Childhood Trauma Hikes Adult Psychosis Risk

Childhood and adolescent trauma can cause psychotic experiences in young adulthood, new research shows.

Investigators longitudinally studied close to 4500 youngsters between ages 0 to 17 years to assess whether trauma exposure in early childhood, middle childhood, or adolescence was associated with psychotic experiences at age 18 years.

They found that exposure to any trauma up to age 17 years was associated with highly increased odds of later psychotic experiences, with exposure to multiple trauma types and at multiple age periods leading to greater risk.

"The study found that between 25% and 60% of the young people who reported psychotic experiences — 5% of the sample — would not have developed these if they had not been exposed to trauma such as bullying, domestic violence, or emotional neglect as a child," lead author Jazz Croft, MSc, a doctoral candidate at the Centre for Academic Mental Health, School of Population Health, University of Bristol, UK, told Medscape Medical News.

"This study offers the strongest observational data to date to support that trauma has a causal relationship with psychotic experiences in adulthood and that this relationship isn't confounding for genetic risk of mental health disorders or socioeconomic status," she said.

The study was published online November 21 in JAMA Psychiatry.

Effect of Trauma Types

Although previous research suggests exposure to childhood trauma increases psychosis risk, few studies have examined whether different types of trauma may differentially affect the risk, or whether there is a "sensitive or critical period of risk," the authors write.

"As around 5% of the population have psychotic experiences at some point in their lives, and these often lead to further mental health issues, it is important that we understand more about the role trauma has in increasing this risk," Croft said.

"I wanted to look at traumatic experiences during childhood in a large cohort study because it allowed us to answer questions about the timing and type of trauma that previous studies have not been able to examine comprehensively," she said.

To investigate the question, the researchers used data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective cohort sample of children born to women who resided in the former Avon Health Authority area in England and had expected delivery dates between April 1, 1991 and December 31, 1992.

Psychotic experiences were assessed using the psychosis-like symptoms semi-structured interview (PLIKSi), which was administered at age 12 years, and again at 18 years.

The scale is used to assess the presence of 12 psychotic experiences, including hallucinations, delusions, and experiences of thought interference.

The assessment conducted at age 18 years rated psychotic experiences that occurred after age 12 years, which was the outcome used for primary analyses.

The assessment at age 18 years also rated psychotic experiences that occurred during the previous 12 months, which was the outcome used for sensitivity analyses.

Study Design

Participants or their parents completed questionnaires that included 121 variables about traumatic events.

Trauma types included physical abuse, sexual abuse, emotional abuse, emotional neglect, domestic violence, or bullying.

Data from 48 of 49 assessments were reviewed contemporaneously. However, data regarding sexual abuse, physical abuse, and emotional neglect were also supplemented at age 22 years.

The variables derived represented exposure to any trauma type between ages 0 and 17 years and exposure to any trauma type within a distinct age period (early childhood, 0-4.9 years; middle childhood, 5-10.9 years; or adolescence, 11-17 years).

Additional variables included exposure to specific trauma types between ages 0 and 17 years and exposure to specific trauma types within each distinct age period.

Potential confounders, which had been assessed around the time of the participant's birth, included parental information (for example, psychiatric history, genetic risk for schizophrenia, drug use, criminal history, income, smoking during pregnancy, and living conditions).

Participant confounders included sex, ethnicity, genetic risk for different mental disorders, temperament at 6 months, developmental delay at 18 months, and IQ at age 8 years.

Dose-R esponse Relationship

The complete-case analytic sample consisted of 3758 participants.

Researchers also calculated an imputed sample of those who had completed the PLIKSi at age 18 years (56.5% female; mean [SD] age, 17.8 [0.38] years).

Of these, 9.3% were rated at their age 18-year assessment as having had "suspected" or "definite" psychotic experiences.

Of the imputed sample, 64.5% reported exposure to any trauma between the ages of 0 and 17 years, with 22.4%, 43.7%, and 38.6% reporting exposure during early childhood, middle childhood, and adolescence, respectively.

The adjusted model included sex, parental drug use, living condition, income, and maternal education.

In general, those who were exposed to different types of trauma were more likely to report "more adverse family characteristics."

In particular, a high percentage of females reported trauma exposure (56.3% physical abuse, 59.2% emotional abuse, 49.0% bullying, 87.1% sexual abuse, 42.7% domestic violence, and 50.0% emotional neglect).

Of those participants in the imputed sample who had psychotic experiences at age 18 years, 83.8% reported exposure to trauma, compared with 62.6% without psychotic experiences.

The researchers found increased odds of psychotic experiences at age 18 years (OR, 3.13; 95% CI, 2.32 - 4.22; P < .001) to be associated with exposure to any trauma up to age 17 years.

Adjusting for confounders attenuated the OR, but only by approximately 10% (adjusted OR, 2.91; 95% CI, 2.15 - 3.93; P < .001).

The effect size was increased with exposure to a greater number of trauma types between ages 0 to 17 years, with those reporting three or more types of trauma exposure showing a 4.7-fold increase in odds of psychotic experiences (95% CI, 3.40 - 6.59; P < .001).

A large dose–response relationship was found, wherein exposure to trauma during all three age periods was associated with a higher risk of developing psychotic experiences than exposure within only one or two age periods.

Candidate Mechanisms

All trauma types between ages 0 and 17 years were associated with increased odds of psychotic experiences (adjusted ORs, 1.69-2.50; all P < .001), with a "substantial" overlap between specific trauma types and psychotic experiences.

In the multivariable model that adjusted for all trauma types, a strong association with psychotic experiences persisted for physical abuse, sexual abuse, bullying, and emotional neglect (adjusted OR, 2.24; 95% CI, 1.75 - 2.87; 2.04 [1.42 - 2.91]; 1.80 [1.43 - 2.26]; and 2.33 [1.70 - 3.21], respectively).

Although an association was found between exposure to trauma during any of the age groups as well as increased odds of psychotic experience, after adjusting for confounding, there was a 20% versus 10% attenuation rate for trauma exposure during early childhood versus adolescence, respectively.

The effect sizes were greater for exposure to trauma that was more proximal to the outcome, although the confidence intervals overlapped with more distal exposure, the authors note.

"Our findings demonstrate that the effects of trauma increase the risk of psychotic experiences throughout childhood and adolescence to a similar extent," said Croft.

Moreover, "we found the relationship to be consistent, regardless of socioeconomic status or genetic risk of mental health difficulties, timing — early childhood, mid-childhood, or adulthood — or type, and that the risk of psychotic experiences was increased based on how frequently exposure to trauma was reported."

She suggested potential mediators of this relationship, including "candidate biological mechanisms, such as dysregulated dopamine in response to chronic stress and, potentially related, cognitive factors such as increased attention to threat or alterations in perception."

Screening Critical

Commenting on the study for Medscape Medical News, Yael Dvir, MD, vice chair and director, child and adolescent psychiatry, and associate professor of psychiatry and pediatrics, University of Massachusetts Medical School, Worcester, who was not involved with the study, emphasized that "it is important to screen for trauma in young people who develop psychosis [and] it is important to screen for psychosis in youth who experienced trauma."

This is particularly important because "there is emerging evidence that trauma-informed psychotherapeutic approaches, such as trauma-focused cognitive behavioral therapy, are beneficial in those with psychotic illnesses and trauma," she noted.

Moreover, she added, there are "societal and public health implications — if trauma was removed from the population, the prevalence of costly mental illnesses, such as psychotic illnesses, would decrease significantly, [which is] critical for designing interventions and for advocacy efforts."

Croft agreed.

"The findings support that routine screening for psychotic experiences in children or young people exposed to trauma, particularly those exposed to frequent occurrences, should be considered as a way of preventing later mental health problems."

She added, "Understanding how trauma leads to psychotic experiences could lead to the development of more novel treatment for psychosis."

The study was funded by the UK Medical Research Council (MRC). Individual investigators have reported receiving grants from the DJ Noble Foundation, Biomedical Research Centre at the University Hospitals Bristol NHS Foundation Trust and University of Bristol funded by the National Institute for Health Research; and European Research Council Consolidator Award (iHEAR). The MRC, Wellcome Trust, and University of Bristol provide support for ALSPAC. Croft and colleagues, as well as Dvir, have reported no relevant financial relationships.

JAMA Psychiatry. Published online November 21, 2018. Full text

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