There is a lot of evidence both for and against the Expressionless Woman incident. First off, examine the appearance. The necessary plastic surgery to present such an appearance wasn't readily available in 1972. However, it is possible to cleanly shave the facial hair and create that same appearance with available cosmetics at the time. Also, she was wearing a bloody white robe. Given a lack of description, I am going to presume that it was some form of medical robe of the sort that was used during that time period in both hospitals and research facilities. In the picture, the clothing shown is not bloody indicating that they either changed her robe or the picture was simply a recreation.
Next, consider her state when found. It sounds to me like she was in some sort of catatonic or near-catatonic state as she did not provide resistance until the threat of sedation was presented. She may have had some sort of brain damage, may have been under the influence of some sort of drugs, or might have been some type of then-undiagnosed autistic. Any of those stimulus could provide this sort of reaction.
When threatened with sedation, she reacted with strength described as "extreme force". Again, we look to drugs or autism, both of which can present such a reaction given certain stimulus. That reaction would also explain the apparent strength and speed which she would have had to exhibit to attack the doctor and security forces effectively.
Her other behavior (the brief discourse and and reactions to others that she eventually exhibited) are most effectively explained as some manner of delusion, again either stimulated by drugs or some form of psychosis. A drug such as PCP combined with some form of powerful hallucinogen could easily have caused her to not only attack and attempt to consume a kitten but also the attack upon the doctor and the security forces.
There are logical inconsistencies. How did they not notice her teeth when removing the kitten from her mouth. It's possible they simply didn't notice as they were concerned with other things at the moment, or perhaps her mouth simply closed to fast for them to see. Likewise, even a drugged-out or autistic woman is unlikely to have had the necessary strength to lift multiple other humans who were actively trying to restrain her. Even with large amounts of adrenaline in the system, and even if that adrenaline were supplemented by a drug of some sort, the physics simply don't work out. Finally, how did the doctor relate his last view to the recorder of the story? While it is possible that he might have told it to another person working at the hospital with his last gasps, it seems inconsistent with the way the story is being told.
All that said, there are a few inexplicable occurrences as well. Primary among them is the reaction of other humans to her. This suggests a triggered fight-or-flight reflex, similar to the uneasiness that most people feel in a situation where intangible danger threatens. If you're a paranoid, you know the exact feeling. Then there is her initial appearance. The bloodstain is clearly from her "dinner" but the clothing itself would indicate that she is either an escapee from a hospital or sanitarium or some sort of lab. The picture presented with most versions of the story seems likely to be some form of recreation.
Based upon the evidence, while the story is creepy and the picture is downright scary, the logical inconsistencies in the story render it extremely unlikely to the point of likely untruth.