Ottensen said:
I saw that on the extras features of the dvd!!! They included the alternate ending with director's commentary 
In addition to opening the public forum on adultery (I remember when the movie and the topic made the cover of TIME) the Alex Forrest character became the pop culture poster girl for extreme Borderline Personality Disorder. While many psychiatrists would argue that it's not an appropriate diagnosis because Alex (as a movie character) was so extreme, a lot of research papers have been convincingly written to show how she at least exhibits general characteristics of someone who is afflicted with this disorder ( although yes, they really made her extra wackadoo for cinematic effect). An excerpt from a research paper at papermasters.com:
Personality Disorder found in Fatal Attraction
Several years ago the movie “Fatal Attraction” brought public attention to a specific personality disorder termedBorderline Personality Disorder. In the film starring Glenn Close and Michael Douglas, the female character played by Glenn Close suffers from Borderline Personality Disorder. The basic plot of the movie begins with Alex Forest (Glenn Close) and Dan Gallagher (Michael Douglas) having a weekend affair while Mrs. Gallagher is out of town. When Dan leaves Alex’s apartment at the end of the weekend the first display of Borderline Personality Disorder is revealed. Alex kicks him out in a sudden rage then returns to the doorway completely calm and almost sweet with her wrists cut. Completely consistent with a symptom of Borderline Personality Disorder, fear of abandonment, the afflicted individual will often make desperate attempts to maintain a relationship. By attempting suicide, Alex is able to keep Dan at her place another night.
This episode is congruent with another symptom, which is the inability to control sudden impulses. When a situation appears out of control for the sufferer they will attempt an act of self-destruction such as Alex cutting her wrists. This first episode of Borderline Personality Disorder in the movie also presents unstable emotions, which is another significant symptom. In a matter of minutes, hours or days the sufferer can change emotions from complete euphoria to sudden rage. This was evident in Alex’s fit of anger when Dan said he must leave.
Unfortunately, in the film “Fatal Attraction”, Borderline Personality Disorder is shown to the extreme. For instance, when Dan Gallagher tells Alex Forest that they are through, she begins to stalk and harass Dan by calling him at all hours of the day and at work and home. When she finds out she is pregnant and that Dan wants no part of the baby, her disorder begins to get violent. Individuals suffering form Borderline Personality Disorder rarely go to the violent extremes as portrayed in the movie. Alex kills the Gallagher’s pet rabbit and boils it in a pot in their kitchen. She also attempts to kill Mrs. Gallagher in the final scenes of the movie. Although some sufferers can become violent to themselves or others, the majority of Borderline Personality Disorder patients do not display this extreme behavior. Borderline Personality Disorder is the most common of the Personality Disorders, afflicting at least 2% of the total population. Statistics would point to out of control violence if every Borderline Personality Disorder patient was as violent as Alex Forest in the movie “Fatal Attraction”. In reality most sufferers do not go to this extreme.
[Edited 8/23/10 12:04pm]
I think the diagnosis of BPD is a bit of a stretch based on the limited interaction that Alex had with others besides the object of her affection. Alex' personality could be the result of a multitude psychiatric disorders. She was a bit delusional, and most people with BPD are pretty lucid. Of course there are co-existing disorders but to really determine a BPD dx one would have to see her engage in a relationship with more than one selfish MF'er who took advantage of her. BPD individuals not only lack impulse control and have untameable rage, but they engage in "splitting" (good object vs. bad object) and many other things that we did not see unfold in the movie. Kinda gets me when lay people get a hold of a term that sounds "crazy' and then places that term on everyone who's erratic. Not saying you personally but just in general.