Then I watched the 1998 TV movie presented by Oprah.
After that I read the actual book by Theodore Isaac Rubin, available on internet free of charge right here.
So I feel quite competent to express my views on all three of them.
I cannot say if people who are not interested and have not taken any courses in psychiatry and psychology will gain much pleasure from these works or will even understand the symbolic aspects of the movies. To be honest, at times it seemed to me the actors of the 1998 movie did not quite get them either (and I'm actually talking about Brittany Murphy here). Brittany's portrayal of Lisa seems artificial. Only after reading the book I found out that Lisa was supposed to be 14, and David turned 16 during the book. However, the kids seemed much older than that in 1998 - and not because of the age of the actors (Brittany was 21 and Lukas Haas was 22), but because of the rather sexual connotations the TV movie had in comparison to the 1962 movie, and also the book.
After reading the book I realized there were actually three quite different stories of David and Lisa. First and foremost, in the way that the main characters were treated by the authors. As the book was quite vague about the parents and the causes of David's disorders, the movie makers could make whatever they wanted out of them.
The 1962 movie showed the problems as rooted in David's mother's tense and uptight personality. In many respects this character seemed very plausible and really drove the story-line forwards. Mother was aggressive, demanding, very artificial, very suppressed and suppressing. She took David away from "school" because she did not like the changes in him that had made him more outspoken and communicative. The 1998 mother (played by Allison Janney) had very different considerations. She took David out of the institution because she was shocked and scared for him after seeing the other kids. She also worried about him getting used to being institutionalized. In this version it was not the mother that was to (at least partly) blame for her son's disorders. This is very important. On one hand, it does a lot of good - taking away the stigma that the mothers of special-needs kids often get. The doctor tells the 1998 mother very early on: "Nobody blames you." We learn that David's father has died some years ago, but it does not explain or even try to explain David's problems. Surely his obsession has began much earlier.
What we don't really see in any of the movies but find in the book is that David spends at least two hours every morning getting obsessively clean, washing himself eight times, shaving again and again, devoting a lot of effort to his hair. The 1998 movie left me dubious - on one hand, David's hairdo was such that he could have done himself (surely no hairdresser could ever get near him!), but at the same time it did not fit (at least my) idea of an OCD image, it looked a bit too wild.
The book exposes Lisa's symptoms perfectly. You see immediately what the author (a psychiatrist!) needs you to notice. Lisa's character is quite incoherent, incomprehensible at the beginning. It's not rhyming she does as much as just mumble-jumble repetition of sounds and more or less made-up words. As Lisa's treatment (and relationship) progresses, her texts make more sense. This is where I blame Brittany Murphy. Or perhaps the director, I don't know. She says the rhymes like it's Shakespeare and not something just out of her head, repetitive and very childish. Her emotions seemed much too "normal", sorry for this very vague term, but she did not seem credible as a mentally severely handicapped person. Also, in the "masturbation" scene with the hand - she somehow makes it seem as if it's some other person's hand touching her, not her own discovery of her feminine sexuality. That might have been deliberate and in tune with the whole idea of making this "growing-up" story into a real sexual love story. Meanwhile, as we know, the concept of touch is of very high importance in this story - it's help and healing for some, and horror and torture for others.
This intention to romanticize the story could also be observed in the way that the makers of the 1998 movie changed the gender of at least two people - John (Lisa's "handler") into Maggie, and Simon (David's chess partner, the piano-playing boy) into Natalie. Lisa is supposed to feel some incomprehensible (to her) jealousy because of David's friendship with another person, but instead her jealousy is discreetly made into a much more "romantic", aggressive, possessive notion. No wonder! If Oprah calls this a "love story"! The book does not really lend itself to be perceived as such. It is really a story of slow and perhaps hopeless treatment and improvement, but for it to be a real love story it lacks the possibility of future for this relationship of two people at least one of which might never really reach real adulthood with all its responsibilities and accountability.
David, on the other hand, gets more and more involved with other people, even though he still avoids all physical contact. Watching the movies I wondered how the doctors had examined him, and the book did not disappoint and revealed all the medical notes. As the book is clearly Freudian, the dreams have the greatest significance. I found, however, that the clock scenes in the 1998 movie did not work at all. They were vague and even unmemorable. I suppose the director did not want to take a page straight out of the 1962 movie, but he should have! The book was quite clear about the way the dreams should have been portrayed, and if 1962 movie depicted his gory and very hostile, very aggressive, very destructive dreams as just disturbing, the 1998 scenes were not even that.
The same can be said about the statue in the museum. If we as viewers immediately, even somewhat viscerally understood Lisa's longing to squeeze into the embrace of the statue between the mother and the child (I remind - we know nothing of Lisa's family or childhood traumas), then the only thing going for the 1998 statue was the complete blankness of the face, void of any features or emotions.
All in all, the 1998 movie seemed dumbed down and lacked the logic of the 1962 movie and the book. There was no catharsis in the scene where David insists on dropping the rhyming and speaking normally. Lisa just gives in for no apparent reason, while in the 1962 movie we see how scared Lisa is of losing her defense mechanism and how she reacts to a direct order from David, as from a paternal figure. It's the same with the final scene in the museum. The 1962 gives us a step-by-step account of how Lisa's and David's trust has grown. In the 1998 movie we see David's outstretched hand as a gesture of pity or mercy, not as a result of his own learning to trust people and overcome his demons. What I loved in the final scene was the much shorter physical distance from the museum to the car. With my current (very limited) understanding of psychiatrists and other mental health professionals, the doctor would not have left everything in the hands of fate staying in the car several hundred metres away. We don't even see the person who has in many ways orchestrated the scene. The 1998 movie seems more plausible that way (the doctor could have easily observed the events on the stairs from the car without seeming indifferent or bold), and I really liked the symbolic way he opened the back door of the car for the "love couple" coming downstairs and holding hands.
Overall, a very good material for students of psychology, and I include my opinions in such detail for just one purpose - to watch the movies again and read my comments once I'm a full-fledged psychologist myself. I really loved the characters of the psychiatrist in both movies. He embodied everything I'm striving and hoping to be - a very sensitive, composed, benevolent, never judgmental professional. And Wikipedia provides a whole list of movies for further exploration of what has so clinically been dubbed "the human condition".