<prompt> Which of the following is not a disorder of form of thought?DerailmentTangentialityThought blockLoosening of association  <response>: Ans. c. Thought block Ref: Kaplan Synopsis 10e p234; CDTP 2nd106, 274, 749Thought block is a disorder of stream, not a disorder of form.ln format thought disorder, the structure or form of thought is disordered. It includes preservation, flight of ideas clang association, puns, rhymes, loosening of associations, derailment, vorbeireden, verbigeration word salad; tangentiality, transitory thinking, substitution, omission, rivelling, desultory thinking, neologism, poverty of speech and poverty of content. Whereas thought block is mainly a disorder of flowstream of thoughts.Thought DisordersDisorders of form Form is the structure of thoughtDisorders of stream Flow of thoughtDisorders of Possession Control of thoughtDisorders of content Themes Loosening of association Derailment Tangentiality Substitution Omission Transitory thinking Driveling Desultory thinking Neologism, poverty of speech Poverty of content of speech, word salad Flight of ideas Thought block Circumstantiality Prolixity Thought retardation Preservation Obsessions and compulsion Thought insertion Thought withdrawal Thought broadcast Delusion of reference Persecution, misinterpretation Grandiosity Guilt Nihilism Depressive cognitions Overvalued ideas 