I had a truly horrific experience with Keppra: about a year and a half ago I suffered some virus that left me with post-viral encephalitis and lesions in my right temporal lobe, which resulted in a seizure disorder. I spent two weeks in the hospital while subjected to every test known in an effort to determine the pathogen (including five MRIs, two spinal taps, two CT scans, a PT scan, myriad blood tests...) only to be told "It was some virus that is either not know by medical science or some mutation of one that is known."
For my first two days in the hospital I was put on Keppra and shortly thereafter became clinically psychotic. I remember some of it, such as lying on the bed, screaming and raving, insisting that there was a force field against the left side of the bed that I was trying to roll my body, with great force, against; of course there was no force field, and it took all of my wife's strength to push me back onto the bed for the four hours or so I kept pushing against her. I also started screaming at her saying, "YOU KNOW ME BETTER THAN ANYONE, AND IF YOU DON'T SEE THE FORCEFIELD THEN YOU DON'T LOVE ME AND YOU'VE NEVER LOVED ME!!!" I remember the neurologist, while I was standing on the bed and raving about something, saying, "By whatever God you believe in, please, please sit down!" It was only when he said, "Your father and your wife would want you to sit down" that I finally did. And he only knew to say this because before I was given any medication, I told the neurologist that if any decisions needed to be made about me, should I become irrational, first ask my father (a doctor himself), then ask my wife what should be done.
I then lapsed into a period of psychosis that I have no memory of – a period that my wife said was so horrific that she doesn't want to tell me about and which she assured me I don't want to hear, so, to this day, I have no idea what I said or did. The only thing she did tell me was that I went into my bathroom (I was given a private room because the doctors were afraid to put me in a room with anyone, not knowing what I was suffering from), crouched in the corner, and cried, terrified about various aspects of my life. She said it took a large male nurse to pretty much carry me back to my bed.
I remained in this psychotic state for about 24 hours. When I regained semi consciousness I was convinced I was dead, and cried nonstop despite two friends of mine standing by my bedside trying to find every argument they could think of to convince me that I was alive. As a comedic note, one of the two friends, becoming exasperated with me, turned to the other with a smile and jokingly said, "If he's so convinced he's dead, why don't we just kill him?" (I only found out about this many weeks later, after I was fully recovered...).
Around this point my dad asked the neurologist whether my bizarre behavior / psychosis could be attributed to the Keppra,. The answer was "No." About fifteen minutes later my dad got a call from the neurologist saying, "We're taking your son off Keppra NOW." He must have Googled "Keppra psychosis," because Google will verify that it's been known to occur (though nothing as extreme as what I was experiencing). I was then put on Depakote.
There were about eight friends and family members in my room now—"now" being a relative term, because my sense of time was completely warped—and I saw everything in exaggerated colors, with the makeup of the women in the room appearing thick, fluorescent, and grotesque. Also, people kept shifting, such that one friend's wife might have appeared next to a different husband. Just when I was convinced this was reality, the couples shifted such that couples were again rearranged. Just when I was convinced that, "ok, THIS is reality, the couples shifted again. This shifting happened several times throughout the evening.
When the phantasmagoric colors and people shifting ended, the auditory hallucinations started. I heard the same four songs over and over and over and over... One was a Louis Armstrong / Ella Fitzgerald duet, the three were also real songs, but I can't remember now which songs they were. It had never occurred to me up until this point that when people "hear voices" that the voices come from outside the person's head. I had always assumed the voices were some sort of interior monologue, but the songs sounded as if they were coming from a loud radio that I could not turn off. Hours of this were making me crazier and crazier.
At this point the hospital I was at realized they did have the resources to handle me, so they sent me to a hospital that could perform a 72-hour, video-monitored EEG on me. The songs were still playing as I sat strapped in the ambulance. They were making me crazy, and I knew I could not go on much longer with them playing, let alone the rest of my life. I started telling my wife, "if the songs don't stop I'm going to fucking kill myself. I swear to god I will go to the top of a building and fucking jump off of it. I can't take this anymore: I swear to god I WILL fucking kill myself. I started punching myself in the head, tying to get the music to stop, while continuing to tell my wife that I was going to fucking kill myself. And I would have. I really would have. I realized that when people hear voices in their heads, telling them to do things, exactly how powerful those voices are.
Fortunately, shortly after arriving at the new hospital, the songs stopped. I was still very weak, and my sense of time was still very distorted. After a day or two I was talking to the neurologist, and asked her about her experience with Keppra psychosis. Whereas the first neurologist was unfamiliar with it this one said, "Oh, we see it all the time – we call it the 'Keppra Crazies,' though I have NEVER seen or heard about a case as severe as yours."
The EEG revealed that I definitely had disturbances, and the brain MRIs revealed that I had post-viral encephalitis and lesions, primarily in my right temporal lobe, brought about a virus that, to this day, cannot be classified.
When I was relatively stable and able to act and talk coherently, I said to my wife, "I fee like this is the worst day of my life." She replied, "I feel like this one of the best." When I, surprised, said, "WHY?" She replied, "Because I have you back." Nobody knew whether my psychosis would be permanent, or what kind of life I might be confined to as a result of either the lesions and/or the results of the Keppra.
I am now on Depakote, and, other than occasional, minor hand tremors, am doing well. When forget to take my medication I have seizures. A friend of mine who is a pharmacist said, "They're called 'Side Effects' but they're not: they're effects, they're just not the desired effects."
To answer anyone's question as to whether Keppra can completely change a person's personality, the answer is yes. Absolutely, categorically yes.