The film uses some common scientific myths, such as Vernon's statement of 90% of Your Brain and when Eddie mentions his Improbably High I.Q. of four digits. Vernon is a drug dealer with no scientific credentials at all, and was simply explaining things in a simple, if inaccurate, manner. Eddie never took any IQ tests, and just pulled some random number out of his ass.
The Sequel Series has the main character scoff at the myth and comment on how everyone gets that wrong.
The series shows that the Feds are looking into it, and even tried to use it for themselves. But they couldn't control the side effects, and gave up. They have no idea where it came from or who made it.
The psychological effects of NZT seem to also vary depending on what the users starting personality is. Eddie and Brian start out as aimless slackers so they take a slightly more relaxed approach to their new abilities and search for a worthy goal. When a group of stockbrockers take the drug, they become more cutthroat and competitive and one quickly decides that Murder Is the Best Solution. When a SWAT member takes the drug, his actions are very calculated and ruthless once a decision is reached. The more aggressive personality types seem more likely to Jump Off The Slippery Slope before they can get handle on what is happening to them.
It also plays out to why Eddie and Brian are basically opposite sides of the same coin with Eddie essentially being Brian's Shadow Archetype. As it's been pointed out before, both Eddie and Brian were relatively similar before receiving NZT and obtained it and went through very similar circumstances at the start. Where things are different though, is the fact that ultimately Eddie both in the film and in the show (best shown in "The Assassination of Eddie Morra") uses NZT for acts of complete selfishness and is only really out for himself. Brian on the other hand, the first episode alone he spends pretty much the entirety of it helping others, even at immense personal risk of getting put in prison. While he did make a play to get himself exonerated, he earned Rebecca's trust along the way with his benevolent personality which made it MUCH more easy for him to basically get the abundance of crimes he was forced to do thrown out. In the end, Eddie's only true ambition is himself and how to further himself along while Brian ultimately just wants what's best for everyone else. On a WMG tilt, it's quite possible that it's the very reason Eddie keeps Brian around when he's so very hard to control. While he expresses confusion as to why Brian hangs on to his old life, the reality could be Eddie needs Brian to remind himself of his old humanity and not take one step too far.
Why didn't the police search Eddie at the murder scene? If he was a prime suspect, which he would be having found the body, they would have cuffed and searched him before taking him to the police department to make a statement and therefore have found the NZT pills he shoved into the small of his back.
Usually the person that calls the cops in the first place to report a dead body isn't treated as the prime suspect.
Eddie described his ex-wife Melissa as the smartest woman he knew who dumped him immediately. High intelligence and impulsive behavior. Those sound like indications that she was already on NZT when he met her.
There is no fridge logic here, there's an entire scene explaining this is exactly what happened.
Seeing Eddie embracing his new persona is frightening. In the film Eddie was flawed but basically a decent guy. This new version who embraced his new mission to save humanity no matter what. This is a man free of doubt, free of remorse and free of hesitation. Worse part this is due to taking NZT on a daily basis, just like Brian. Even more horrifying his change of personality is him accepting the better version of himself then his past self. He tries to convince Brian to do the same, while Brian refuses you can see the fear on his face as he realizes it may just be a matter of time before he starts to think and act like Eddie.