Modern psychiatry began in the mid to late 19th century when several syndromes including paranoia were consolidated by Emil Kraepelin and called dementia praecox,1 later renamed ‘‘schizophrenia’’ by Eugene Bleuler in 1911.2 The ‘‘Kraepelinian dichotomy’’ described 2 separate diseases to explain severe mental illness, schizophrenia and manicdepressive insanity or bipolar disorder.1 Bleuler2 and then Schneider3 emphasized that psychosis, to include a paranoid delusional system, was pathognomonic of schizophrenia and discounted the diagnostic implications of mood symptoms. A very different idea was presented in 1905 when Specht4 said that all psychoses were derived from mood abnormalities.5 Kraepelin had also linked paranoia and mood when he used the term ‘‘paranoid depression’’ to describe an illness with a high rate of suicide, severe depression, paranoia, and auditory hallucinations.1,5 The 1933 introduction of schizo affective disorder6 recognized the diagnostic relevance of mood symptoms in psychotic patients, linked schizophrenia (psychosis) and mood disorders, and eroded the concept of the Kraepelinian dichotomy.7–11 Some now consider schizoaffective disorder to be a psychotic mood disorder and not a subtype of schizophrenia or a separate disorder.7–12 In addition, certain authors in the United Kingdom have associated paranoia with depression and delusion al guilt.5 One group in the 1970 simplied that about 95% of their sample of patients diagnosed with paranoid schizophrenia actually suffered from mania because ‘‘classic bipolar’’ patients were observed to suffer paranoid delusions.