Pathogenesis and symptomatology of hallucinations (delusions) of organic brain disorder and schizophrenia

Authors


  • This review article was presented by the author in Symposium of the 23rd annual meeting of Japanese Psychogeriatric Society in Kobe, 27–28 June 2008.

Professor Jun Horiguchi MD, PhD, Department of Psychiatry, Shimane University School of Medicine, 89-1 Enyacho, Izumo 693-8501, Japan. Email: jhorigu@med.shimane-u.ac.jp

Abstract

In this review article, in order to explore the mechanisms underlying the hallucinations/delusions of schizophrenia, we discuss the contribution of the following four questions: (i) can an understanding of dreams contribute to our understanding of the genesis of halluciations and/or delusions; (ii) are the mechanisms underlying psychotropic drug-induced psychoses the same as those underlying the hallucinations and/or delusions in schizophrenia; (iii) does disturbed consciousness contribute to the manifestation of psychotic features; and (iv) are the psychoses caused by organic brain disorders any different to the hallucinations and/or delusions seen in schizophrenia? We conclude that there is a strong association between drug-induced hallucinations or hallucinations associated with organic brain disorders and simple hallucinosis or fluctuations in arousal level. Because intermediate configurations and/or cross-staining phenomena exist for hallucinations and delusions, especially in schizophrenic disorders, it is difficult to isolate the hallucinations and to recognize them as being abnormal experiences.

INTRODUCTION

Elucidating the pathological conditions in schizophrenia is a major problem, especially for neuropsychiatrists. In the present review article, we consider the four points of view outlined below to explore the mechanisms underlying the hallucinations (delusions) of schizophrenia.

1. Can the study of dreams contribute to our understanding of the genesis of hallucinations and/or delusions?

2. Are the mechanisms underlying the hallucinations and/or delusions in schizophrenia the same as those reponsible for the hallucinations and/or delusions caused by psychotropic drugs?

3. Do differences in the absence and/or presence of disturbed consciousness, including sleep, explain the psychotic features?

4. Is there any difference between the hallucinations and/or delusions caused by organic brain disorders and those seen in schizophrenia?

Readers should note that the present review article may contain different opinions from those expressed in other articles. The authors' opinions described herein are based mostly on clinical experience. A case report is presented that explores the four questions given above. A discussion follows regarding the intermediate position between hallucinations and delusions, as well as the contribution of the underlying mechanisms of both to the abnormal experiences of schizophrenia.

CASE REPORT

A 65-year-old woman presented with a chief complaint that ‘A family of six lives in my room’. The patient's oldest son has been worried about her since she was about 62 years of age because of problems she had when sleeping, such as troubling dreams followed by waking in the middle of the night, talking in her sleep, and calling out when she got up in the middle of the night.

After approximately 2 years, a tremor appeared in the patient's right hand. She was diagnosed with Parkinson's disease and subsequently started receiving drug treatment. After 1 year treatment, when she was 65 years of age, the patient started calling her oldest son to tell him things such as ‘I feel an old lady is in the bathroom’ or ‘it seems like a young child stood beside my pillow’. Moreover, she also stated that ‘I heard a murmur of voices in my house’, ‘an adult couple with their two children lives in the second-floor room’, or ‘two old ladies also live in the first-floor room’.

A process of organizing delusions

Can the study of dreams contribute to our understanding of the genesis of hallucinations and/or delusions?

In this case, the patient did experience sleep abnormalities prior to receiving drug treatment. The first symptoms in this case were nightmares and REM sleep disorders, such as troubling dreams followed by waking up in the middle of the night, talking in her sleep, and calling out when she got up in the middle of the night. There are two components to the sleep-related hallucinations. The first appears in the transition from wakefulness to sleep. The representative symptoms are narcolepsy and phobic hypnagogic hallucinations. Diagnosing these includes looking at clear dreams, active visual hallucinations, and sometimes delusions. In addition, hallucinations induced by sleeping pills should not be forgotten; allochroism, allaxis, and/or parameter visions appear when a person falls asleep after taking medication. Patients do not remember these visions.

The second component emerges during REM sleep, as in the present case, who experienced nightmares and/or REM sleep behavior disorder. Strong psychomotor excitations initially appear and sometimes the patients remember their experiences during the dream in the REM sleep behavior disorder. Those hallucinations, especially the visual hallucinations of schizophrenia, do not appear to be related with the patient's dream and/or sleep.

Are the mechanisms underlying the hallucinations and/or delusions in schizophrenia the same as those reponsible for the hallucinations and/or delusions caused by psychotropic drugs?

After starting treatment with l-DOPA agents, the hallucinations experienced by our patient changed. Substantive awareness appeared in abnormal awareness, such as ‘I feel an old lady is in the bathroom’ and ‘it seems like a young child stood beside my pillow’. ‘Abnormal awareness’ is a term coined by Ach in 19051 that means a state of awareness of non-symbolic and non-sensory thought that is regarded as mental activity for healthy people. For example, when we see the word ‘bell’, we are conscious of the ‘totality of the bell’, such as the sound of the bell and its coldness, all at once even though we may not imagine a representation of the meaning of ‘bell’.

Abnormal awareness, such as substantive awareness, was defined by Jaspers in 1913.2 It refers to a substantive sensation where we vividly feel the existence of a human and/or another object, even though we do not have the input of any sensory factors, such as seeing the other person or object. Jaspers stated that the phenomenon of substantive awareness is a characteristic symptom of schizophrenia.2

There are also other types of philosophical and delusional awareness within ‘abnormal awareness’. These symptoms are located somewhere between hallucinations and delusions. It is important to remember is that the abnormal awareness symptoms of schizophrenia are also seen in 39% of Parkinson's patient treated with l-DOPA agents.3

Do differences in the absence and/or presence of disturbed consciousness, including sleep, explain the psychotic features?

In the present case, auditory hallucinations gradually appeared as part of her sumptoms of substantive awareness, as demonstrated by her comment ‘I heard the murmur of voices in my house’. In addition, the patient remembered these abnormal experiences but did not maintain a critical ability to conclude that they were abnormal experiences. Consequently, the auditory hallucinations did not appear to be a neurological manifestation of disturbed consciousness; rather, it was considered a symptom of the patient's hallucinosis.

Separate from the disturbed consciousness, auditory and/or visual hallucinations may occur as a type of ‘release phenomenon’ following sensory deprivation because of a disorder and/or decreased of sensory function (e.g. auditory or visual disturbances in elderly people).

Is there any difference between the hallucinations and/or delusions caused by organic brain disorders and those seen in schizophrenia?

The delusions expressed by our patient, such as ‘an adult couple with their two children lives in the second-floor room’ or ‘two old ladies also live in the first-floor room’, are typcial of the ‘Phantom Boarders’ delusion, introduced by Rowan in 1984.4 This type of delusion is a type of persecution delusion that is part of late paraphrenia.5,6 It is common in middle-aged women living alone and is strongly related to loneliness and isolation. A concept of late paraphrenia is not included in organic brain disorders. Although our patient is not late paraphrenic, her delusions are characteristic of this condition.

EXPRESSION AND FLUCTUATIONS OF HALLUCINATIONS (DELUSIONS) IN ORGANIC BRAIN DISORDERS

The aforementioned case was presented as a typical example of organic brain disorder. The type of hallucinations and the mechanisms underlying them in organic brain disorders are based on decreased cognitive function caused by the organic brain disorder and/or fluctuations in the arousal level with sleep disorder. It is often the case that the type of hallucination is modified according to fluctuations in arousal level. These symptoms always fluctuate because they can be either unaccompanied by disturbances in consciousness or they can be accompanied by clearly disturbed consciousness, such as delirium and amentia.

HALLUCINATIONS AND DELUSIONS IN SCHIZOPHRENIA

Self-awareness and the disorder

In 1948, Jaspers divided self-awareness into four categories.7 He described that: (i) feelings of depersonalization worked against ‘active self-awareness’; (ii) second self and multiple personality worked against ‘unitary self-awareness’; (iii) self-identification disorder in the past and present worked against ‘self-awareness of identity’; and (iv) an inability to clearly distinguish between subject and object, egorrhea, broadcasting of thought, mind-reading, and experience of possession worked against ‘self-awareness of the borderline between self and others’.

Self-awareness and hallucinations in schizophrenia

Autochthonous ideas appear when thought activity decreases followed by a waning of the sense of self-belonging. Sometimes it is manifested as a visual hallucination of thoughts. Gradually, patients complain of a withdrawal of thought, broadening of thought, mind-reading, or hearing auditory hallucinations then imperative auditory hallucination. At this stage, the patient can manifest passivity thought and/or act. In clinical practice, auditory hallucinations possibly appear in the evenings when a patient's level of activity (arousal) decreases and/or when a patient's consciousness decreases and/or during hora decubitus.

As above, the core foundation of the mechanism underlying the expression of hallucinations and delusions in schizophrenia is a self-awareness disorder, especially an ‘active self-awareness’ disorder, in which the abnomal awareness and various thought disturbances are based on autochthonous experience. That is, echoing of output–thought, visible thought, withdrawal thought, broadening of thought, and mind-reading. If it was a product of auditory hallucinations, it will come out as an auditory hallucination leading to a paranoid experience. Thus, the hallucinations in schizophrenia are difficult to isolated and to identify as being an abnormal experience. There have been many studies into the relationship between cerebral regions and psychotic symptoms in schizophrenia and in the elderly with dementia, including those with Alzheimer's disease.8–11 However, from our point of view, careful interpretation is required when evaluating data from neuroimaging studies that are exploring the central origin of hallucinations.

CONCLUSIONS

In conclusion, we believe that: (i) drug-induced hallucinations and hallucinations of organic brain disorders are strongly correlated with simple hallucinosis or with fluctuations of arousal levels, disorders in sleep–wakefulness, and disturbed consciousness; (ii) self-awareness disorders play a major role in the output of hallucinations (delusions) in schizophrenia; (iii) intermediate configurations and/or cross-staining phenomena exist between hallucinations and delusions; (iv) taking the previous point into consideration, the hallucinations in schizophrenia are difficult to isolate and identify as being an abnormal experience; and (v) careful interpretation is required when evaluating data from localization studies exploring the central origin of hallucinations.

Ancillary