Hallucinations: Clinical aspects and management.

The literature on hallucinations is reviewed, including its occurrence in different psychiatric disorders, neurological disorders and normal persons. The diagnostic significance of hallucinations is also discussed. Reports of hallucinations in normal people are reviewed. The different modes of the management of hallucinations are briefly discussed.

In 1799, a Prussian bookseller of skeptical disposition named Christoph Friedrich Nicolai read a paper to the Royal Society of Berlin entitled “A Memoir on the Appearance of Spectres or Phantoms occasioned by Disease.” In this, Nicolai described how one morning in February 1791, during a period of considerable stress and melancholy in his personal life, he saw the apparition of a deceased person in the presence of his wife, who, however, reported seeing nothing. This apparition haunted him for the duration of the day and, in the subsequent weeks, the number of these figures began to increase. This paper attained cult status as a paradigmatic case throughout the psychological literature of the nineteenth century following its translation into English in 1803. Although hallucinations have been a hallmark of mental illness for centuries, they are not always pathological. Hearing one's name called aloud or hearing a person's voice but finding no one there is common. A few people describe hearing a comforting or advising voice at some time in their lives. Recently, bereaved widows and widowers may “hear” or, more commonly, “see” their dead spouse. Up to one in six people in Britain and the United States have seen, heard or otherwise experienced ghosts or spirits. Lights, visions and voices may be seen or heard during profound religious or mystical experiences, especially conversion – the experiences of Joan of Arc and St Paul are familiar examples.[1]

CLINICAL ASPECTS OF HALLUCINATIONS

Schizophrenia

The IPSS estimated that 70% of schizophrenia patients experienced hallucinations.[2] The most common hallucinations in schizophrenia are auditory, followed by visual. Tactile, olfactory and gustatory are reported less frequently [Table 1].[3] Visual hallucinations in schizophrenia have a predominance of denatured people, parts of bodies, unidentifiable things and superimposed things. Overall, one gains the impression that the schizophrenic's visual world has a surrealist fairy tale flavor, populated with things that do not exist in the real world and people who appear in a symbolic, fragmentary or attenuated form.

Table 1

Study of the prevalence and types of hallucinations in India and the USA[4]

Affective disorders

Severe depression is sometimes accompanied by auditory hallucinations, which are usually transient and limited to single words or short phrases and, generally, saying things consistent with the patient's depressed mood. Auditory hallucinations may also occur in mania. The voices usually talk directly to the patient and the content is congruent with the patient's abnormally elevated mood. Negative hallucinations have been reported in depression.

Postpartum psychosis

Symptoms of postpartum disorders center on the women's feelings about the newborn baby and her role as a mother. A hallucinating mother may simply hear her baby crying, hear voices telling her to kill her baby or accusing her of not being a competent mother.

Hallucinations induced by psychoactive substances

Psychoactive substances predominantly induce visual hallucinations. These are usually preceded by unformed visual sensations – alterations of color, size, shape and movement. The images are usually abstract, such as lines, circles and stars. Later on, the person experiences vivid and colorful images. Auditory hallucinations that are unformed and indistinct noises are heard in substance-induced psychoses. Tactile hallucinations in the form of insects crawling up the skin are experienced during cocaine and amphetamine intoxication. Reflex hallucinations are experienced under the influence of psychedelic drugs, wherein the patient perceives colorful visual hallucination in response to loud noises. After repeated ingestion of drugs, some people may experience a phenomenon called “flashbacks,” which are spontaneous recurrences of illusions and visual hallucinations during the drug-free state, similar to that experienced during the active stage of drug administration. This phenomenon can occur months after the last intake of drug.

Delirium tremens

Hallucinations in delirium tremens usually involve visual hallucinations, which typically involve different types of animals (cats, dogs, insects, snakes, rats) or signs and shapes (multicolored patterns, chalk writing on slate). Tactile hallucinations, auditory hallucinations, musical hallucinations and lilliputian hallucinations may occur. Usually, the hallucinations are unpleasant and frightening, although musical hallucinations may be pleasant.

Alcoholic hallucinosis

The syndrome is characterized by hallucinations (typically auditory, but also visual and tactile), delusions, misidentification, psychomotor disturbances and abnormal affect.

Post-traumatic stress disorder

Combat veterans with Post-traumatic stress disorder (PTSD) have more schizophrenic symptoms, particularly hallucinations and paranoia, compared with those without PTSD. Some combat veterans with PTSD have reported hearing persistent voices of a depressive nature involving cries for help or conversations concerning battle. Evidence suggests a specific association between hallucinations and childhood sexual abuse.

Borderline personality disorder

A study of 171 Borderline personality disorder (BPD) patients revealed that 29.2% reported hallucinations. Most patients expressed that the hallucinations were distressing, occurred with great frequency over prolonged periods, took control of actions or behavior (especially, self-harming behavior) and had a critical quality. Although the majority of hallucinations were auditory, visual and olfactory hallucinations were also reported.[5]

Hallucinations as a side-effect of medication,

Antidepressants such as amitriptyline, imipramine, trazodone and amoxapine can cause hallucinations,

Digoxin can cause formed and unformed visual hallucinations,

Propranolol can cause visual hallucinations,

Benztropine and trihexyphenidyl can cause visual hallucinations,

Hallucinations are reported with cimetidine, clonidine bromocriptine, levodopa, methylphenidate, antihypertensives, corticosteroids, antineoplastic and antibiotics.

Hallucination in neurological and organic mental disorders

Formed and unformed visual hallucinations occur as a result of cortical lesions involving the occipital and temporoparietal areas. Olfactory hallucinations and gustatory hallucinations are usually associated with temporal lobe lesions and lesions in the uncinate gyrus. “Crude” auditory hallucinations are more common in these conditions than formed ones. Peduncular hallucinations produce vivid, non-stereotyped, continuous, gloomy or colorful visual images that are more pronounced in murky environments. These complex visual hallucinations arise due to lesions that straddle the cerebral peduncles or involve the medial substantia nigra pars reticulata, bilaterally. Hallucinations have been reported in sleep disorders such as narcolepsy. Systemic lupus erythematosis (SLE), which involves the central nervous system, may present as hallucinations. In the above conditions the modality and content of hallucinations depends on the area of the brain involved.

Delirium

Cutting[6] reported an incidence of 34% visual hallucinations and 18% auditory hallucinations. A comprehensive literature review gave a higher figure of 40–75% for any type of hallucination.[6]

Alzheimer's disease

The prevalence rates of hallucinations in Alzheimer's disease (AD) range from 12 to 53%. Hallucinations in AD most often are visual, although auditory, tactile and olfactory hallucinations have also been observed. Hallucinations are most prevalent in the moderate to severe stages of the illness and do not seem to occur at the end stage of the disorder.

Lewy body dementia

The prevalence rates of hallucinations in Lewy body dementia (LBD) range from 46 to 65%. Although visual hallucinations are frequent, auditory, olfactory and tactile hallucinations are also reported. Pathological examination of 63 LBD patients revealed that cases with well-formed visual hallucinations had high densities of LB in the amygdale, parahippocampus and inferior temporal cortices. These temporal regions have previously been associated with visual hallucinations in other disorders.[7]

Parkinson's disease

Hallucinations are reported by 24.8–39.8% of the patients with Parkinson's disease (PD). Common factors associated with hallucinations in PD include greater age and duration of illness, cognitive impairment, depression and sleep disturbances. Although visual hallucinations are frequent, auditory, olfactory and tactile hallucinations are also reported. Hallucinations in PD are commonly neutral and non-threatening, and some patients are amused by their hallucinations. The hallucinatory experiences may include sensations of presence of people or animals or feeling of floating, and the patient may have adequate levels of insight.

Hallucinations in ear diseases

Auditory hallucinations have been reported in patients with both bilateral and unilateral hearing loss. It has also been reported in patients who have been bilaterally deaf since birth. The form ranges from irregular sound, instrumental music, songs to full-form voices. Unilateral auditory hallucination is mostly associated with ipsilateral hearing loss. In the above-mentioned cases, the majority did not have any psychiatric or organic condition that may account for these hallucinations. The theory of hallucinations secondary to chronic sensory deprivations seems to support the above findings.

Hallucinations in eye diseases

Visual hallucinations have been reported in patients with impaired vision or blindness since birth. When visual hallucinations follow marked visual acuity loss, in the absence of cognitive impairment, the condition is termed Charles Bonnet Syndrome, with an estimated prevalence of 0.5–17%. The content of the visual hallucinations range from colored shapes and/or patterns (simple visual hallucinations) to well-defined recognizable forms such as faces, animals, objects and scenes (complex visual hallucinations). The phenomenology of the visual hallucinations does not appear to correlate with the underlying ocular disease, although significant bilateral loss in visual acuity appears to be a primary trigger. In 1760, Charles Bonnet described vivid visual hallucinations in his psychologically normal visually impaired grandfather. Triggers of the syndrome include fatigue, low levels of illumination, bright lighting and stress (as with this patient). Once manifested, the images may last for periods varying from seconds to minutes to hours. Although the most commonly associated ocular pathology is age-related macular degeneration, the syndrome has been associated with cataracts, glaucoma, diabetic retinopathy and retinitis pigmentosa (as in this patient). It has also been described in cerebral disorder and as a side-effect of medication. Patients with Charles bonnet syndrome (CBS) must have formed complex persistent or repetitive visual hallucinations, full or partial retention of insight (awareness of the unreal nature of the hallucination), absence of delusions and absence of auditory or other sensory hallucinations. Single photon emission computed tomography (SPECT) studies in patients with CBS disclosed hyperperfusion areas with some asymmetrical appearances in the lateral temporal cortex, striatum and thalamus. This suggests that decreased visual acuity due to eye disease produces excessive cortical compensation in the lateral temporal cortex, striatum and thalamus, which may precipitate the development of visual hallucinations.[8]

DIAGNOSTIC SIGNIFICANCE OF HALLUCINATIONS

Compared with the rich phenomenological data that we have on hallucinations, its diagnostic significance is limited.

Hallucination is considered as a core symptom of psychosis by both ICD-10 and DSM-IV.

Auditory hallucinations of thought echo, discussing type in 3rd person and running commentary type (all form part of Schneider's first rank symptoms) form the basis of diagnosing schizophrenia according to ICD-10.

Cenesthetic hallucinations can be diagnostic of a special variety of rare schizophrenia.

Alcohol-related hallucinations can phenomenologically differentiate delirium tremens from alcoholic hallucinosis, but it is very difficult to delineate the latter from schizophrenia.

Auditory hallucinations are most common in all groups except organic brain syndromes, where visual hallucinations predominate.

In spite of the above-mentioned facts, a patient presenting with hallucinations as one of his symptoms needs complete psychiatric and neurological diagnostic evaluations to reach at the correct diagnosis.

Clinically, eliciting hallucinations and analyzing it in detail may be of prognostic and academic importance but, for diagnosis, one must get a holistic account of the patient.

Subclinical hallucination in non-psychotic children and adolescents

Some children or adolescents may report of subclinical hallucination or delusion, yet not fulfill the criteria for specific psychotic disorders [Table 2]. They are not severe or frequent enough to warrant clinical diagnosis of psychotic disorder. They range from 2 to 30% in the clinical groups, including children with conduct and emotional disorders and borderline personality. Three hypotheses in the current literature propose that these symptoms are:

Table 2

Mean rates of hallucination in the general population studies

Part of the dissociative process of PTSD and other abuse-related disorders.

Part of the schizotypal thought process.

Part of depressive symptomatology.

The relationship between childhood trauma and auditory hallucination is not limited to subjects with dissociative disorders, but is also found in the general population and in schizophrenic patients. Kessler[9] screened 341 first-admission psychotic patients and reported that 18 (5.3%) had a history of isolated early childhood hallucination lasting for various durations without other features of psychosis. He suggested that isolated early childhood hallucination may confer increased risk for adult psychosis. It is, however, unclear as to what percent of cases of isolated early childhood hallucination develops into major psychosis later in life.

Hallucinations in non-morbid conditions

Hallucinations in the general population are associated with victimization experiences, average and below average IQ and female sex. A multitude of circumstances can trigger hallucinations in normal persons (as well as clinical populations). These include deprivation (food, sensory, sleep), fatigue, during going into or waking up from sleep, sleep-related states, life-threatening states, bereavement, grief reaction, prolonged perceptual isolation, sexual abuse, religious ritual activities and trance states. Subjects may report hallucinations in conditions of increased external stimulation (e.g., when in a crowd), decreased external stimulation (e.g., when alone at night) or when there is a particular, usually repetitive, background noise (e.g., being close to fans, washing machines). It is common for people (especially older people) to see, hear or feel the presence of the deceased person during bereavement.

TREATMENT OF HALLUCINATIONS

Pharmacological treatment

Hallucination as part of functional or organic psychosis responds best to antipsychotics. All antipsychotics are effective, the newer antipsychotics having an edge over the traditional antipsychotics. General guidelines for pharmacotherapy of psychosis apply for hallucination as well. Twenty-five to 30% of the auditory hallucinations in schizophrenia are refractory to traditional antipsychotic drugs. Even with the advent of newer antipsychotics, a significant minority of patients continue to hallucinate.

Transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS), in particular repetitive TMS (rTMS), has been proposed as a treatment for hallucinations in schizophrenia. Slow (1Hz) rTMS is usually used in the treatment of hallucinations because it reduces brain excitability in contrast to fast rTMS (>5 Hz used in depression treatment), which enhances brain excitability. Studies clearly establishing the efficacy of rTMS for the treatment of hallucinations are lacking. A recent metaanalysis concluded that low-frequency rTMS over the left temporoparietal cortex has a moderate effect size for the treatment of medication-resistant Auditory Hallucinations (AH).[34]

Coping strategies

Coping is defined as constantly changing cognitive and behavioral efforts to change particular external and/or internal demands that are appraised as taxing or exceeding the resources of the person. Self-initiated self-coping is common in psychosis, indicating that individuals who feel overwhelmed by their psychotic experiences mobilize coping defenses. The coping strategies identified in a few studies are summarized in Table 3.

Table 3

Coping strategies adopted by psychotic patients with hallucinations

Psychoeducation

For patients, caregivers and their associates, psychoeducation is a valuable tool for determining what is wrong with the patient and how the condition may have developed. This is especially true for a stigmatizing illness such as schizophrenia and for stigmatizing experiences such as hallucinations. Indeed, a majority of people perceive those who “hear voices” as being violent and unstable, and believe that they should be locked away.[40] The distress related to hallucinations is crucial and causes a number of problems that need to be dealt with. On an individual level, distress associated with hallucinations is alleviated by medications and psychotherapy. However, distress associated with hallucinations may also be decreased on a societal level. That is, if attitudes in the general population concerning hallucinations were less negative and damaging, then this would make it much easier for those suffering from hallucinations to properly manage their experiences. Therefore, education campaigns concerning psychotic experiences geared toward the general public, schools and primary health service are also an important intervention strategy. Brief educational courses in mental illness reduce stigmatizing attitudes among a wide variety of participants.[41]

Cognitive behavior therapy

The aims of Cognitive behavior therapy (CBT) for psychotic patients are to reduce the distress and disability caused by psychotic symptoms, to reduce emotional disturbances and to help the person to arrive at an understanding of psychosis, to promote the active participation of the individual in the regulation of risk of relapse and social disability. Garety et al,[42] conceptualized CBT as a series of six stages: (1) building and maintaining a therapeutic relationship, (2) using cognitive-behavior coping strategies, (3) developing a new understanding of the experience of psychosis, (4) addressing delusions and hallucinations, (5) addressing negative self-evaluations, anxiety and depression and (6) managing the risk of relapse and social disability.

An ABC analysis of voices

According to this formulation, a voice is seen as an activating event (A) to which the individual gives a meaning (B) and experiences the associated emotional and behavioral reactions (C). This, the distress and coping behavior, are consequences not of the hallucination itself but of the individual's belief about hallucination. Table 4 gives two examples of ABC analysis of auditory hallucinations, one for a voice believed to be benevolent and one malevolent.

Table 4

ABC analysis of auditory hallucinations

Evaluation of CBT

Studies suggest that CBT is a modestly effective treatment scheme for positive psychotic symptoms, although there have been negative findings in well-conducted studies. However, few studies have specifically examined the positive effect of CBT on hallucinations, although Valmaggia et al.[43] observed that it may alleviate some features of hallucinations. One general limit of CBT is that it does not deal with the hallucinations themselves but deals exclusively with reactions (e.g., distress) to the experiences. Furthermore, CBT does not improve patients’ depression, negative symptoms or social functioning and, although, CBT is more effective than routine care, the superiority of CBT is less evident when it is compared with other therapies that use equivalent amounts of one-to-one therapist attention. Lynch et al.[44] analyzed pooled data from published trials of CBT in schizophrenia, major depression and bipolar disorder that used controls for non-specific effects of intervention. Trials of effectiveness against relapse were also pooled, including those that compared CBT with treatment as usual. Blinding was examined as a moderating factor. They concluded that CBT is no better than non-specific control interventions in the treatment of schizophrenia and that it does not reduce the relapse rates. CBT was effective in reducing symptoms in major depression, although the effect size was small, and in reducing relapse. CBT was ineffective in reducing relapse in bipolar disorder.

Hallucination-focused integrative treatment

Hallucination-focused integrative treatment (HIT) uses multiple modalities to maximize control of persistent auditory hallucinations. It integrates a number of different types of treatment strategies (CBT, supportive psychotherapy, psychoeducation, coping training, mobile crisis intervention and antipsychotic medication). The intervention uses 20 one-hour sessions over 9–12 months. HIT is different from most CBT programmes in that both patient and relatives receive cognitive interventions and coping training. Studies suggest that HIT is effective for chronic schizophrenia patients and for psychotic adolescents with auditory hallucinations. Also, these positive effects last as long as 9–18 months after treatment.[45]

Methodological difficulties in the psychological treatment of auditory hallucination

Auditory hallucinations are subjective experiences that are difficult to measure objectively. The advent of effective pharmacological treatment might have hampered research on various psychological treatments of auditory hallucination, which has prevented the characterization of any putative good response group. There is insufficient evidence to favor any particular psychological treatment over any other. All the above techniques show a benefit in some patients. This suggests that rather than abandoning psychological therapies, treatment should be individually tailored and used as an adjunct to pharmacotherapy.

CONCLUSION

Hallucination is a fundamental symptom in psychiatry. Two hundred years of research into this phenomenon has not yet answered the following questions:

Whether hallucinations are pathognomic of psychosis or not?

Whether the presence of hallucinations (as such or in different modalities and forms) can include or exclude certain diagnoses or not?

What is the neural substrate of hallucination?

These questions are very basic to the understanding of mental diseases and more research in both the phenomenological and the theoretical areas is necessary to unfathom the secret.

Conventionally, hallucinations are treated as psychotic features. However, there is ample evidence to support hallucination in non-psychotic conditions. The mechanism and nosological status of these conditions are not yet clear. Assessing the cultural background in the evaluation of hallucination is important as the concept of reality varies across cultures and there is a possibility of culturally sanctioned hallucination. Apart from effective pharmacological treatment, a greater awareness is needed regarding the psychological treatment of hallucination, which can help us deal with refractory hallucinations.