<prompt> A patient of Schizophrenia on neurolepts, his psychotic symptoms gets relieved but developed sadness, talks less to others, remain on bed, all of following are likely causes except:ParkinsonismMajor depressionNegative symptoms are still persistingHe is reacting to external stimuli  <response>: D i.e. He is reacting to external stimuli Post psychotic depressive disorder of schizophreniaQ occurs only during residual phase of schizophrenia in 25 Differential diagnosis of post psychotic depressive disorder of schizophrenia are - Residual phase negative symptoms of schizophreniaQ - Adverse effects eg. parkinsonism, akinesia, akathisia of antipsychotic drugsQ - Schizoaffective disorder - depressive type 