Mental Health Service Use and Psychopharmacological Treatment Following Psychotic Experiences in Preadolescence

This study was a longitudinal register-based follow-up study of the Copenhagen Child Cohort 2000, a birth cohort encompassing 6,090 children from the general population born in 2000 (13). Baseline data for children in our study were obtained between May 2011 and October 2012 (at ages 11–12), and the children were followed up in registers until June 2017 (at ages 16–17). The total study population comprised 1,632 children (27% of the Copenhagen Child Cohort) who participated in face-to-face assessments at ages 11–12. Children who did not participate in the face-to-face assessment were characterized by lower birth weight and gestational age, as well as male sex, and they had younger and less educated mothers, higher probability of having immigrant parents, higher changes in family composition or rates of not living with both parents, and higher rates of parental mental illness. These findings have been described in detail elsewhere (14).

We used Cox proportional hazards regression models to compare outcomes among children with and without psychotic experiences regarding the first date of psychiatric diagnosis in mental health services and the use of psychotropic medications. Individual follow-up started on the date of examination for psychotic experiences, and hazard ratios and adjusted hazard ratios and 95% confidence intervals were calculated. Children who had already been diagnosed with a psychiatric disorder in a mental health setting before examination for psychotic experiences at age 11 or 12 were excluded from the analyses. Children were censored at the date of event (date of first diagnosis or prescription of psychotropics, depending on the analysis), the date of emigration, or the end of follow-up (June 2017). We stratified analyses by meeting criteria for DAWBA-based mental disorders at ages 11–12 and by parental psychiatric diagnosis. Unadjusted results were graphically presented using cumulative hazard plots that were smoothed with Epanechnikov kernel smoothing to ensure that individuals could not be identified in the plots. Further analyses were adjusted for sex, birth and sociodemographic characteristics, and estimated IQ. The proportional-hazards assumptions were tested comparing Cox-predicted curves and Kaplan-Meier observed curves using survival curves and Schoenfeld residuals after model fitting. All analyses were performed with Stata, version 14, with a two-sided significance level of 5%.

The Copenhagen Child Cohort 2000 study was approved by the Danish Data Protection Agency. The local Committee on Health Research Ethics found the study to be non-notifiable. The principles of the Declaration of Helsinki were followed; informed consent was obtained from the participants and their families, and data were anonymized and used for research purposes only.

This study is, to our knowledge, the first prospective study to examine psychotic experiences in children in relation to independently assessed outcomes regarding psychiatric diagnosis from both inpatient and outpatient mental health services, across different categories of psychiatric disorders, as well as the use of psychotropic medications. Children with psychotic experiences at age 11, without a past history of clinical psychiatric disorders, were three times more likely to be diagnosed in psychiatric services or to receive psychotropic medications within 5 years of follow-up compared with children without psychotic experiences. The increased risk of diagnosis and treatment was observed across main groups of psychiatric disorders. Children with both psychotic experiences and a DAWBA-based diagnosis at age 11 were the subgroup most likely to be diagnosed in psychiatric services during the follow-up period. It is noteworthy that a significantly increased risk of later psychiatric disorders was also observed among children with psychotic experiences who did not meet criteria for a DAWBA-based diagnosis at age 11. In addition, parental history of mental disorders appeared to co-contribute to more detrimental outcomes of psychotic experiences.

These findings should be interpreted in light of some strengths as well as limitations of the study design. The study’s strengths include the nearly 100% follow-up rate, as a result of register-based outcomes, and all outcome variables were independent of children’s examinations at ages 11–12. The registers also provided unbiased information on parental history of mental disorders, and we could account for mental disorders among children diagnosed before measurement of psychotic experiences. We had a strong measure of psychotic experiences, because all children were interviewed by trained clinicians at baseline.

Limitations of the study include the lower participation rate of children with perinatal and sociodemographic adversities in the face-to-face examinations of psychotic experiences. However, a previous study demonstrated that attrition was nondifferential regarding exposure to psychotic experiences (14). Additionally, our study relied solely on hospital-based inpatient and outpatient diagnoses. This was partially remedied by supplementing with data on the use of psychotropic medications prescribed by child and adolescent psychiatrists in private practice. Still, children with emotional disorders, such as anxiety, who most often solely receive therapeutic or psychosocial interventions outside psychiatric settings, are not included in the registers that we used. It should also be noted that first-time neurodevelopmental disorders were frequently diagnosed during the follow-up period (ages 11–16), although diagnostic criteria for these disorders require that symptoms be present in early childhood. However, the study instead adds value in reflecting the help-seeking behavior leading to clinical diagnoses in real-life settings, in which the overall good validity of the register diagnoses has been demonstrated (23). Finally, because this study was population based, mental disorders were rare, which required grouping of specific diagnoses. Psychotic disorders in particular were rare up to age 16. Hence, to adhere to ethical guidelines and to ensure that the participants’ anonymity was preserved, we could not assess the specific outcome of psychotic disorders. Because most psychotic disorders in this study cohort will likely be diagnosed in the two decades after the present study’s follow-up period (24), it is likely that future follow-up of the cohort will reveal increased specificity of psychotic experiences in predicting psychotic disorders in adults, in line with previous longitudinal research (8, 12).

Although psychotic experiences predicted clinical diagnoses made in mental health settings and use of psychotropic medications in the 5-year follow-up, psychotic experiences were not associated with diagnosed psychiatric disorders before ages 11–12. Conversely, a previous cross-sectional study of the same cohort found that psychotic experiences were strongly associated with DAWBA-based mental disorders, particularly emotional disorders, at ages 11–12 (4). This finding can be interpreted from the view of psychotic experiences as a general marker of distress (25). Children who had already been diagnosed at an early age, predominantly with neurodevelopmental disorders, likely had been offered psychiatric and psychosocial interventions, which may have alleviated distress.

It is also noteworthy that adjusting for IQ and sociodemographic and perinatal adversities, which are known risk factors for later psychopathology, did not attenuate the estimated risk for later psychiatric disorder following psychotic experiences or a DAWBA-based diagnosis at ages 11–12. This finding can be interpreted in light of evidence from network models of psychopathology (26), suggesting that once psychopathology has its onset, different symptoms reinforce each other in and by themselves (27) and over time cause more severe psychopathology.

Our study adds to the evidence that psychotic experiences in childhood are associated with later psychiatric disorders across the diagnostic spectrum, which according to a recent meta-analysis has not been convincingly shown in previous studies (6). Hence, our findings add to the evidence of psychotic experiences as an overall marker of the severity of general psychopathology (28). In addition, we incidentally found evidence suggesting a lagged effect on later clinical diagnosis in mental health services from only having psychotic experiences compared with only fulfilling criteria for DAWBA-based diagnosis at baseline. This suggests that psychotic experiences in childhood are not only a marker of contemporary distress but may also constitute an underlying vulnerability marker of psychopathology, which in turn opens a window of opportunity for early detection of clinically important psychopathology. However, this finding was not a result of our a priori hypotheses and requires replication.

Using a hard outcome of clinical diagnosis in mental health services, this study demonstrated effects of psychotic experiences in children on subsequent diagnosis in mental health services comparable to findings in adult populations in a recent meta-analysis (10). However, one must keep in mind that the absolute risk is relatively low: less than one in four of individuals with psychotic experiences who were not diagnosed within mental health services before baseline received a psychiatric diagnosis during the 5-year follow-up period. Low positive predictive values were also found in a recent study of adults using a broader psychoticism exposure variable (29). Nevertheless, our finding should be considered in light of the fact that not all individuals in need of psychiatric treatment make contact with tertiary mental health services and that the positive predictive values in our study are expected to increase over later follow-up. Additionally, the children with psychotic experiences in our cohort who did not make contact with mental health services may still benefit from primary nonspecific prevention, such as psychological or psychosocial interventions in school settings or through social services. Importantly, the estimated hazard ratios reported for psychotic experiences alone and DAWBA-based diagnosis were similar, and the conjoined effects of psychotic experiences and meeting criteria for DAWBA-based diagnosis were striking (hazard ratios around 7–10 across models). This further supports the idea that psychotic experiences add to the prediction of future general mental health problems (30) and that these experiences contribute to the identification of children for whom secondary, or even tertiary, prevention is indeed indicated (31). Clinically, our findings support the general direction of preventive and early intervention services to provide transdiagnostic services and treatments (32, 33). Although previous studies have found that psychotic experiences show some degree of specificity for psychotic disorders (12, 34), there is a potential to prevent considerably higher numbers of common mental health outcomes (35).

This study adds to the existing evidence that psychotic experiences should be part of any mental health screening of children and adolescents (3, 4, 30). Even though psychotic experiences usually should not prompt imminent concern about development of a psychotic disorder, they should induce concern for the well-being of the child and lead to examination and identification of potential areas of intervention to reduce overall distress and burden (31). This in turn may ultimately lead to prevention and alleviation of mental health problems, and disorders for some individuals, across the diagnostic spectrum.