CLINICAL ASPECTS OF HALLUCINATIONS
Schizophrenia
The IPSS estimated that 70% of schizophrenia patients experienced hallucinations. The most common
hallucinations in schizophrenia are auditory, followed by visual. Tactile, olfactory and gustatory are
reported less frequently . Visual hallucinations in schizophrenia have a predominance of denatured
people, parts of bodies, unidentiable 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
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, misidentication, 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 speci c association between hallucinations and
childhood sexual abuse.
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.
a. Hallucinations as a side-effect of medication,
b. Antidepressants such as amitriptyline, imipramine, trazodone and amoxapine can cause
hallucinations,
c. Digoxin can cause formed and unformed visual hallucinations
d. Propranolol can cause visual hallucinations
e. Benztropine and trihexyphenidyl can cause visual hallucinations
f. Hallucinations are reported with cimetidine, clonidine bromocriptine, levodopa, methylphenidate,
antihypertensives, corticosteroids, antineoplastic and antibiotics.
Hallucination in neurological and organic mental disordersFormed 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
hallucination. In the above condition the modality and content of hallucination depends on the area of
the brain involved.reported an incidence of 34% visual hallucinations and 18% auditory hallucinations.
A comprehensive literature review gave a higher gure of 40–75% for any type of hallucination
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
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.
Hallucination 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 endings.
Hallucination 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-dened 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 signicant 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.
DIAGNOSTIC SIGNIFICANCE OF HALLUCINATIONS
Compared with the rich phenomenological data that we have on hallucinations, its diagnostic
signicance is limited.
1. Hallucination is considered as a core symptom of psychosis by both ICD-10 and DSM-IV.
2. Auditory hallucinations of thought echo, discussing type in 3rd person and running commentary
type (all form part of Schneider’s rst rank symptoms) form the basis of diagnosing schizophrenia
according to ICD-10.
3. Cenesthetic hallucinations can be diagnostic of a special variety of rare schizophrenia
4. Alcohol-related hallucinations can phenomenologically differentiate delirium tremens from alcoholic
hallucinosis, but it is very difcult to delineate the latter from schizophrenia
5. 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,
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 specic psychotic disorders . 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:
1. Part of the dissociative process of PTSD and other abuse-related disorders.2. Part of the
schizotypal thought process.3. Part of depressive symptomatology.
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 rst-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.
Hallucination 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 treatmentHallucination 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 ef cacy 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).
Coping strategies
Coping is dened 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 identi ed in a few studies
are summarized in Table 3.
Psychoeducation
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 .
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.
Evaluation of CBTStudies
suggest that CBT is a modestly effective treatment scheme for positive psychotic symptoms, although
there have been negative ndings 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-specic 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-speci c 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.
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 insufcient evidence to favor any particular psychological treatment over any
other. All the above techniques show a bene t in some patients. This suggests that rather than
abandoning psychological therapies, treatment should be individually tailored and used as an adjunct to
pharmacotherapy
