The script, written also by Michael Chricton, was based on the best-selling novel by Robin Cook, author of many successful medical thrillers. The movie protagonist is Doctor Susan Wheeler (played by Genevieve Bujold), young doctor in big Boston hospital. During her practice, she begins noticing a strange pattern of young and healthy patients falling into unexplained coma during the routine surgeries. She begins to investigate, although everyone, including her boyfriend and colleague Doctor Marc Bellows (played by Michael Douglas), doesn't believe her claims about all those cases being connected. Actually, the cause of that phenomenon becomes even more sinister after Doctor Wheeler survives an attempt on her life. Finally motivated to push through the bitter end, she begins to reveal the shocking truth.

COMA is just another example for all those film critics of today who consider 1970s to be the Golden Age of world cinema. That time period was very fruitful for many movie directors who had made many great films, only to deliver disappointments in the latter decades. Michael Chricton, acclaimed novelist, screenwriter and director was one of them, reaching the peak of his film career in 1970s. Many, including the author of this review, would claim that COMA happens to be his best film. One of the reason for that is Crichton's medical background that provided him an opportunity to create realistic settings and characters (same as with his hit TV-show ER two decades later). As a result, COMA is a film with very plausible plot and convincing characters. And the realism worked very well in order to create extremely scary atmosphere - the hospital, institution where the people are supposed to be safer than in all other places, is suddenly turned into place of unimaginable horrors. The movie is even more scarier than cult horrors that used to be very popular in those days; few people could imagine themselves being attacked by sharks or stalked by axe murderers and supernatural demons, but almost everyone could expect himself to end in hospital, helpless and totally at the mercy of people in white coats. Scariness also sprang from the widespread feeling of post-Watergate paranoia, when every segment of the establishment, including even the medical profession, caused suspicion about its good intentions or scruples.

Crichton's direction in this film is almost flawless. He presents the scenes of Doctor Wheeler's boring and totally unexciting domestic and professional every day life, shot in almost quasi-documentary fashion, and quickly replaces them with the breath-taking scenes of suspense. Doctor Wheeler's battle with the assassin in the dark corridors and autopsy room is one of those scenes that leave strong impact on the viewers. And the truth, being finally revealed in the Jefferson Institute, is one of the most memorable and frightening images in the history of cinema. The movie was deliberately left without original musical score for most of its part, except in the suspense scenes, when always reliable Jerry Goldsmith provides needed audio stimuli for suspense and horror.

Acting talent in this film is excellent. Genevieve Bujold was very well cast as a heroine of this film. She portrays Doctor Wheeler as a liberated, professional woman of 1970s, strong and stubborn, and yet vulnerable because of her physical limitations. In many ways she resembles Sigourney Weaver as Ripley in ALIEN, another feminist action hero faced with unspeakable horrors. The other actors mostly fill the blanks - Michael Douglas is, at best, passable as her romantic interest. Richard Widmark is good as Doctor Wheeler's mentor. The movie also shows many future stars and respected actors like Ed Harris and Tom Selleck in small roles, although the latter one looks rather lame.

That wasn't the only flaw of this film. The plot worked very well until the very end, with the unexpected plot twist which had reduced Doctor Wheeler from the heroine into typical "damsel in distress". And the ending was rather weak and not too cathartic. But that plot twist at the end was also an opportunity for the authors to allow some of the characters to explain the ethical challenges - the basis for the plot premise. That same premise looked preposterous twenty years ago, but today, it is taken for granted as a sad fact of life. Perhaps that, more than everything else, makes this film so scary and so effective after all those years.