Our thought process follows a rational goal directed and logical stream except in dreams. The thought process may be affected by psychiatric disturbance and shows the following symptoms:


– Pressure of thought: subjective experience and objective

– Poverty of thought.

– Thought blocking:

II. Disorders OF FORM OF Thought

1. Flight of Ideas – Includes clang association, rhyming, punning, and responding to distracting cues in the environment.

2. Loosening of associations – a loss of the normal structure of thinking.

–           Knight’s move (derailment)

–           word salad

–           verbigeration (verbal stereotypy)

–           alogia (illogicality)

–           agrammatism

–           fusion (bringing together heterogeneous elements)

–           neologisms

–           circumstantiality

–           overinclusiveness

3. Perseveration

1.Disordered form

Autistic thinking: Here thought is directed by inner fantasies and is associated with social withdrawal. Thinking here is less subject to correction by reality than is normal thinking.

Blocking: Cessation in the flow of thought or speech; occurs in schizophrenia.

Schizophrenic thought disorder: Disturbance in association leading to subtle discontinuities in the flow of speech (knight’s move, derailment). It may lead to neologisms which is newly invented words or incoherence when severe.

Pressure of speech: Speech is voluble and difficult to interrupt. Often related to anxiety.

Flight of ideas: High speed speech with leaps from one subject to another which are connected tenuously together. Speech is distractible in response to environmental stimuli. Speech is voluble and often includes punning. This is common in hypomanic illness.

Clang associations:  Connections between thoughts are dictated by chance sounds of words rather than their meanings. This is often associated with flight of ideas.

Retardation: Slowing of speech as in depression when it may be part of a general picture of psychomotor retardation.

Mutism: The patient refuses to speak whether for conscious or unconscious reasons.

2. Disordered content

Obsessianal ruminations

Rumination is the pathological presence of a persistent and repetitive thought, feeling or impulse that cannot be eliminated from consciousness by deliberate effort. On quiet reflection the patient recognises that it has no rational basis and that it is due to his own psychological processes rather than some outside influence. Resistance to it is accompanied by anxiety. In obsessive-compulsive neurosis it may lead to severe disturbance in behaviour.


A delusion is a belief that is firmly held against all evidence to the contrary and which is out of context with the person’s educational and cultural background. It is incorrigible, often centred on the self (egocentric) and usually, but not necessarily, false.

A false conviction which is not understandable with reference to the patients educational, cultural and social background.


  • Paranoid: ideas of persecution and injustice.
  • Depressive: morbid guilt, self-blame, futility.
  • Hypochondrial: concern with bodily and personal attributes and may be bizarre.
  • Grandiose: over-estimation of personal qualities, abilities, and finances (as in hypomanic illness).
  • Passivity: abnormal influences on bodily processes by outside agencies (as in schizophrenic illness).
  • Reference: excessive focus of attention from others often associated with undue sensitivity or paranoid ideation.
  • Autochthonous (apophanous): sudden onset, fully elaborated apparently not related to situations or current preoccupation (in schizophrenia).
  • Secondary: follows some other morbid experience. For example, severe depression with morbid guilt may lead to belief that others will share that view of him and behave towards him accordingly.
  • Sysmatised: usually in chronic schizophrenic psychosis, when a rational internal consistency between various delusions is developed.



Delusions of reference


Guilt I worthlessness





Sexual or amorous


Delusional misidentification

1.  Capgras Syndrome – The patient believes that someone dose to them has replaced by an imposter pretending to be that person.

2.  Fregoli syndrome – The patient falseiy identifies strangers as familiar people. Altemativeiy (Oxford text), the patient believes a number of people have been replaced by a single persecutor in disguise.

3.  Intermetamorphosis – the patient believes that a familiar person has been transformed into a misidentified stranger and claims as evidence shared physical and psychological similarities..

4.  Subjective doubles – the patient believes that another person has been transformed into the patients own self.

Communicated delusions

1.         Folie imposee – Associate (A) recovers after separation from the Principal (P).

2.         Folie communique – A retains ideas despite separation from P.

  1. Folie induite – delusions from P are added to A’s mental state: A was, however, psychotic before P.
  2. Folie simultanee – delusions develop simultaneously in A and P.

Delusions of control

Thought withdrawal / insertion

– Thought broadcasting

– Passivity of affect, drives, volition.

– Somatic passivity – described as “alien penetration” in the PSE. it may be accompanied by a somatic hallucination.

Primary and secondary delusions

–  Causal use of these terms

–  Autochthonous idea I delusion

Delusional Mood

A feeling of foreboding that some sinister event is going to happen. Not actually a delusion.

Delusional Perception

A delusional meaning or significance is attached to a normal percept – self-referent, momentous, urgent and of overwhelming personal significance.

Delusional memory

A delusion which is presented as an event or an idea which is remembered from the past rather than happening in the present.

Overvalued idea

An understandable idea pursued by the patient beyond the bounds of reason. Differs from obsessional ideas in that it is not perceived as senseless or unwanted.