When Navy fighter pilot "Maverick" and his sidekick "Goose" declare "I feel the need  the need for speed!" in the box-office hit "Top Gun," they're speaking about the capabilities of their fast and furious F-14 Tomcat.

In the air war over Afghanistan, "the need for speed" may have taken on quite a different meaning.

"Speed" is the well-known nickname for amphetamines, the controversial and potentially harmful drug some American pilots are taking in order to enhance their performance. Despite the possibility of addiction and potential side effects that include hypertension and depression, such drugs are needed, military officials believe, in order to stay alert and focused  especially on long-range bombing missions. Such flights can mean nine hours or more alone in expensive, high-performance aircraft. Their lethal weapons are aimed at an elusive enemy that can be (and has been) confused with civilians or friendly troops.

According to military sources, the use of such drugs (commonly Dexedrine) is part of a cycle that includes the amphetamines to fight fatigue, and then sedatives to induce sleep between missions. Pilots call them "go pills" and "no-go pills." For most Air Force pilots in the Gulf War (and nearly all pilots in some squadrons), this was the pattern as well.

The drugs are legal, and pilots are not required to take them  although their careers may suffer if they refuse.

Amphetamines follow a pattern that goes back at least 40 years to the early days of the Vietnam War  further back if one counts strong military coffee as a stimulant. But they're also part of a new trend that foresees "performance enhancements" designed to produce "iron bodied and iron willed personnel," as outlined in one document of the US Special Operations Command, which oversees the elite special-operations troops that are part of all the military services.

Indeed, the ability to keep fighting for days at a time without normal periods of rest, to perform in ways that may seem almost superhuman (at least well beyond the level of most people in today's armed services), is seen by military officials as the key to success in future conflicts.

"The capability to resist the mental and physiological effects of sleep deprivation will fundamentally change current military concepts of 'operational tempo' and contemporary orders of battle for the military services," states a document from the Pentagon's Defense Advanced Research Projects Agency (DARPA). "In short, the capability to operate effectively, without sleep, is no less than a 21st Century revolution in military affairs that results in operational dominance across the whole range of potential U.S. military employments."

A 'radical approach'

What's called for, according to DARPA, is a "radical approach" to achieve "continuous assisted performance" for up to seven days. This would actually involve much more than the "linear, incremental and ... limited" approaches of stimulants like caffeine and amphetamines.

"Futurists say that if anything's going to happen in the way of leaps in technology, it'll be in the field of medicine," says retired Rear Adm. Stephen Baker, the Navy's former chief of operational testing and evaluation, who is now at the Center for Defense Information in Washington. "This 'better warrior through chemistry' field is being looked at very closely," says Admiral Baker, whose career includes more than 1,000 aircraft-carrier landings as a naval aviator. "It's part of the research going on that is very aggressive and wide open."

In a memo outlining technology objectives, the US Special Operations Command notes that the special-forces "operator" of the future can expect to rely on "ergogenic substances" (such as drugs used by some athletes) "to manage environmental and mentally induced stress and to enhance the strength and aerobic endurance of the operator."

The memo continues: "Other physiological enhancements might include ways to overcome sleep deprivation, ways to adjust the circadian rhythms to reduce jet lag, as well as ways to significantly reduce high altitude/under water acclimatization time by the use of blood doping or other methods."

Although the Air Force Surgeon General's office recently acknowledged that "prescribed drugs are sometimes made available to counter the effects of fatigue," it is not publicly known how widespread the practice is or whether special-operations forces on the ground in Afghanistan are taking such drugs.

But it is certainly widely talked about among combat veterans and military experts.

"Given the extent of recreational drug use within the military, and the use of performance-enhancing drugs among athletes, it is very easy to imagine that warriors would consider using any manner of drug they thought would increase their chance of returning home alive," says John Pike, a defense expert with GlobalSecurity.org in Alexandria, Va.

During the Gulf War, according to one military study, "pilots quickly learned the characteristics of the stimulant [Dexedrine] and used it efficiently." Pilots were issued the pills and took them if and when they felt the need.

Some people have defended that practice. "If you can't trust them with the medication, then you can't trust them with a $50 million airplane to try and kill someone," says one squadron commander whose unit had the fewest pilots but flew more hours and shot down more Iraqi MIGs than any other squadron.

But military officials, as well as medical experts, warn that the use of amphetamines can clearly have its bad side.

The flight surgeon's guide to "Performance Maintenance During Continuous Flight Operations" (written by the Naval Aerospace Medical Research Laboratory in Pensacola, Fla.) mentions such possible side effects as euphoria, depression, hypertension, and addiction. There's also the possibility of "idiosyncratic reactions" (amphetamines can be associated with feelings of aggression and paranoia) as well as getting hooked on the "cyclic use of a stimulant/sedative combination."

"The risk of drug accumulation from repetitive dosing warrants serious consideration," the guide notes. The "informed consent" form that military pilots must sign notes that "the US Food and Drug Administration has not approved the use of Dexedrine to manage fatigue."

Amnesia on the job?

It's not just the "go pills" that can cause problems in certain individuals. "No-go pills," used to induce sleep, can have dangerous side effects as well  including the possibility of what's called "anterograde amnesia ... amnesia of events during the time the medication has an effect."

"For the military aviator, this raises the possibility of taking the medication, going to a brief, taking off, and then not remembering what he was told to do," according to the lab's report.

But researchers say suchsymptoms "are primarily dose related and are not expected with 5-10 mgs of dextro-amphetamine (Dexedrine)"  the amounts given to pilots in the Gulf War and in Afghanistan.

For the most part, the issue of prescribed drug use by US pilots has gone unreported in the United States. But in England and Canada, it has been raised recently  especially in a possible connection with errant bombings.

In April, four Canadian soldiers were killed and another eight injured when an American F-16 pilot on a long-range mission, thinking he was under attack, dropped a 500-pound laser-guided bomb on an allied military exercise.

"The initial version of the Canadian incident portrayed the pilot as behaving with inexplicable aggression tinged with paranoia, and my first thought was that the poor guy had been eating too much speed," says Mr. Pike of GlobalSecurity.org. Officials are still investigating that accident, and the pilot has been questioned, among other things, about the possibility of drug use.

More recently, concerns have been raised about aggression and violence among soldiers returning from Afghanistan. In three of four cases in which men killed their wives, the accused husbands were in special-forces units based at Fort Bragg, N.C.

"It is quite obvious that someone needs to pose this question in the context of the business at Fort Bragg," says Pike. "This sort of hyper-aggressive behavior is just what one would associate with excessive use of such drugs or from withdrawal from using them."

As the US moves into an era in which national security is likely to mean wars fought from the air  using attack aircraft and small, specially trained units flown long distances to the battlefield  the issue of performance-enhancing drug use by US military personnel is likely to escalate. "The real story here is the ever-extending reach of air power," says Daniel Goure, a military specialist at the Lexington Institute in Arlington, Va. "We were flying F-15s out of Lakeheath [a Royal Air Force base] in the United Kingdom during Kosovo. Why? Because we had used up the available landing space everywhere else."

"As asymmetric threats such as ballistic missiles become more available to our adversaries, we are going to stand even farther back," adds Dr. Goure. "That means that this problem [i.e., the need to combat pilot fatigue] can only grow."