http://www.helpguide.org/articles/schizophrenia/schizophrenia-signs-types-and-causes.htm
The positive symptoms of schizophrenia (delusions, hallucinations, and disorganized speech)
negative symptoms of schizophrenia (apathy, social withdrawal, and low energy)
Conditions that can look like schizophrenia
Mood disorders – Schizophrenia often involves changes in mood, including mania and depression. While these mood changes are typically less severe than those seen in bipolar disorder and major depressive disorder, they can make diagnosis tricky. Schizophrenia is particularly difficult to distinguish from bipolar disorder. The positive symptoms of schizophrenia (delusions, hallucinations, and disorganized speech) can look like a manic episode of bipolar disorder, while the negative symptoms of schizophrenia (apathy, social withdrawal, and low energy) can look like a depressive episode.