The diagnostic implications of formal thought disorder in mania and schizophrenia: a reassessment

The authors compared nine manic patients exhibiting formal thought disorders (tangentiality, neologisms, drivelling, private use of words, and paraphasias) with 102 manic patients without these thought disorders and with 31 schizophrenic patients. Manic patients with formal thought disorders tended to have more "schizophrenic" symptoms than did manic patients without formal thought disorders, but both groups improved significantly more during the index episode than did the schizophrenic patients. Although the prevalence of flight of ideas was high in mania, narrowly defined formal thought disorder was rare, suggesting that precise definition and description of thought disorders would be helpful in distinguishing mania from schizophrenia.