DeVylder et al. 2014(Yung et al., 2006 Sample source: Collaborative Psychiatric Epidemiology Surveys (n = 10541). Comparison/control group: Survey respondents who did not report PEs. PEs: WHO CIDI for previous 12 months. Outcomes: Seven questions on use of healthcare in lifetime and the last 12 months. Survey‐weighted regressions with adjustments for sociodemographic covariates and concurrent psychopathology, together with corrections for multiple comparisons. Lifetime (OR 2.2, 95%CI 1.6, 3) and previous 12 months (OR 2.3, 95%CI 1.4, 3.7) care use were associated with PEs after adjustment for current affective, anxiety and substance misuse problems. 8 stars. Large, representative, random sample with validated exposure measures, and regression adjustment for co‐morbid psychopathology and sociodemographic variables. Self‐reported service use.

Gale et al. 2011(Rothstein et al., 2006 Sample source: Representative survey of New Zealand adults (n = 7435). Comparison/control group: Survey respondents who did not report PEs. PEs: CIDI v.3 Outcomes: Mental health service use was assessed using the CIDI. Survey weighted latent class analyses were used to arrive at underlying sub‐groups of sampled subjects, defined by variables including PEs, use of different health services. The use of hospital services, specialist mental health services in general, and any service, increased with the number of PEs. For binary latent classes, psychotic class members had a prevalence of specialist mental health service use of 68.9% (95%CI 49.8, 88.1), compared to 15.3% (95%CI 14.2, 16.4) in the normal group. 6 stars. Large, representative sample with good response rate. Non‐responders were not described and responders were not compared to general population. Validated measure of PEs. Self reported mental health service use. No adjustments were made for comorbid psychopathology.

Smeets et al. 2013(Daalman et al., 2016 Sample source: Dutch household survey, NEMESIS‐1 (n = 7075) Comparison/control group: Survey participants who did not report PEs. PEs: CIDI v.1.1 Outcomes: Respondents were asked whether they had ever having sought care from any mental health institution described in G Section of the CIDI. Data analysis included logistic regression of accessing mental health care against PE status. Models were not adjusted for comorbid psychopathology. Having only hallucinations (OR 2.6, 95%CI 2.1, 3.2), only delusions (OR 3.1, 95%CI 2.7, 3.7), and both hallucinations and delusions (OR 7.5, 95%CI 5.9, 9.6) were strongly associated with accessing mental health care in the lifetime. 7 stars. Large, representative sample, with adequate response and comparability between responders and non‐responders. Validated measurement tool for PEs. Self‐reported mental health service use. No adjustments were made for comorbid psychopathology.

Van Nierop et al. 2011, (Barragán et al., 2016 Sample source: Dutch household survey, NEMESIS‐2 (n = 6646) performed 1996–1999. Comparison/control group: NEMESIS‐2 respondents without PEs. PEs: CIDI v.3 Outcomes: Respondents were asked for reports of accessing mental health care in the context of any psychopathology (help from psychiatrists/ psychologists for any psychiatric problem including drug or alcohol problems) and accessing care specifically for PEs. Analysis employed multinomial logistic regression and linear regression. No adjustments for comorbid psychopathology were made. Compared to controls, people with false positive psychotic symptoms (i.e. with symptoms but not psychotic disorder) were nearly twice as likely to report accessing mental health care (RR 2.02, 95%CI 1.43, 2.87). 7 stars. Large, representative sample with adequate response; comparability described between responders and non‐responders. Validated measurement tool for measurement of PEs. Self reported mental health service use. No adjustments for comorbid psychopathology.

Armando et al. 2012(Fusar‐Poli et al., 2014 Sample source: Non‐random/purposive sample of 997 college students. Comparison/control group: Survey respondents who did not report PEs. PEs: CAPE Outcomes: Subjects were asked to report whether they had need to consult a psychiatrist/psychologist in the past year. The Beck's Depression Inventory(BDI) total score was used to adjust for depression‐ ANCOVA used to assess association between accessing mental health care and factor scores for PEs, and for Beck's Anxiety Inventory and General Health Questionnaire‐12. This study compared people accessing mental health care with non‐help seeking students on various continuous measures of different PEs and anxiety and depression/general functioning. For PEs, only important differences were found for persecutory ideation but not for perceptual abnormalities, bizarre experiences, and magical thinking. 6 stars. Study population sufficiently large, somewhat representative, but gathered by non‐random sampling. No description of non‐response or comparison of responders with non‐responders. Validated measurement tool for ascertainment of PEs. No control applied for comorbid psychopathology.

Daalman et al. 2016(DerSimonian & Laird, 1986), Utrecht, Netherlands, Mixed. Sample source: 103 subjects with auditory/visual hallucinations (at least once per month, for at least one year) and 60 matched controls without Axis I or II disorders. Comparison/control group: 60 matched controls without hallucinations, or Axis I or II disorders. PEs: Launay and Slade Hallucination Scale. Outcomes: Persistence of auditory/visual hallucinations and need for mental healthcare. Restricted one of the regression models to people without remitted depression at baseline. OR for total distress from auditory/visual hallucinations: 2.08 (1.107, 3.9), and 2.08 (1.002, 4.322) when depression at baseline was removed. 39.5% of people with auditory/visual hallucinations had need for mental healthcare at five year follow up, compared to 12.2% in the control group. 5 stars. Cases not clearly consecutive or representative of people with PEs. Community controls were selected without disorder. Restricted one of the regression models to people without depression. Cases and controls were matched, but further details on matching criteria were not reported. Mental health service use ascertained by structured interview, not blinded to hypothesis or case control status. The same method of ascertainment of service use was employed for both cases and controls. The same proportion of non‐response quoted for both groups. PEs were ascertained by self‐report, with the same tool administered to cases and to controls.

Kobayashi et al. 2011(Smeets et al., 2013 Sample source:731 general psychiatric outpatients aged 16–30, 748 students. 2006–2008. Comparison/control group: 748 students from two universities and two high schools. PEs: PRIME tool, a self‐report tool for screening of prodromal symptoms. Outcomes: Use of mental health care was distinguished by case–control status. Cases were defined as using mental health care because they were psychiatric outpatients. Investigators carried out regression adjustment for score on the Zung Self‐Rating Depression Scale (ZSRDS). There was no association between different PE items and utilization of mental health care after adjusting for depression. Researchers did not report adjusted associations between case–control status and the total score for PEs. 9 stars. Adequate case definition for mental health service use, and cases were gathered consecutively. Controls were broadly representative, but were not definitively free of service use for mental health problems. A subgroup of the participants was matched on age. One set of logistic regressions for association between individual PE items and case‐control status models was adjusted for depression score. Used a self‐report screen for PEs, and employed the same method in cases as controls. There were similar non‐participation rates in cases and controls.

Barragan et al. (Egger et al., 1997 Sample source: Collaborative Psychiatric Epidemiology Survey, n = 11,937 Comparison/control group: Subjects without PEs formed the comparison group. PEs: WMH‐CIDI Outcomes: Respondents were asked: “Have you ever in your lifetime been admitted for an overnight stay in a hospital or other facility to receive help for problems with your emotions, nerves, mental health, or your use of alcohol or drugs?” and “Which of the following types of professionals did you ever see about problems with your emotions or nerves or your use of alcohol or drugs?” Service providers were grouped into the following: informal provider (ministers, priests, spiritualist or religious advisor, herbalists, or any other healer),mental health provider (psychiatrist, psychologist, social worker, counselor, or any other mental health professional), and medical provider (general practitioner, medical doctor, nurse, occupational therapist, or any other medical professional). No adjustment was made for concurrent psychopathology. Association between lifetime self‐reported psychotic symptoms and use of services for mental health problems‐ OR: 2.04 (95%CI: 1.26, 3.32) for any lifetime psychotic symptom on accessing any informal/mental health provider, 2.95 (95%CI: 2.82, 4.79) for hospitalization. 6 stars. Large and representative sample; no description of response proportion or characteristics of non‐responders, or similarities between responders and general population. Validated measurement tool for PEs. There was no adjustment of effect for depression/other concurrent psychopathology.

Murphy et al. 2010 (Gale et al., 2011), England, Mixed. Sample source: APMS 2007(n = 7266). Comparison/control group: APMS respondents without psychotic symptoms. PEs: Psychosis Screening Questionnaire. Outcomes: Using mental health care in the previous year was assessed by self‐report, characterised by seeing the GP for emotional problems, seeing the GP for physical problems, and seeking counselling therapy. Adjusted for sociodemographic barriers to referral and the presence of any neurotic disorder. Only paranoia was significantly associated with accessing counselling/therapy after all adjustments were made (OR = 2.92 (1.54, 5.34), with mania, thought control, strange experiences and hallucinations proving non‐significant. 3 and 1 psychotic symptom, but not 2, were associated with counselling/therapy access in the previous year (one symptom OR = 1.74 (1.02, 1.95); two symptoms OR = 2.69 (1.40, 5.15); three symptoms OR = 3.32 (1.90, 5.83)). 9 stars. Large representative, random sample. Comparability was reported between responders and non‐responders. Validated measurement tool for PEs. Controlled for sociodemographic and psychopathological correlates of mental health service use. Associations were reported by different levels of service use.

Saha et al. 2013 (Olfson et al., 2002 Sample source: 8773 general household dwelling adults aged 18–65. Carried out in 2007 Observational survey design(cross‐sectional). Comparison/control group: The comparison group was survey respondents without delusion‐like experiences. PEs: Delusion‐like experiences assessed using the Composite International Diagnostic Interview (CIDI). Outcomes: Lifetime use of GP, psychologist, psychiatrist or any other practitioner for mental health reasons. Lifetime psychiatric admission. Lifetime use of medication for MH. Use of vitamins/herbal remedies for mental health reasons. Study adjusted for age, gender, and then age, gender and comprehensive social demographics. Did not adjust for psychopathology, but restricted sample to people without CIDI comorbidity. ORs from final model (age, gender etc. adjusted, restricted to people without comorbid disorders) were as follows: seeing GP: 1.88 (1.2, 2.93); any psychiatrist: 0.93 (0.42, 2.07); any psychologist: 1.89 (1.04, 3.44); any practitioner: 1.65 (1.17, 2.32); lifetime admission‐ no results because of low power; lifetime prescription medication use: 1.86 (1.09, 3.16); any vitamin herbal use in the last 2 weeks: 1.32 (0.79, 2.22). 8 stars. Large random sample, with comparability between responders and non‐responders discussed, and an adequate response proportion. Validated measurement tool for the ascertainment of PEs. Statistical control for sociodemographic confounders, design control for psychopathology (restricting a sub‐analysis to people without comorbidity). Unclear if mental health service use assessment was blinded.

Nishida et al. (van Nierop et al., 2011 Sample source: Cross‐sectional survey of 4894 students in the Mie prefecture, in grades 7,8 and 9 (ages 12,13, and 14). Carried out in July 2006. Comparison/control group: People without PEs on the DISC‐C. PEs: Psychotic‐like experiences identified using the Diagnostic Interview Schedule for Children (DISC‐C) Outcomes: Dichotomous item on current contact with medical services The odds ratio for the association between psychotic‐like experiences and contact with medical care was adjusted for GHQ score. The crude association between reporting any psychotic‐like experience and being in contact with medical services currently was 1.72 (95%CI: 1.49, 1.98). This was attenuated upon adjustment for score on the GHQ, giving an adjusted estimate of 1.45 (95%CI: 1.23, 1.7). 7 stars. Large survey with adjustments for concurrent psychopathological symptoms, and a validated tool for the measurement of psychotic‐like experiences. No description of non‐responders, and non‐random sampling.

Olfson et al. (Murphy et al., 2010 Sample source: Non‐representative survey of primary care patients at a general medicine practice in Manhattan, New York. Comparison/control group: People who did not report PEs. PEs: Psychotic symptoms were assessed using the Mini International Neuropsychiatric Interview (MINI). Outcomes: Respondents were asked a series of questions relating to the receipt of care for an emotional or mental health problem. Reports chi‐squared statistics and p‐values for the association between psychotic symptoms and psychiatric hospitalization, lifetime and past‐month mental health visits, and lifetime and past‐month use of psychotropic medication. Used linear and logistic regression to adjust for sociodemographic variables and concurrent DSM disorders. Logistic regressions controlling for various covariates were used to model associations between psychotic symptoms and DSM‐IV disorders, substance use disorders, suicidal ideation, and psychiatric hospitalizations. Associations were found between psychotic symptoms and all markers of mental health service use (all p‐values from chi‐squared = <0.0001). 7 stars. Large sample with non‐responders described. Validated measure of psychotic symptoms and measures service use by self‐report.