Grownups with imaginary friends may be more prone to hearing voices

As a child, did you have an imaginary friend? Studies have found that up to two thirds of seven-year-olds play with invisible friends, but it turns out a surprisingly large number of adults also have fantasy companions.

In the biggest online survey of its kind, conducted by psychologists at the University of Durham in the UK, 7.5% of people claimed to have had one as an adult. The same people were also more likely to report experiencing auditory vocal hallucinations (AVHs) or “hearing voices” than those who had never had an imaginary companion. A second, lab-based study conducted by the same psychologists backed up the findings, raising the possibility that the two phenomena – hearing voices and fantasy friends – share the same underlying brain mechanism.

Between a third and two thirds of seven-year-olds have an imaginary companion (IC for short). Psychologists now believe this to be a perfectly healthy part of growing up, but in the past, the apparent similarities between ICs and hearing voices provoked fears among parents that their child might be more likely to develop a mental illness such as psychosis in later life.

The idea there might be a link between having an IC in childhood and mental illness in later life has now been discredited. Unlike imaginary childhood friends, which are either invisible or embodied in a toy or other object, AVHs are usually perceived as internal. They arise spontaneously and are often highly critical and uncooperative, whereas children deliberately create their ICs and generally find them friendly and helpful.

Far from being a sign that something is wrong, on tests of theory of mind (intuiting what others are thinking and feeling), sociability, understanding emotions and constructing complex narratives, children who have an IC tend to perform better than children who don’t. This has led psychologists to theorise that rather than being a quirky aberration, interacting with an IC may reflect the way children gradually internalise external chatter to create the inner “dialogic” or social-like speech that characterises adult thought.

The latest pair of studies, conducted by Charles Fernyhough and his colleagues at the University of Durham, are consistent with this theory. The research, published in Frontiers in Psychology, also provides the first scientific evidence of the existence of ICs in adults. Previously, there were only anecdotal reports of adult ICs.

In the first study, out of 1,472 adults responding to an online survey, 41% said they had an IC in their childhood. Overall, 7.5% said they had interacted with an IC as an adult and this number rose to 13.8% among those who remembered having an IC when they were children.

Respondents with any experience of ICs were also more likely to report hearing voices than those who had never had an imaginary friend, with the highest score on an AVH questionnaire among those who had an IC in both childhood and adulthood. The survey also found that people who reported having more social-like inner speech (characterised by things like different characters and dialogue) appeared to be more prone to AVHs.

A major limitation of this study was that it relied on self-reports. So for the second, lab-based study the psychologists recruited 14 young adults who said they had a history of ICs and 34 with none, then cross-checked these claims with their parents.

In addition to filling out the questionnaires used in the first study, subjects were given a standard test measuring theory of mind, called Reading the Mind in the Eyes. They also took a type of hearing test that involved listening to five-second bursts of white noise that either contained clearly audible speech, no speech at all, or speech played at intermediate volumes. After each, participants reported whether they could hear speech. Previous research has shown that people who are biased towards hearing speech in white noise when none is actually present are more likely to experience AVHs.

This second study confirmed the presence of ICs in adults and its higher prevalence among people who had an imaginary friend when they were growing up. It also backed up the finding that people who have an IC during childhood are more likely to hear AVHs as adults.

In addition, the results were consistent with the idea that having an IC helps in the development of dialogic inner speech. Subjects who had any experience of an IC, as children or adults, reported having more social-like inner speech. Scores on the theory of mind test didn’t differ significantly between any of the groups, however.

The psychologists concede that their second study was too small to draw any firm conclusions about childhood ICs helping to internalise speech, and they caution against assuming that ICs in adulthood are imaginary childhood friends who never went away. A longitudinal study, following particular individuals from childhood into adulthood, will be needed to explore these questions further.

Importantly, the two studies say nothing about possible links between the experience of AVHs in the general population and psychosis. The studies did find that people who interact with imaginary friends are more likely to hear voices, but lots of people who are not suffering from psychosis have this kind of auditory hallucination.

Around 6-7% of the general population report hearing voices at some time, which has led to the proposal that the experience of hearing voices in mentally well people is on a continuum with that in patients with schizophrenia: they might share the same underlying brain mechanism. But a study co-authored by Fernyhough that was published in Schizophrenia Bulletin earlier this year (summarised here), found that while patients who heard voices had a shorter paracingulate sulcus – a brain structure involved in reality monitoring – there was no such difference between mentally well people who heard voices and control subjects who did not.

Rather than being a disadvantage, accomplished fiction writers may harness their ability to create and engage with internal voices to bring their characters to life on the page. Writers often report that it’s as if their characters had minds of their own. By the same token, readers who have an innate tendency to hear and interact with voices in their heads may experience fictional characters in novels as more vivid, autonomous and real, greatly enhancing their reading pleasure.