Delusions vs Hallucinations vs Illusions

Can you recognize the difference?

(A)

(B)

(C)

(D)

The answer:

So A is delusions, B is illusions, C is illusion also, and D is hallucinations. 🙂

Delusions

There are many types of delusions:

1. Delusions of influence (Believe that their thought and actions are controlled by outside force)
2. Delusions of persecution (Believe that others are trying to harm)
3. Delusions of reference (Believe that some events in the environment have special meaning to, and directed at the patient)
4. Grandiose delusions (The patient’s feelings of having special power and knowledge or special relationships with important figures)
5. Somatic delusions (Feelings that the body has been manipulated by outside forces)
6. Delusion of love (Belive that he has a special romantic relationship with a public famous figure)
7. Nihilism (Patient believe that the self world and even time has been lost or destroyed)

Illusions

Illusions may occur more often when attention is not focused on the sensory modality, or when ther is strong affective state. For example, in a dark, a frightened person is more likely to perceive the outline of a bush as that of an attacker.

Hallucinations

Hallucinations are not restricted to the mentally ill. A few normal people experience them, especially when tired, also occur in healthy people during transition between sleep and waking; they are called hypnagogic while falling asleep or hypnapompic while awaking.

• Auditory hallucinations is the most common type of hallucinations in psychiatric disorders. May be noises or voices, it can be heard clearly or indistinctly, they may seem to speak words or phrases or sentences. Hallucination may be inferred when the patient appears to be talking in response to voice and may whisper, mutter to himself incomprehensively, or talk normally or shout out loudly as occurring in schizophrenics.

NOTE: Auditory hallucinations are one of the diagnostic criteria of schizophrenia and other psychotic disorders.

• Visual hallucinations may be elementary or complex. Visual hallucinations are experienced as located outside the field of vision (eg, behind the head) or involve experience beyond the sensory range (eg, being able to look out the window and see someone in distant city). Visual hallucinations are seen in dissociation and conversion disorder, severe affective disorder, organic mental conditions, substance abuse and schizophrenia, but the contents of the visual hallucination are of little diagnostic significance.

NOTE: isolated visual hallucinations should always raise the possibility of an organic cause (medical disorder or drug abuse) and investigations should be done.

• Tactile hallucinations or haptic hallucinations generally are of little diagnostic significance. Examples like sensation of being touched, sensation of insects moving under the skin occurs in cocaine abuse and occasionally in schizophrenia.
• Hallucinations of taste and smell are infrequent. They may occur in schizophrenia and severe depressive disorders, but they may suggest temporal lobe epilepsy or irritation of the olfactory bulb or pathways by tumor, so their presence indicate medical investigation.
• Hallucination of deep sensation may occur as feelings of the viscera being pulled upon or distended, or of sexual stimulation.

 

Situation 1

1. Mrs Trevor Bentley went to her sons general practitioner concerned about changes in her son’s behaviour over the preceding 9 months. Trevor was in his final year at University reading business studies when he decided, for no clear reason, not to return for the summer semester. His parents and younger sister had noticed that Trevor was not his normal self. Unusually for Trevor he was often awake late into the night playing loud music in his room or out at night clubs until the early hours. His self care had deteriorated and he had lost considerable weight. At times he suddenly became very agitated and excited and made vague statements about how the ‘oldie’ neighbours were getting at him. On several occasions he was noticed to be laughing and talking to himself.

NOTE:

• People surrounding Trevor was affected
• More than 6 months
• Impairment of volition during summer semester
• Marked occupational or social deterioration
• Impaired overall functioning (self care)
• Psychomotor excitement (loud music, night clubs, agitated, excited)
• Poor perception to others

2. Trevor was the middle of 3 children with an elder brother and younger sister. As a child he was always a little different from his siblings, being quieter and having fewer friends. However, he did well academically at school and went on to University. Trevor’s parents emigrated from Jamaica in 1952 to find work in the UK. Trevor has 2 cousins living in London who have had ‘nervous breakdowns’ and spent periods in psychiatric hospitals. Trevor’s mother suspected that he had been smoking cannabis and wondered if he was taking any other illicit drugs. During the consultation Trevor was supposedly in the waiting room, but when the GP asked to see him, he had gone.

NOTE:

• Family history of emigrants
• Lower socioeconimic status
• Abusing drugs and alcohol
• Non-white
• Cousins of the same disease
• 15-25 age of patient (university now)

3. The GP contacted the consultant psychiatrist to arrange a home visit. They found Trevor at home in the front room. Trevor had placed a sheet over the television. Trevor told the psychiatrist that for the last few months he had heard the neighbours talking about him. He believed that they were trying to control his thoughts and actions using devices called ‘fleximeters’. He was convinced that the neighbours sent messages to him through radio waves that penetrated the television. Sometimes he could smell the electricity coming from next door. He found it difficult to explain why the neighbours should do this, but wondered if they were trying to harm him because he was black and successful, He believed that his mind was ‘super strong’ but being weakened by the radio waves. The psychiatrist suggested that Trevor attend the day hospital for a week or two for further assessment. Trevor became angry and refused. He accused the GP and psychiatrist of not listening to him and wanting to lock him up because he was black. The GP and psychiatrist discussed his mental state and whether he needed to be assessed under the Mental Health Act 1983.

NOTE:

• Auditory hallucination
• Delusions of persecution
• Somatic delusions
• Olfactory hallucinations
• Poor perception of others

4. Six months later Trevor’s mother visited the GP. During this toe Trevor spent 6 weeks as an inpatient in his local psychiatric unit. His delusions and hallucinations resolved within 4 weeks of admission. He had not returned to University and spent much of his time listening to music or in bed. He complained of restless legs. His mother wanted to know whether Trevor would be able to finish his studies and how long he would have to continue taking the haloperidol tablets that the hospital had given him.

NOTE:

• Dyskinesia as side effects of haloperidol

5. Nine months later Trevor attends a local community mental health centre, his mother is concerned that he is wasting his life and suspects that he is continuing to use illicit drugs. She admits that she gets very frustrated with him. He is visited by a community psychiatric nurse and seen in care programme meetings. He is on the waiting list for the ‘family intervention package’. His hallucinations returned 2 months after stopping the haloperidol and the question of which drug to restart is being discussed.

NOTE:

• Relapse

Diagnosis: Schizophrenia

Differential diagnosis:

1. Medical or neurological disorders
2. Mood disorders
3. Delusional disorders
4. Personality disorders
5. Mental retardation