You can often use a thesaurus to get alternative words that may work better (note - longer or more complex, rarely used words do not equal more smart or more clinical), or experiment with different phrases. I'll try and help you out a bit, however.
Insanity - depends what 'insanity' you're describing. It's not really used this days to describe someone who is mentally ill, except maybe either in an offensive way or a self-deprecating way. It's much better to either describe the symptoms, or link it to an existing mental health condition.
Going insane - again, depends on what the outcome of this 'insanity' is, and what the symptoms are.
Domination is pretty clinical, depending on what you need it to say (I'm seeing a pattern here that really, I need to see these words in context to give you more help).
Pale skin - Depends what you mean - just pale, or white? Pallid or pallor are both more clinical.
Extreme paranoia is pretty much already clinical, but you would need to expand on how this paranoia shows itself.
Immovable barrier, again, is fine, looking at it with no context. In context, it may not be suitable.
Wide smile - 'an unnaturally wide smile' or 'the facial expression turns into a smile, which presents as unnaturally wide'.
Scarred is clinical - again, with no context at all.
Excitement could be use clinically, but, once more, I need context to understand better what you're trying to say.