and paranoid thinking (Jorgensen et al., 1989). (Sources: National Institute on Drug Abuse. 1986. Cocaine use in America. Prevention Networks, April, DHHS Publication No. (ADM) 86-1433. Washington, DC: U. S. Department of Health and Human Services; Lerner, M. A. 1989 (Nov. 27). The fire of `ice.' Newsweek, 37-40. When coke leads to stroke. 1990 (April 15). Emergency Medicine, 35-38; Buchanan, J. F. 1989 (November). Cocaine intoxication: Presentation and management of medical complications. Physician Assistant, 187-193; Jorgensen, G. Q., White, Jr., G. L., & Woolley, D. E. 1989 (November). Psychological implications of cocaine dependence. Physician Assistant, 88; Farrar, H. C. & Kearns, G. L. 1989 (Nov.). Cocaine: Clinical pharmacology and toxicology. Journal of Pediatrics, 115, 665-675.)
Progeria refers to medical conditions in which there is premature or accelerated aging. Two examples of progeria are the Hutchinson-Gilford syndrome and Werner's syndrome.
With the Hutchinson-Gilford syndrome, patients who are ten years old may display the physical signs associated with persons older than 70. Sufferers look old and wizened, are bald, are dwarfs, and have generalized atherosclerosis. These patients usually die of coronary artery disease before the age of 20 years. The syndrome affects both males and females and individuals of various races and intelligences. The Hutchinson-Gilford syndrome is believed to be caused by an autosomal recessive trait.
About one in 1,000,000 babies is born with Werner's syndrome. About 200 individuals with this disease are living in the United States. With persons with Werner's syndrome, advanced aging occurs during their twenties, and if they survive into their forties they are biologically very old (average life expectancy of Werner's patients is 47). These patients are short, have thin limbs, a beak-shaped nose, receding chin, and juvenile cataracts. Sexual maturity is delayed.
They are predisposed to diabetes, osteoporosis, atherosclerosis, and calcified blood vessels.
An average person's cells would divide 50 times in a lab dish, but Werner's syndrome individuals' cells would divide only 10 to 20 times in this condition. Researcher Sam Goldstein found that 40 or 50 genes are contributing to this pattern, including some genes that are unique to Werner's syndrome. However, patients with Hutchinson-Gilford syndrome do not exhibit a decrease in the number of cell doublings.
These individuals are susceptible to cancer, heart disease, and osteoporosis. (Sources: Begley, S., Hager, M., & Murr, A. 1990 (March 5). The search for the fountain of youth. Newsweek, 44-48; Brown, W. T. 1987. Progeroid syndromes. In G. L. Maddox (Ed.). The encyclopedia of aging. New York: Springer; Cohen, G. D. 1988. The brain in human aging, New York: Springer.)