Performance Enhancing Drugs
Psychoactive substances have been used in combat for thousands of years. Alcohol has a long history of use on the battle-field, probably as a result of the euphoric feeling andloss of inhibition it can produce. In modern times, the most extensive, officially sanctioned use of drugs to enhance performance in combat has been the use of amphetamines by most armies, including the US Army, during World War II. These stimulants prevented fatigue and drowsiness, and improved concentration and memory. Amphetamines and caffeine have been the most studied performance enhancers in the military.
The high frequency of psychiatric casualties from battlefield stress seen in intense military operations suggests that a compound with antianxiety properties could, in theory, be of great benefit to soldiers. However, the optimal level of anxiety on the battlefield is a matter of some debate. Very low levels of anxiety in the face of danger are not desirable and could be fatal.
Post Traumatic Stress Disorder (PTSD) continues to affect numerous soldiers long after the battles of the war. PTSD played a pivotal role during and after every war America has fought. The constant regression between wars invariably leading to the cowardice label resulted in drastic individual treatment procedures in which self-medication prevailed. The percentage of veterans addicted to drugs, alcohol, and the use of tobacco following the Civil War, World War II, and the Vietnam War demonstrates the lengths Soldiers would go to ensure they did not receive a cowardice brand. Cecil Adams research identified that as many as 500,000 Civil War veterans developed an addiction to morphine. Moreover, 65 percent of World War II veterans adopted a lifelong cigarette habit. Heroin and marijuana were the drugs of choice during service in Vietnam, many veterans departed the country heavily addicted leading to assimilation problems upon their return to America.
By 1970 the Armed Forces continued to confront a deterioration of discipline. The unrest reflected the divisions within American society as a whole and their effects on the Services, which were engaged in a long and unpopular conflict. The prospect of redeployment actually weakened discipline, as servicemen found it difficult to maintain a sense of purpose in a war that was ending without decisive results. Rapid manpower turnover, a decline in training standards and personnel quality, and boredom as combat action diminished, added to the undermining of discipline and morale.
Drug abuse had reached crisis proportions. Drug abuse in Vietnam reflected the drug problem in American society, except drugs were cheaper and more easily available in Vietnam. The abundance of cheap, pure quality drugs, coupled with lax Vietnamese enforcement of its own narcotics control laws, made it easy for troops with drug habits to continue and facilitated experimentation by the uninitiated. Some 48 percent, or nearly half of the Marines, indicated a use of drugs at one time or another. In 1965 there had been 47 apprehensions; there were344 in 1966; 1,722 in the next year; 4,352 in 1968; and 8,446 in 1969. In 1970 the number was 11,058, despite rapidly dropping troop strength.
The use of compounds that are generally categorized as central nervous system (CNS) depressants to enhance or sustain performance would, at first glance, seem to be a paradox. However, such compounds have repeatedly been studied and used in military operations to promote sleep at desired times. By ensuring that soldiers sleep at appropriate times, subsequent mental performance will be preserved or improved.
Hypnotics or sedatives have also been used in attempts to speed reentrainment of circadian rhythms when military units cross multiple time zones or shift from day to night operations. Many drugs with hypnotic or sleep-inducing properties also have potent antianxiety effects. Such properties could, in theory, also be useful on the battlefield or in other high-intensity, stressful operations. However, the hypnotic-sedative effects of these compounds, including their adverse effects on mental performance, generally exclude their use as antianxiety agents in combat. Sedative-hypnotic drugs are used to treat anxiety and insomnia, and in some cases to prevent epileptic seizures. Although each drug has its preferred clinical usage, sedative-hypnotics are often capable of inducing various states of sedation, ranging from mild relief to deep sedation, depending on the dose. Thus, a drug commonly prescribed for its antianxiety effects may induce lethargy and sleep at higher doses. The decision regarding which drug to prescribe for a particular clinical condition is often based on its elimination half-life and side-effect profile.
A long-acting barbiturate such as phenobarbital is only slowly absorbed by fat tissue and muscle. Thus, the barbiturate circulates in the blood in concentrations sufficient to keep the individual sedated until it can be metabolized by the liver or excreted by the kidneys. Barbiturates are no longer generally used as hypnotics. They have been replacedby benzodiazepines and related compounds, and are a particularly poor choice in situations in which next-day performance is important.
Overall, the documented adverse effects of many of the benzodiazepines and related compounds, even those that are widely used with shorter half-lives (eg, triazolam [Halcion] and zolpidem [Ambien]), on performance the day after they are administered makes their use in combat or other intense operations a difficult medical/operational judgment. These compounds, like any drug, may sometimes have greater risks than benefits. The shortest-acting compounds (eg,zaleplon) probably have the lowest risk. Although the value of sleep cannot be overestimated, the adverse effects that these compounds have the next day could be potentially life-threatening in combat conditions.
CNS stimulants are drugs that increase alertness and improve mental performance. Several types of drugs are referred to as stimulants, and they vary widely in their structure and mechanism of action. The most important compounds with potential for use on the battlefield are amphetamines and drugs with similar actions. Newer stimulant-like compounds, which include modafinil and armodafinil, are now available for operational use; but, to date, only modafinil has been used operationally.
Another well-known stimulant-like compound, caffeine, is found in a variety of foods and is consumed on a daily basis by millions of people. The stimulant-like action of caffeine is from its effects on central adenosine receptors. In many countries, caffeine is the preeminent legal stimulant. Caffeine — a xanthine — is a behaviorally active, natural food constituent that is present in only a few foods.
Coffee has been a key element of soldier provisioning throughout the US Army’s existence. It has provided a morale boost in addition to the specific benefits of the caffeine component (eg, countermeasure to fatigue and depression). The beneficial effects of caffeine on specific types of performance in well-rested volunteers are well documented. In particular, it seems that tasks that require sustained vigilance are sensitive to the effects of caffeine in low and moderate doses. Sustained vigilance is a key element of a wide variety of essential military activities, such as performing sentry duty, monitoring surveillance equipment, and operating vehicles. Caffeine also has effects on self-reported mood states, most notably decreasing fatigue and increasing alertness.
Many individuals mistakenly believe that the primary stimulant in tea is theophylline, another xanthine compound. In fact, caffeine, not theophylline, is the principal, behaviorally active component found in tea. The drug theophylline — even though similar in structure and mechanism of action to caffeine — is not typically used for its stimulant-like actions, but rather to treat asthma. Theophylline also improves cognitive performance when administered in clinically effective doses.
Medical applications of amphetamines are primarily related to the treatment of attention deficit disorders in children and adults or as an alternative to methylphenidate in patients with narcolepsy. Although these agents have been used as appetite suppressants, this practice has been strongly discouraged because of the rapid development of tolerance and the high potential for abuse. Amphetamines arereadily absorbed after oral ingestion and are excreted by the kidney. Their half-lives can range from 7 to 30 hours. At therapeutic doses, the amphetamines produce increases in blood pressure, relaxation of bronchial muscle, increased plasma glucose and bloodflow to skeletal muscle with a concomitant decreasein blood flow to internal organs, and pupillary dilation. Typically, administration of an amphetamine will increase alertness, elevate mood, and improve concentration. However, adverse behavioral side effects can include increased irritability, restlessness, anxiety, and perhaps aggression. At higher doses,the drug effects are exaggerated. A slight tremor may be induced, respiration and motor activity increase, and insomnia occurs. Although amphetamines prevent fatigue, sleep cannot be postponed indefinitely, and rebound increases in sleep time will occur.
In World War II, amphetamines (eg, Benzedrine, metamphetamine) were extensively used by armies to combat fatigue, depression, and to enhance endurance performance. Some of the earliest evaluations were conducted by A.C.Ivy at the Harvard Fatigue Laboratory and involved caffeine comparisons with Benzedrine. This interest was stimulated by the use of methamphetamine by the Germans during the early years of the Blitzkrieg. The US Army continued to use amphetamines even after other countries like Germany and the United Kingdom were beginning to recognize problems associated with unrestricted use of the drugs. Both pill and inhaler forms were available.
One report concluded that approximately 60% of US Air Force Tactical Air Command aircrew occasionally used dextroamphetamine during operations in the Persian Gulf War. Dextroamphetamine was also used by the US Air Force during Operation Enduring Freedom in Afghanistan. Its use was widely publicized because several pilots were using it when they were involved in a friendly fire incident, and there was some concern that the pilots’ judgment may have been impaired by the drug.
Modafinil (Provigil [Cephalon, Inc, Frazer, Pa]) is a novel stimulant that, unlike the amphetamines, appears to have minimal peripheral side effects, has a low abuse potential, may not induce tolerance, and does not interfere with normal sleep. Its behavioral effects in healthy, sleep-deprived volunteers are of the same approximate magnitude as those of amphetamines, depending, of course, on dose. It can be concluded, based on evidence from a number of military and civilian laboratories, that modafinil has considerable potential as an operational performance enhancer because it appears to have the benefits of amphetamines without the adverse risks of abuse potential, increased blood pressure, and interference with sleep. In December 2003, modafinil was approved by the US Air Force for management of aircrew fatigue in dual-piloted bombers only after all other nonpharmacological countermeasures had been exhausted.
There are difficult socio-political issues associated with the officially sanctioned use of amphetamines in combat, and these would be greatly magnified if widespread use of the compound occurred in US military operations. Amphetamine, differently than caffeine and modafinil, increased risk-taking at the same time that prolonged wakefulness increasingly impaired judgment. Although some individuals will continue to debate the issue of the use of performance-enhancing drugs in military operations, it is apparent that such use will continue.
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