I felt the story was good it just needs a few tweaks here and there to avoid run ons. Infamous threw me off at first just due to the intent behind the definition. After re-reading your lore I was able to grasp that you meant she was famous in a bad way but not famous for bad things. Almost as if they all teased her. This is a theme that you approached in the second paragraph. I really felt that the tone and mood of this piece shied towards desperation and wanting mainly applied to escape, whether she wanted physical or mental escape is up to the reader to interpret. I found that to be a nice touch of symbolism, metaphor, imagery, etc.
I saw you didn't like your passive; however, I found your passive to be relatively balanced with the exception of the massively large range of 2000. If you were to lower this amount to 900 or 1000 I feel it would be better suited for LoL. This is due to 1000 is if I am accurate just within sight range. If you don't have sight of the champ I don't think this should occur. I also think that maybe you should lower the time requirement to a more reasonable amount. But that is my opinion. With the way you are currently executing this you are forcing her to constantly be near enemies in order to gain the maximum benefit as quickly as possible. I like the idea; however, I feel you could execute it slightly differently and still be happy with it. If you want I can help you with this.
Your Q instantly reminded me of Stuffy Doll, not in its effect, but in that you are innovating a new way of establishing damage. With this spell you are establishing a theme that forces enemies to choose between one outcome or another. That is excellent since it synergizes so well with your theme of psyche. I found the wording of the spell unclear at first and had to read it several times before grasping it. Like Stuffy Doll I feel that this spell will require minor editting to wording before you get it perfect.
With that in mind I move on to your W, a spell which creates a synergy with your Q that may rival malzahar's malefic visions coincidentally the same spell as you originally compare Q to in animation sense. I think the wording of the secondary unit effect is a little confusing since you say "Target unit is also inflicted with psychosis" I think that by just saying "Secondary Unit is also inflicted with Psychosis" you can avoid confusion here. Late game damage here seems just a bit high because it is optimal to combo this move. You may wish to consider lowering the damage just a little bit not too much. Keep early game same just lower mid to late game by a few points. I'd say a nice round 200 would be fine, that 8 just drives me crazy. Return from tangent back to the synergy of the spell. I don't know if you meant to do it, but this spell is a force to seperate targets from groups in order to divide and conquer teamfights. Quite similar approach to how Zilean's bombs work.
Moving along we come to your E ability. This ability returns to the whole choose your fate aspect. Either take the damage or take the stun. I felt both were balanced since it gave the champion the option of running away or staying. This spell would work well specifically while combo'd with Psychosis cast on Neurosis. Force them to run and be stunned.
Finally your ult. I only found one problem with it. The current availability of casting it on an ally. That is not something I think you wanted. Maybe change to Target Enemy in your first sentence in order to clarify. I had to read the whole 10% sentence about 3 times before I realized exactly what it did. I should have understood the first time based purely on the fact that you said they were tethered and took damage from their allies. I don't know what it was about that sentence but it caught me in confusion for a brief moment.
Overall I felt that it was a well thought out concept that needs minor changes in order to improve it. I think with this review you could come closer to perfection.