Hallucinations are relatively common in children. Two-thirds of children ages nine to 11 have had at least one psychotic-like experience, including hallucinations.

Studies of large pediatric samples document an eight percent hallucination prevalence rate in children (McGee R et al, JAACAP 2000;39(1):12-13). The vast majority of hallucinations in the general pediatric population are transient and resolve spontaneously. In approximately 50% to 95% of cases, hallucinations discontinue after a few weeks or months (Rubio JM et al, Schizophr Res 2012;138(2-3):249-254).

Hallucinations can be scary for parents and other caregivers, but they don’t usually signal major psychopathology and are mostly associated with anxiety and stressful events. In this article, we’ll explore some of the causes of psychotic and non-psychotic hallucinations in children and adolescents and appropriate interventions for them.

What Exactly is a Hallucination?

Sir Thomas Browne, the 17th century physician, coined the term hallucination in 1646, deriving it from the Latin alucinari meaning “to wander in the mind.” DSM-IV defines a hallucination “as a sensory perception, which has the compelling sense of reality of a true perception, but occurs without external stimulation of the relevant sensory organ.”

Hallucinations are distortions in sensory perception in any or all of the five human senses. The most common hallucinations are auditory and visual, but olfactory, gustatory (taste), tactile, proprioceptive, and somatic also occur. Hallucinations may be mood-congruent or incongruent.

“True” hallucinations must be distinguished from perceptual distortions such as illusions or vivid imaginings, and other phenomena such as obsessions, compulsions, dissociative phenomena, pseudohallucinations, and borderline syndrome of childhood (Lewis M, Child Adolesc Psychiatr Clin North Am 1994;3:31-43). In addition, hallucinations may be feigned by children and adolescents, often to get themselves out of situations with the law, their parents, peers, and others in authority (Resnick PJ. In: Rogers R, ed. Clinical Assessment of Malingering and Deception. 2nd ed. New York: Guilford Press;1997:p 47-67).

An hallucination is meaningful only after a child has learned to distinguish between his/her internal world and external reality. There is disagreement as to the age when this distinction can be made, but it is thought that a normal child of average intelligence is fully able to distinguish between fantasy and reality by the age of three (Piaget J. The child’s construction of reality. London: Routledge and Kegan;1995).

Imaginary companions, sometimes described as “hallucination-like phenomena,” differ from hallucinations in that they can often be evoked by the child at will (in contrast with the involuntary nature of hallucinations), and may typically function as playing partners associated with positive emotions. However, “noncompliant imaginary companions” exist, and are resistant to the host child’s control (Taylor MA. Imaginary Companions and the Children Who Create Them. UK: Oxford University Press;1999).

Other related phenomena observed during the developmental period include sleep-related hallucinations. Hypnagogic hallucinations, occurring immediately before falling asleep, and hypnopompic hallucinations, occurring during the transition from sleep to wakefulness, are reported in 25% and 18% of the general population, respectively, but decline with age into adulthood. These may be part of a disabling childhood sleep disorder such as narcolepsy with cataplexy (Dauvilliers Y et al, Lancet 2007;369(9560):499-511).

Pseudohallucinations are mental images which, although clear and vivid, lack the substantiality of perceptions. They are seen in full consciousness, known to be not real perceptions, are not located in objective space, but in subjective space, and are dependent on the individual’s insight. They may be experienced by hysterical or attention-seeking personalities.

Psychiatric Causes and Comorbidities

Many non-psychotic hallucinations are associated with periods of anxiety and stress, and disappear when the stressful situation is resolved (Mertin P & Hartwig S, Child Adolesc Ment Health 2004;9(1):9-14).

Illusions are misperceptions or misinterpretations of real external stimuli and may occur in delirium, depression with delusions of guilt, and/or be self-referential. These may manifest as fantastic illusions in which a child or adolescent describes extraordinary modifications of his environment (eg, he looks in a mirror and instead of seeing his own head, sees that of a pig); or pareidolia—illusions that occur without the patient making any effort, which may be due to excessive fantasy thinking and a vivid visual imagery.

Several studies have demonstrated that experiencing childhood trauma is a risk factor for psychosis and hallucinations. A positive association has been found for sexual abuse, physical abuse, emotional abuse, bullying, or neglect, but not parental death (Varese F et al, Schizophr Bull 2012;38:661-671). A subsequent study confirmed that those with high sexual abuse scores were two to four times more likely to develop adult psychosis (Thompson AD et al, Schizophr Bull 2014;40(3):697-706).

Mood disorders can often present with accompanying psychotic features, including hallucinations (Edelsohn GA, Am JPsychiatry 2006;l63(5):781-785). Research in clinical populations demonstrated that 11- to 15-year-old patients who reported psychotic experiences had, on average, three diagnosable DSM-IV, Axis I disorders. In these cases, psychotic symptoms predict more severe psycho-pathology (Kelleher et al, Br J Psychiatry 2012;201(l):26-32).

There is a significant relationship between psychotic hallucinations and suicidal behavior. Adolescents with a diagnosis of major depression disorder (MDD) who report psychotic experiences had a 14-fold increase in suicide plans or attempts compared to adolescents with the same diagnosis who did not report psychotic experiences (Kelleher I et al, Arch Gen Psychiatry 2012;69(12):1277- 1283).

Non-psychotic children who hallucinate may have diagnoses of ADHD (22%), MDD, (34%), or disruptive behavior disorders (21%) (Edelsohn GA et al, Ann N Y Acad Sci 2003;1008:261-264).

What About Schizophrenia in Childhood and Adolescence?

Childhood-onset schizophrenia is extremely rare, and the majority of children experiencing hallucinations do not progress to that level of psychiatric disturbance. The likelihood of schizophrenia occurring before 13 years of age is one in 30,000 (Jardri R et al, Schizophr Bull 2014;40(suppl 4):S221-S232). Schizophrenia can be reliably diagnosed in children and it is neurobiologically, diagnostically, and physiologically continuous with the adult disorder.

Hallucinations in Children, Adolescents: Psychiatric, Medical Causes, Assessments and Treatment