Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD), formerly known as attention deficit disorder (ADD), is the most common psychiatric disorder in children, affecting 3% to 10% of school-age children. Boys are affected from two to nine times more often than girls, although the disorder may be underdiagnosed in girls. Primary symptoms of ADHD are a developmentally inappropriate ability to maintain attention span and/or the presence of hyperactivity and impulsivity. The disorder may involve predominantly attention deficit, predominantly hyperactivity or impulsivity, or a combination of both. It usually begins before 7 years of age, sometimes earlier than 4 years of age. It can officially be diagnosed when symptoms last at least 6 months and occur in at least two different settings (e.g., home and school), according to the Diagnostic and Statistical Manual of Mental Disorders. Many children outgrow ADHD, but adult ADHD is also common. Drug therapy for both childhood and adult ADHD is essentially the same. There is some social controversy regarding possible overdiagnosis of, and overmedication for this disorder. Studies in twins indicate a degree of genetic predisposition and familial heritability. The disorder is commonly associated with other forms of mental illness, including depression, bipolar disorder, anxiety, and learning difficulties.

Narcolepsy

Narcolepsy is an incurable neurologic condition in which patients unexpectedly fall asleep in the middle of normal daily activities. These “sleep attacks” are reported to cause car accidents or near-misses in 70% or more of patients. Another major symptom of the disease is dysfunctional rapid eye movement sleep (see Chapter 12). Cataplexy is an associated symptom in at least 70% of narcolepsy cases. It involves sudden acute skeletal muscle weakness. The condition is often associated with strong emotions (e.g., joy, anger), and commonly the knees buckle and the individual falls to the floor while still awake. Men and women are equally affected, with approximately 100,000 cases in the United States. Some genetic markers have been identified. Roughly half of patients with narcolepsy experience migraine headaches as well.

Obesity

According to the National Institutes of Health and the Centers for Disease Control and Prevention, approximately 30% of Americans are obese and nearly two thirds (64.5%) are overweight. This translates into more than 72 million obese adults, with a higher incidence of obesity among women and minorities. Obesity was formerly defined as being 20% or more above one’s ideal body weight based on population statistics for height, body frame, and gender. More recent data are based on a measurement known as the body mass index (BMI), defined as weight in kilograms divided by height in meters squared (i.e., BMI = weight [kg] ÷ [height (m)]²). Overweight is now defined as a BMI of 25 to 29.9, whereas obesity is now defined as a BMI of 30 or higher. At any given time, one third of women and one quarter of men are trying to lose weight. Moreover, the incidence of obesity in young people 6 to 19 years of age has more than tripled since 1980. The pathophysiology of obesity is not fully understood, but calorie excess, disordered metabolism, and other factors are hypothesized. Obesity increases the risk for hypertension, dyslipidemia, coronary artery disease, stroke, type 2 diabetes mellitus, gallbladder disease, gout, osteoarthritis, sleep apnea, and certain types of cancer, including breast and colon cancer. An estimated 80% of diabetes risk in the United States can be attributed to excess weight. Some 112,000 deaths each year are linked to obesity. The related health care costs alone are currently estimated at more than $140 billion. Yet many people who attempt weight loss do so for cosmetic reasons rather than health reasons. Obese people are often stigmatized, at times even by the health care professionals treating them.

Migraine

A migraine is a common type of recurring headache, usually lasting from 4 to 72 hours. Typical features include a pulsatile quality with pain that worsens with each pulse. The pain is most commonly unilateral but may occur on both sides of the head. Associated symptoms include nausea, vomiting, photophobia (avoidance of light), and phonophobia (avoidance of sounds). In addition, some migraines are accompanied by an aura, which is a predictive set of altered visual or other senses (formerly termed classic migraine). However, the majority of migraines are without an aura (formerly termed common migraine). Migraines affect about 30 million people in the United States, with a reported incidence in females roughly three times that in males. Migraine headaches have been classified by the World Health Organization as one of the 19 most disabling diseases worldwide, with approximately 64 to 150 million workdays lost annually. Migraines commonly begin after 10 years of age and peak between the mid-twenties and early forties. They often fade after 50 years of age. Familial inheritance of migraine is well recognized. Precipitating factors include stress, hypoglycemia, menses, endogenous estrogen (including oral contraceptives), exercise, and intake of alcohol, caffeine, cocaine, nitroglycerin, aspartame, and the food additive monosodium glutamate (MSG). Over 50% of patients with narcolepsy report nocturnal migraines. Historically, there have been several theories regarding the cause of migraines, including the “vascular hypothesis” and the “neurovascular hypothesis.” Most recent evidence points to decreased serotonin levels. Thus, the majority of current investigations involve drugs that can increase the serotonin levels.

Analeptic-Responsive Respiratory Depression Syndromes

Neonatal apnea, or periodic cessation of breathing in newborn babies, is a common condition seen in neonatal intensive care units. It occurs in about 25% of premature infants whose pulmonary and CNS structures, including the medullary centers that control breathing, have not completed their gestational development because of preterm birth. Infants undergoing prolonged mechanical ventilation, especially at high pressures, often develop a chronic lung disease known as bronchopulmonary dysplasia, for which caffeine can be helpful. Postanesthetic respiratory depression occurs when a patient’s spontaneous respiratory drive does not resume adequately and in a timely manner after general anesthesia. Respiratory depression may also be secondary to abuse of some drugs. Hypercapnia, or elevated blood levels of carbon dioxide, is often associated with later stages of chronic obstructive pulmonary disease (COPD). Analeptic drugs such as theophylline, aminophylline, caffeine, and doxapram may be used to treat one or more of these conditions. Analeptic drugs are now used much less frequently than they were in the earlier days of general anesthesia. This is because of advances in intensive respiratory care, including mechanical ventilation and improved anesthetic techniques, as well as the availability of newer medications with less toxicity.

Pharmacology Overview

Drug Profiles