Are there any other disorders/diseases as complex as or more complex than stutter?

Are there any other disorders/diseases as complex as or more complex than stutter? I came up a question: Is stutter alienatedly complex so that no other disorders/diseases can be compared or there are other as complex as or more complex disorders/diseases than stutter? I'm not an expert or something but as far as I know stutter is the most complex disorder/disease I have known of but on this earth too many disorders/diseases for human to overcome so I guess stutter is not the final BOSS LOL