From phenomenology to neurophysiological understanding of hallucinations in children and adolescents

Abstract

Typically reported as vivid, multisensory experiences which may spontaneously resolve, hallucinations are present at high rates during childhood. The risk of associated psychopathology is a major cause of concern. On the one hand, the risk of developing further delusional ideation has been shown to be reduced by better theory of mind skills. On the other hand, ideas of reference, passivity phenomena, and misidentification syndrome have been shown to increase the risk of self-injury or heteroaggressive behaviors. Cognitive psychology and brain-imaging studies have advanced our knowledge of the mechanisms underlying these early-onset hallucinations. Notably, specific functional impairments have been associated with certain phenomenological characteristics of hallucinations in youths, including intrusiveness and the sense of reality. In this review, we provide an update of associated epidemiological and phenomenological factors (including sociocultural context, social adversity, and genetics, considered in relation to the psychosis continuum hypothesis), cognitive models, and neurophysiological findings concerning hallucinations in children and adolescents. Key issues that have interfered with progress are considered and recommendations for future studies are provided.

Keywords: adolescence; childhood; hallucinations; review.

Fig. 1.

Factors affecting hallucinations in childhood and adolescence. Even if early-onset hallucinations cannot always be totally separated in characteristic profile, trajectory, and outcomes, 2 types of experiences can be distinguished: hallucinations that occur in the context of childhood psychosis and those that do not. Three main categories of factors can then be defined. A first subset of factors influence the occurrence of hallucinatory experiences during childhood (predisposing or protecting factors). Modifying factors (cultural, religious, and spiritual) will affect both the prevalence and the phenomenology of early-onset hallucinations. A third category of factors is associated with persistence of hallucinations during adolescence, and with poorer outcomes. Importantly, based on the extant literature, arrows should be taken to indicate developmental associations rather than causality; in cases where causality might be inferred, causal relations might be unidirectional or bidirectional.