i) Psychoses

Psychosis is a disturbance of reality testing

Psychosis is, in its broadest definition, a disturbance of reality testing.

The person's perception of what is happening in the real world is altered by the illness. There is no comparison with what is occurring in the real world.

Psychosis can be characterised by the experience of:

• delusions
• hallucinations
• thought disorder.

 

ii) Delusions

Delusions are false fixed ideas that a person holds and these ideas are contrary to their cultural, social or religious beliefs.

The person maintains the idea despite being given evidence to the contrary.

The delusional idea must cause the person to change in terms of their emotions, their behaviour or their feeling state and thought processes. They have to act on the idea.

If the person has an abnormal idea that is not consistent with their reality but it does not cause a change in behaviour or emotional experience we call that an overvalued idea. Overvalued ideas are also found in psychotic states.

Distinguishing a delusion from a confabulated memory can be difficult.  In confabulation the ideas often change according to the external stimulus (environment).  Delusions are typically fixed and consistent.

 

iii) Hallucinations

Hallucinations are the experience of perceptional phenomena in external reality where there is no stimulus in the external reality.

For example, the person will hear the sounds or voices talking to them but there is no sound in the external reality.

Hallucinations can also take the form of visual, tactile and olfactory experiences. People can have the experience of smelling things that do not actually occur.

In the past it was thought that the auditory hallucinations were found only in the schizophrenias or functional psychiatric illnesses and that the hallucinations such as visual hallucinations or sensory somatic hallucinations were more commonly found in organic states. Research in traumatic brain injury populations found auditory hallucinations were very common.

 

 

iv) Thought disorder

Thought disorder is when a person's ability to construct their ideas and express those ideas is disturbed.

For example they will have problems with regard to their grammatical construction of sentences, they exhibit clang associations where each sentence ends with the same word and has a very rhythmic quality.

Thought disorder can be difficult to diagnose in people who also have a brain injury or any other damage to the central nervous system because the central nervous system is very important for the control and production of language.

People can have a stroke or traumatic brain injury in the areas of the brain that control language and they will have a problem with production of language. This is not thought disorder, this is dysphasia. The differentiation between the two can be difficult to discern.

 

 

v) Questions

 

References:

1. Psychotic disorder due to traumatic brain injury:  DE Fujii, NP Armstrong and I Ahmed.  Chapter 13, in The Sectrum of Psychotic Disorder; Neurobiology, Etiology and Pathogenesis.  Ed D Fujii, I Ahmed.  Cambridge Press, United Kingdom.  2007.

2. Schizophrenia-like psychosis and traumatic brain injury.  PS Sachdev.  Chapter 13 in Secondary Schizophrenia.  Cambridge Press.  New York 2010.

3. Psychotic Disorder:  A Wakin, D Malaspina, M Perrin, TW McCallister, C Corcoran.  Chapter 11 : in Textbook of Traumatic Brain Injury.  Ed. JM Silver, TW McCallister, SC Yudofsky.  American Psychiatric Publishing.  Washington 2011.