LSD, ecstasy (MDMA) and other psychedelics are powerful, mind-altering drugs that, as described by former Washington Post Magazine editor Tom Shroder, “intrinsically [challenge] the rationalist, materialist underpinnings of Western culture.” For most of a century, our society has struggled to come to grips with these “profoundly threatening drugs,” largely without success. They’ve all been made illegal. For decades, the Food and Drug Administration and the Drug Enforcement Administration have strictly banned scientific investigations into their potential benefits — which is unfortunate, since these psychoactive drugs also seem able to do incredible good, particularly in the treatment of post-traumatic stress disorder (PTSD).

As Shroder writes, “PTSD is usually triggered by combat, rape, childhood abuse, a serious accident, or a natural disaster.” Every year, as many as 5 million Americans suffer from its effects. Frequent consequences include depression, drug and alcohol abuse, and a host of associated health problems. In “both humanitarian and economic terms,” the costs are staggering.

And PTSD stubbornly resists treatment. Anti-depressant and ­anti-anxiety medications only ease symptoms. Traditional talk-therapy can take years to process root causes, and it isn’t reliably successful. Exotic psychoactive drugs such as LSD and MDMA seem to bring powerful healing energies to bear on the underlying issues. But despite a growing mountain of evidence supporting the therapeutic benefits delivered by these drugs, government authorities have blocked scientific and therapeutic explorations of their potential.

Fortunately, the government’s prohibitions may be loosening, thanks to a cadre of psychedelic advocates who have steadfastly refused to surrender to the taboos. The story of those people and their efforts to win scientific and therapeutic approval for psychedelic drugs is the central thrust of Shroder’s strangely wonderful new book, “Acid Test.”

To tell this fascinating tale, Shroder deviates wildly from strict chronology, which creates some confusion but, once you surrender to his process, somehow makes perfect sense — and mirrors the effects of the drugs he writes about. With liberal doses of psychedelic history and science interspersed among scenes as bizarrely diverse as intense therapy sessions, hard combat in Iraq, frustrating government hearings and drug explorations supervised by a South American shaman, Shroder develops three principal characters: Rick Doblin, a psychedelic-therapy advocate who, in college in the early 1970s, came to believe that “psychedelics, used with care and expertise, could do people and the world a lot of good” ; Michael Mithoefer, an ER doctor turned psychiatrist convinced of the healing power of psychedelic drugs; and Nicholas Blackston, a Marine combat veteran whose life was being ruined by PTSD.

”Acid Test: LSD, Ecstasy, and the Power to Heal” by Tom Shroder. (Blue Rider)

Having begun his career practicing emergency-room medicine, Mithoefer came to feel that he was often “catching the tail end of psychiatric problems” — heart attacks, stabbings and drug overdoses that were caused by “psychological problems coming to an end result.” Inspired to study psychiatry and attack fundamental causes, he returned to medical school and became a board-certified psychiatrist. Revolting against the tendency of modern psychiatry to drug away symptoms and institutionalize severe patients, Mithoefer sought better solutions. That search connected him with the healing potential of psychedelic drugs — and with Doblin, who’d devoted decades to accomplishing what seemed impossible: getting the government to approve the scientific and therapeutic use of psychedelic drugs. At the end of a multi-year struggle with intransigent bureaucracies, they finally received approval to conduct a preliminary investigation into whether MDMA helped resolve the psychic pain of PTSD-afflicted patients. Ex-Marine machine-gunner Blackston was one of the subjects selected.

In Iraq, Blackston survived terrible experiences. For a capstone horror, an insurgent bomb blew up his vehicle. Wounded by shrapnel, he helped his squad survive the subsequent ambush. A close friend bled to death in the chaos. After he returned home, PTSD began eating away at Blackston’s life. He suffered hallucinations, nightmares and constant anxiety. For trivial provocations, he leveled wild outbursts of rage at his undeserving fiancee and mother. He tried a variety of traditional therapies. None brought him any meaningful relief. With no end in sight, he contemplated suicide.

Fortunately, Blackston was chosen for Doblin and Mitheofer’s MDMA study. “Acid Test” reaches its positively thrilling climax in his intense ecstasy-assisted therapy sessions, administered by Mithoefer and his wife. In a safe, aesthetically pleasing environment, under the close supervision of qualified therapists, MDMA seems to “simply dissolve problems,” offering a shortcut to the “profound peace, total acceptance . . . [and] transcendent normality [that is] the wished-for endpoint of all therapy.” MDMA “helped [one] to trust in the process of opening up and to see that, even with difficult things, feeling them and integrating them” was the path to healing. Reading about the relief Blackston experienced practically brings tears to the eyes.

“Acid Test” makes a convincing case that such therapies ought to be prescribable by all practicing psychiatrists. With an average of 22 veterans a day committing suicide and the Department of Veterans Affairs on the hook for more than $1 trillion in PTSD-related expenses due to the wars in Iraq and Afghanistan, it’s hard to imagine how our society can afford to ignore the powerful healing potential contained in such profoundly psychoactive drugs as LSD and MDMA. Even more compelling is the moral debt we owe the PTSD-afflicted men and women who volunteered to fight our terrible wars.

Gregory Crouch , a graduate of West Point and a former infantry officer, is the author of “China’s Wings: War, Romance, Intrigue and Adventure in the Middle Kingdom During the Golden Age of Flight” and “Enduring Patagonia.”

Read an excerpt of “Acid Test” in The Washington Post Magazine.

ACID TEST

LSD, Ecstasy and the Power to Heal

By Tom Shroder

Blue Rider. 426 pp. $27.95