Robert Clark is a patient on the Oswald Asylum. It is unknown why he's a patient in the asylum, and for what's shown appears to only have minor behavioral abnormalities that could simply be playfulness (him trying to attach paper on the television and talking in a funny way). It could even be that his odd behavior only occurred after the failed lobotomy.
While not much is known about Robert's issues and reasons for being locked away in the asylum, the shadow looming over the television talks about people deceiving him with kind words while in truth tormenting him, such as saying "you're beautiful" while giving him "poison" to eat, and telling him he's loved while teaching him to hate himself. This could imply some trust issues, inferiority complex, and self-loathing.
For some reason, it was decided that lobotomy was the best solution for Robert. However, Robert woke up from failed anesthesia halfway through the surgery, and it was halted. This may have caused some trauma, perhaps being the sole reason for his odd behavior in the first place.