the reason schizphrenia is called a thought disorder is because it affects your cognitive thinking - which is learning / memory / attention / disorganized thinking and speech / processing information / etc. thats why schizophrenia is considered the most complex and debilitating. because it can have psychosis - yea - like you mentioned but then the thought processes are messed up and then on top of that you have negative symptoms like social withdrawal and lack of desire for having relationships or say alogia which is when someone rarely talks or talks very little. or other negative symptoms. every person is different and would have a mix of different symptoms in all of these three categories of problems.