Delusion is defined as a false, unshakeable belief that is inconsistent with one's culture or background. True delusions arise from a primary psychotic experience and cannot be explained by other factors, while delusion-like ideas are secondary and derived from another mental condition. Various dimensions of delusions have been identified, including levels of emotion, conviction, consistency and preoccupation. The development of a delusion involves stages from a changed perception of reality to the formation of an autistic worldview. Primary delusional experiences described by Schneider include delusional moods, sudden fully-formed delusional ideas, and perceptions that attribute new self-referential meanings to objects.

1.  Definition
 Vectors of delusions
 True Delusions And Delusion-like Ideas

2. Delusion
 Delusion is defined as “a false, unshakeable belief that is out of keeping with the patient’s
social and cultural background. A delusion is the product of internal morbid process and
this is what makes it unamenable to external influences.(Fish)
 A delusion is a belief that is firmly held on inadequate grounds, is not affected by rational
arguments or evidence to the contrary and is not a conventional belief that the person
might be expected to hold given his educational and cultural background. False is omitted
from this definition because in some cases a delusional belief can be true or subsequently
become true e.g. pathological jealousy (OTP).

3. The stages of delusion formation Conard has proposed five
stages in the development of delusional psychosis.
Trema: Delusional mood representing a total change in
perception of the world.
Apophany: A search for, and the finding of, new meaning for
psychological events.
Anastrophy: Heightening of the psychosis.
Consolidation: Forming of a new world or psychological set
based on new meanings.
Residuum: Eventual autistic state.
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4. Jasper (1962) has proposed three criteria of delusion:
(i) It is a belief which is held with extraordinary conviction, with an incomparable
subjective certainty;
(ii) There is an imperviousness to other experiences and to compelling counterargument;
and
(iii) The content of belief is impossible.

5. Kendler et al. (1983) have proposed several poorly correlated dimensions or vectors
of delusions. (ABCDE P.S.)
Affective response: the degree to which the patient’s emotions are involved with the beliefs.
Bizarreness: the degree to which the delusional beliefs depart from culturally determined consensual reality
Conviction: the degree to which the patient is convinced of the reality of the delusional beliefs.
Disorganization: the degree to which the delusional beliefs are internally consistent, logical and systematized.
Deviant behavior: acting out on beliefs
Extension: the degree to which the delusional belief involves areas of the patient's life.
Pressure (Preoccupation): the degree to which the patient is preoccupied and concerned with the expressed
delusional beliefs.
Systematization: the framework created around the primary delusion.

6. True Delusions And Delusion-like Ideas
True delusions are the result of a primary delusional experience that cannot be deduced from any other morbid
phenomenon, while the delusion like idea is secondary and can be understandably derived from some other morbid
psychological phenomenon – these are also described as secondary delusions. Thus to summarize, delusions are
divided into true (primary) delusions and delusion like ideas (secondary delusions).
Primary delusion- a primary delusion is one that appears suddenly and with full conviction but without any mental
events leading up to it. The essence of the primary delusional experience (also termed apophany) is that a new
meaning arises in connection with some other psychological event. Primary delusional experiences tend to be
reported in acute Schizophrenia but are less common in chronic Schizophrenia, where they may be buried under a
mass of secondary delusions arising from primary Psychiatric history taking delusional experiences, hallucinations,
formal thought disorder and mood disorders.

7. Schneider (1959) suggested that these experiences could be reduced to these forms of primary delusional experience:
 In the delusional mood (or atmosphere) the patient has the knowledge that there is something going on around him that
concerns him, but he does not know what it is. Usually the meaning of the delusional mood becomes obvious when a
sudden delusional idea or a delusional perception occurs.
 In the a delusion appears fully formed in the patient’s mind. This is also known as an autochthonsudden delusional idea
(delusional intuition) ous delusion. It is not in itself diagnostic of Schizophrenia because sudden ideas ‘out of blue’ or
‘brain-waves’ occur in various mental illnesses such as depression, personality disorders, organic and epileptic psychosis
and even in normal individuals.
 The delusional perception is the attribution of a new meaning, usually in the sense of self-reference, to a normally
perceived object. The new meaning cannot be understood as arising from the patient’s affective state or previous
attitudes. This last provision is important because the delusional perception must not be confused with delusional
misinterpretation. Schneider emphasized the importance of this symptom’s ‘two memberedness’, as there is a link from
the perceived object to the subject’s perception of this object, and a second link to the new significance of this perception
(sometimes also called delusional significance).

8. Little Psychologist