The association between delusional-like experiences, and tobacco, alcohol or cannabis use: a nationwide population-based survey

Psychotic-like experiences and problem drinking among adults in Japan

BACKGROUND

Psychotic-like experiences (PLEs) are common in the general population and have been linked to alcohol misuse and abuse. However, much of this research has been undertaken in Western countries. To address this deficit, the current study examined the association between PLEs and problem drinking in the Japanese general population.

METHODS

Data were used from 3717 adults (age 18-89) collected in an online survey in 2023. Information was obtained on PLEs with the PRIME Screen-Revised (PS-R), while problem drinking was assessed with the CAGE questionnaire (where a score of ≥ 2 was used to categorize cases). Logistic regression was used to examine the associations.

RESULTS

Problem drinking was prevalent in the study sample (12.5%). In an analysis that was adjusted for sociodemographic factors, self-rated health, smoking status and depressive symptoms, PLEs were associated with significantly higher odds for problem drinking in the total sample (OR: 1.70, 95%CI: 1.13-2.55). In a sex-stratified analysis PLEs were not linked to problem drinking in men (OR: 1.16, 95%CI 0.68-2.00), whereas women with PLEs had over 2.8 times higher odds for problem drinking (OR: 2.83, 95%CI: 1.54-5.21).

CONCLUSION

PLEs are associated with problem drinking in the Japanese general population and this association is especially pronounced in women. As problem drinking has been linked to a number of detrimental outcomes, future research should examine the potential effects of problem drinking in individuals with PLEs.

Hazardous drinking in young adults with co-occurring PTSD and psychosis symptoms: A network analysis

BACKGROUND

Existing literature suggests the co-occurrence of post-traumatic stress disorder (PTSD) and psychosis among young adults is related to hazardous drinking. However, the influencing mechanisms among these co-occurrences are inconclusive. Thus, this study aimed to investigate the symptomatic associations between PTSD, psychosis, and hazardous drinking.

METHODS

This study included 96,218 young Chinese adults, divided into three groups (PTSD, Psychosis, and co-occurring PTSD-Psychosis). PTSD, psychosis, and hazardous drinking were measured by the ten-item Trauma Screening Questionnaire, the seven-item Psychosis Screener Scale, and the four-item Alcohol Use Disorders Identification Test, respectively. Network analysis was utilized to explore and compare the symptomatic correlation between PTSD, psychosis, and hazardous drinking.

RESULTS

In this study, the most crucial symptom (both central and bridge) was "delusion of control" among the three networks. Hazardous drinking was another main bridge symptom. Compared to the Psychosis group and the co-occurring PTSD-Psychosis group, "Delusion of reference or persecution" to "Grandiose delusion" was the strongest edge in "the network structure of the PTSD group".

LIMITATIONS

The cross-sectional study cannot determine the causal relationship. Applying self-reporting questionnaires may cause inherent bias. Young adult participants limited the generalization of the results to other groups.

CONCLUSIONS

Among the three network structures, delusion of control was the most crucial symptom, and hazardous drinking was another bridge symptom; the edge of delusion of reference or persecution and grandiose delusion was strongest in the PTSD group's network. Efforts should be taken to develop diverse targeted interventions for these core symptoms to relieve PTSD, psychosis, and hazardous drinking in young adults.

Tobacco smoking, second-hand smoking exposure in relation to psychotic-like experiences in adolescents

BACKGROUND

Previous literature supports that tobacco smoking and second-hand smoking (SHS) exposure were strongly associated with poor mental health in the general population. However, there is a lack of empirical data on the relationship between tobacco smoking, SHS exposure and psychotic-like experiences (PLEs). This study conducted a cross-sectional survey to explore PLEs and the associations of PLEs with tobacco smoking and SHS exposure among adolescents in China.

METHODS

A total sample of 67 182 Chinese adolescents were recruited from Guangdong province in China (53.7% boys, mean age = 12.79 years) from December 17 to 26, 2021. All adolescents have completed self-reported questionnaires on demographic characteristics, smoking status, SHS exposure and PLEs.

RESULTS

Within the sample, only 1.2% of participants had an experience of tobacco smoking while approximately three-fifths reported being exposed to SHS. 10.7% of adolescents reported frequent PLEs over the past month. Adolescents who smoked showed a higher prevalence of PLEs than in non-smoking samples. After controlling for confounders, SHS exposure was a robust risk factor for PLEs with or without the effect of tobacco smoking.

DISCUSSION

These findings support the importance of smoke-free legislation, and anti-smoking measures in educational settings directed at both adolescents and their caregiver, which may decrease occurring rates of PLEs among adolescents.

Tobacco use in first-episode psychosis, a multinational EU-GEI study

BACKGROUND

Tobacco is a highly prevalent substance of abuse in patients with psychosis. Previous studies have reported an association between tobacco use and schizophrenia. The aim of this study was to analyze the relationship between tobacco use and first-episode psychosis (FEP), age at onset of psychosis, and specific diagnosis of psychosis.

METHODS

The sample consisted of 1105 FEP patients and 1355 controls from the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. We assessed substance use with the Tobacco and Alcohol Questionnaire and performed a series of regression analyses using case-control status, age of onset of psychosis, and diagnosis as outcomes and tobacco use and frequency of tobacco use as predictors. Analyses were adjusted for sociodemographic characteristics, alcohol, and cannabis use.

RESULTS

After controlling for cannabis use, FEP patients were 2.6 times more likely to use tobacco [p ⩽ 0.001; adjusted odds ratio (AOR) 2.6; 95% confidence interval (CI) [2.1-3.2]] and 1.7 times more likely to smoke 20 or more cigarettes a day (p = 0.003; AOR 1.7; 95% CI [1.2-2.4]) than controls. Tobacco use was associated with an earlier age at psychosis onset (β = -2.3; p ⩽ 0.001; 95% CI [-3.7 to -0.9]) and was 1.3 times more frequent in FEP patients with a diagnosis of schizophrenia than in other diagnoses of psychosis (AOR 1.3; 95% CI [1.0-1.8]); however, these results were no longer significant after controlling for cannabis use.

CONCLUSIONS

Tobacco and heavy-tobacco use are associated with increased odds of FEP. These findings further support the relevance of tobacco prevention in young populations.

Prevalence, incidence, and persistence of psychotic experiences in the general population: results of a 9-year follow-up study

BACKGROUND

Psychotic experiences (PEs) frequently occur and are associated with a range of negative health outcomes. Prospective studies on PEs are scarce, and to date no study investigated PE prevalence, incidence, persistence, their risk indicators, and psychiatric comorbidity, in one dataset. Furthermore, most studies are based on self-report, and it is unclear how this compares to clinical interviews.

METHODS

Data are used from the Netherlands Mental Health Survey and Incidence Study-2 (NEMESIS-2), a psychiatric cohort study among a representative sample of adults (baseline characteristics: N = 6646; 49.6% female; 18-64 years). Results are presented for self-reported and clinically validated PEs. Associations are assessed for mental disorders, socio-demographic, vulnerability, physical health, and substance use factors.

RESULTS

Based on self-report, at baseline 16.5% of respondents had at least one PE in their lifetime, of those, 30.1% also reported a PE at 3-year follow-up. 4.8% had a first PE at 3-year follow up. The 3-year prevalence of PE was associated with almost all studied risk indicators. Generally, the strongest associations were found for mental health disorders. Prevalence and incidence rates were two to three times higher in self-report than in clinical interview but results on associated factors were similar.

CONCLUSIONS

Validated prevalence and incidence estimates of PE are substantially lower than self-reported figures but results on associated factors were similar. Therefore, future studies on associations of PEs can rely on relatively inexpensive self-reports of PEs. The associations between PE and mental disorders underline the importance of assessment of PE in general practice.

Schizotypal dimensions are associated with current but not former tobacco consumption

OBJECTIVES

We aimed to study the relationship between tobacco smoking and attenuated psychosis measures taking into account several aspects of tobacco consumption that to date have not been explored and that could help understand this association, such as age of onset, the influence of former consumption and the duration of abstinence.

METHODS

We investigated, in a sample of 580 students, the relationship between schizotypy (using the schizotypal personality questionnaire-brief in a Likert format) and smoking status, nicotine dependence (measured with the Fagerström test for nicotine dependence), age of onset of smoking and in former smokers, duration of smoking abstinence.

RESULTS

35.2% of the students were current smokers and 13.4% were former smokers. We found that current but not former smokers had higher scores of schizotypy (total, positive and disorganized) than non-smokers. We found no association between schizotypy scores and nicotine dependence or earlier age of onset of smoking. The duration of smoking abstinence, in former smokers, was inversely correlated to the score of positive and total schizotypy.

CONCLUSIONS

Our results suggest that tobacco has a reversible effect on schizotypy, but more studies with a different design (controlled, longitudinal) and a more thorough exploration of potential confounders (e.g. cannabis) are needed before a firm conclusion can be reached.

Sleep disturbance and psychotic-like experiences among urban adolescents with and without parental migration

Aim

Sleep disturbance was closely associated with an increased risk of psychotic-like experiences (PLEs). This study aims to explore the association between sleep disturbance and PLEs among urban adolescents with and without parental migration.

Methods

A total of 67, 532 urban Chinese adolescents were recruited in a large web-based survey during April 21st to May 12th, 2021. In our study, sleep disturbance, PLEs, family function, school climate, and a series of socio-demographic were assessed. And hierarchical logistic regression analyses were performed to examine influential factors associated with PLEs.

Results

Urban left-behind children (LBC) had a higher prevalence of sleep disturbance and PLEs than non-LBC. After controlling for confounders, parental migration was associated to PLEs with weak significance (OR = 1.19). Meanwhile, sleep disturbance was found to be a robust risk factor for PLEs (OR = 3.84 and 4.09), with or without the effect of parental migration. In addition, better family function and school climate has significant association with decreased risk of PLEs.

Conclusion

Adolescents with sleep disturbance are more likely to report PLEs. Adolescents' PLEs preventive strategies could focus on reducing sleep disturbance related symptoms as well as improving family function and school climate.

Visual Hallucinations following Coronary Artery Bypass Grafting: A Prospective Study

Background and Objectives: After major heart surgery, some patients report visual hallucinations that cannot be attributed to psychosis or delirium. This study aimed to investigate the hallucination incidence in patients after coronary artery bypass grafting with (on-pump) and without (off-pump) extracorporeal circulation. Materials and Methods: A total of 184 consecutive patients listed for elective on- or off-pump coronary artery bypass grafting were prospectively enrolled into the study. Preoperative baseline investigations 24–48 h before surgery (t0) and postoperative follow-up 24–48 h (t1) and 5–6 days (t2) after surgery included cognitive testing and a clinical visual acuity test (Landolt rings). Patients reporting visual hallucinations were interviewed using a structured survey to record the type, timing, duration, and frequency of their hallucinations. All the patients received a neurological examination and cranial magnetic resonance imaging if indicated. Results: Of the patients in the sample, 155 patients underwent on-pump bypass surgery, and 29 patients received off-pump surgery. Of these, 25 patients in the on-pump group, but none in the off-pump group, reported transient visual hallucinations (p = 0.020), which could not be attributed to stroke, delirium, psychosis, migraine, or severely impaired vision. Significant correlations were observed for the occurrence of visual hallucinations and the amount of nicotine consumption and aortic clamp/extracorporeal circulation time. Conclusions: Transient visual hallucinations occur in a noticeable proportion of patients after on-pump heart surgery. Knowledge of the phenomenon’s benignity is important for patients to prevent anxiety and uncertainty and for treating physicians to avoid unnecessary medication and drug-induced delirium.

Consciousness alterations in a cohort of young Swiss men: Associations with substance use and personality traits

BACKGROUND

Substance-induced consciousness alterations (CA) have mainly been studied among users of psychedelics but not among people using street drugs.

AIMS

Explore occurrences of three different types of substance-induced CA [ego dissolution (ED), visual pseudo-hallucinations (VPH), anxiety/paranoia (A/P)] and their perceived influences on life, together with their associations with substance use and personality correlates in a general population sample of 25-year-old men.

METHODS

2,796 young Swiss men lifetime substance users completed a self-report questionnaire including history of use (never, former, and current) of different substances categories (psychedelics, cocaine, psychostimulants, ecstasy, MDMA, and other drugs), substance-induced ego dissolution (ED), visual pseudo-hallucinations (VPH) and anxiety/paranoia (A/P), the influence of these CA experiences on life, and personality traits (sensation seeking, sociability, anxiety-neuroticism, and aggression-hostility).

RESULTS

32.2% reported at least one CA (i.e., ED, VPH or A/P), with 20.5% reporting ED, 16.7% VPH, and 14.6% A/P. Former and current use of psychedelics and ketamine was significantly associated with occurrences of all three types of CAs and with a positive influence of CA on life. Associations between the former and current use of other substances and the different types of CA were less consistent, and perceived influences on life were not statistically significant. Sociability was negatively associated with occurrences of all three types of CA. Positive associations were found between anxiety-neuroticism and ED and A/P, between aggression-hostility and A/P, and between sensation seeking and ED and VPH.

CONCLUSION

This study supports the potential for psychedelics to induce CAs perceived as beneficial to life among people using street drugs, possibly reflecting the mechanism underlying the therapeutic potential of psychedelics.

Genetic overlap and causal associations between smoking behaviours and mental health

Cigarette smoking is a modifiable behaviour associated with mental health. We investigated the degree of genetic overlap between smoking behaviours and psychiatric traits and disorders, and whether genetic associations exist beyond genetic influences shared with confounding variables (cannabis and alcohol use, risk-taking and insomnia). Second, we investigated the presence of causal associations between smoking initiation and psychiatric traits and disorders. We found significant genetic correlations between smoking and psychiatric disorders and adult psychotic experiences. When genetic influences on known covariates were controlled for, genetic associations between most smoking behaviours and schizophrenia and depression endured (but not with bipolar disorder or most psychotic experiences). Mendelian randomization results supported a causal role of smoking initiation on psychiatric disorders and adolescent cognitive and negative psychotic experiences, although not consistently across all sensitivity analyses. In conclusion, smoking and psychiatric disorders share genetic influences that cannot be attributed to covariates such as risk-taking, insomnia or other substance use. As such, there may be some common genetic pathways underlying smoking and psychiatric disorders. In addition, smoking may play a causal role in vulnerability for mental illness.

Link between personality and response to THC exposure

The effects of cannabis reported by users range from experiences of euphoria and anxiolytic effects to paranoia, anxiety, and increased risk of depression. Attempts to reconcile the apparent contradictions in user response have not been conclusive. Here, we utilized selectively-bred stress-resilient socially dominant (Dom) and stress-sensitive socially submissive (Sub) mice to elucidate this contradiction. Following short-term, repeated treatment with delta-9-tetrahydrocannabinol (THC) at two different doses (1.5 mg/kg and 15 mg/kg), Sub mice presented significant place-aversion in a Conditioned Place Preference paradigm at a high dose, whereas Dom mice displayed no place preference or aversion. Forced Swim test conducted after 6-week of washout period, revealed differential impact of the two THC doses depending upon behavioral pattern. Specifically, the low dose alleviated depressive-like behavior in Sub mice, while the high dose produced the opposite effect in Dom mice. Interestingly, corticosterone concentration in serum was elevated at the high dose regardless of the mice-population tested. We conclude here that differences in dominance behavior and stress vulnerability are involved in the regulation of cannabis response among users and should be considered when prescribing THC-containing medications to patients.

A Twin Study on the Association Between Psychotic Experiences and Tobacco Use During Adolescence

OBJECTIVE

Psychotic experiences (PE) are dimensional phenomena in the general population that resemble psychotic symptoms, such as paranoia and hallucinations. This is the first twin study to explore the degree to which tobacco use and PE share genetic or environmental influences. Previous studies on the association between adolescent tobacco use and PE have not considered PE dimensionally, included negative symptoms, or accounted for confounding by sleep disturbance and stressful life events.

METHOD

An unselected adolescent twin sample (N = 3,787 pairs; mean age = 16.16 years) reported on PE (paranoia, hallucinations, cognitive disorganization, grandiosity, and anhedonia) and regularity of tobacco use. Parents rated the twins' negative symptoms. Regression analyses were conducted while adjusted for sociodemographic characteristics, prenatal maternal smoking, cannabis use, sleep disturbance, and stressful life events. Bivariate twin modeling was used to estimate the degree of genetic and common and unique environmental influences shared between tobacco use and PE.

RESULTS

Regular smokers were significantly more likely to experience paranoia, hallucinations, cognitive disorganization, and negative symptoms (β = 0.17-0.34), but not grandiosity or anhedonia, than nonsmokers, after adjustment for confounders. Paranoia, hallucinations, and cognitive disorganization correlated ≥0.15 with tobacco use (r = 0.15-0.21, all p < .001). Significant genetic correlations (r_A=0.37-0.45) were found. Genetic influences accounted for most of the association between tobacco use and paranoia (84%) and cognitive disorganization (81%). Familial influences accounted for 80% of the association between tobacco use and hallucinations.

CONCLUSION

Tobacco use and PE during adolescence were associated after adjustment for confounders. They appear to co-occur largely because of shared genetic influences.

The association between psychotic experiences and health-related quality of life: a cross-national analysis based on World Mental Health Surveys

Psychotic experiences (PEs) are associated with a range of mental and physical disorders, and disability, but little is known about the association between PEs and aspects of health-related quality of life (HRQoL). We aimed to investigate the association between PEs and five HRQoL indicators with various adjustments. Using data from the WHO World Mental Health surveys (n = 33,370 adult respondents from 19 countries), we assessed for PEs and five HRQoL indicators (self-rated physical or mental health, perceived level of stigma (embarrassment and discrimination), and social network burden). Logistic regression models that adjusted for socio-demographic characteristics, 21 DSM-IV mental disorders, and 14 general medical conditions were used to investigate the associations between the variables of interest. We also investigated dose-response relationships between PE-related metrics (number of types and frequency of episodes) and the HRQoL indicators. Those with a history of PEs had increased odds of poor perceived mental (OR = 1.5, 95% CI = 1.2-1.9) and physical health (OR = 1.3, 95% CI = 1.0-1.7) after adjustment for the presence of any mental or general medical conditions. Higher levels of perceived stigma and social network burden were also associated with PEs in the adjusted models. Dose-response associations between PE type and frequency metrics and subjective physical and mental health were non-significant, except those with more PE types had increased odds of reporting higher discrimination (OR = 2.2, 95% CI = 1.3-3.5). Our findings provide novel insights into how those with PEs perceive their health status.

A systematic review and meta-analysis of mental health service use in people who report psychotic experiences

BACKGROUND

Self-reported psychotic experiences (PEs) are associated with psychopathology of all kinds, not just psychoses. However, systematic reviews on the relevance of this for health services are unavailable. Furthermore, whether association with service use is confounded by other psychopathology is unknown, and is relevant to prevention and treatment.

OBJECTIVES

Literature examining associations between PEs and service use was systematically reviewed. Study quality and the direction and extent of any associations were assessed, and meta-analysis conducted.

METHODS

Systematic review and meta-analysis was carried out as per PRISMA guidelines. A search of electronic databases was performed based on free-text and structured terms. Included studies were evaluated by two raters using a structured tool and estimates extracted for reporting.

RESULTS

Thirteen studies were returned. We found two prospective studies, and a minority of studies accounted for concurrent psychopathology, limiting our ability to test our main hypotheses. Five studies reported associations by different types of service use. Almost all studies assessed service use by self-report. Meta-analysis suggested that people who reported PEs were around twice as likely to report service use compared to those who did not (pooled OR for all included studies: 2.20,95% confidence intervals (95%CI): 1.66,2.91).

CONCLUSIONS

There was consistent evidence of association between PEs and mental health service use at the general population level. However, evidence for causation was poor due to a limited number of studies. Whether increased service use in this group is solely attributable to PEs, and therefore whether interventions aimed at limiting/preventing PEs might be effective, requires studies focusing on the relationships between PEs, psychopathology and service use.

The associations between psychotic experiences and substance use and substance use disorders: findings from the World Health Organization World Mental Health surveys

BACKGROUND AND AIMS

Prior research has found bidirectional associations between psychotic experiences (PEs) and selected substance use disorders. We aimed to extend this research by examining the bidirectional association between PEs and various types of substance use (SU) and substance use disorders (SUDs), and the influence of antecedent mental disorders on these associations.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

We used data from the World Health Organization World Mental Health surveys. A total of 30 902 adult respondents across 18 countries were assessed for (a) six types of life-time PEs, (b) a range of types of SU and DSM-IV SUDs and (c) mental disorders using the Composite International Diagnostic Interview. Discrete-time survival analyses based on retrospective age-at-onset reports examined the bidirectional associations between PEs and SU/SUDs controlling for antecedent mental disorders.

FINDINGS

After adjusting for demographics, comorbid SU/SUDs and antecedent mental disorders, those with prior alcohol use disorders [odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.2-2.0], extra-medical prescription drug use (OR = 1.5, 95% CI = 1.1-1.9), alcohol use (OR = 1.4, 95% CI = 1.1-1.7) and tobacco use (OR = 1.3, 95% CI = 1.0-1.8) had increased odds of subsequent first onset of PEs. In contrast, those with temporally prior PEs had increased odds of subsequent onset of tobacco use (OR = 1.5, 95% CI = 1.2-1.9), alcohol use (OR = 1.3, 95% CI = 1.1-1.6) or cannabis use (OR = 1.3, 95% CI = 1.0-1.5) as well as of all substance use disorders (ORs ranged between 1.4 and 1.5). There was a dose response relationship between both count and frequency of PEs and increased subsequent odds of selected SU/SUDs.

CONCLUSIONS

Associations between psychotic experiences (PEs) and substance use/substance use disorders (SU/SUDs) are often bidirectional, but not all types of SU/SUDs are associated with PEs. These findings suggest that it is important to be aware of the presence of PEs within those with SUDs or at risk of SUDs, given the plausibility that they may each impact upon the other.

Psychotic experiences and religiosity: data from the WHO World Mental Health Surveys

OBJECTIVES

Religiosity is often associated with better health outcomes. The aim of the study was to examine associations between psychotic experiences (PEs) and religiosity in a large, cross-national sample.

METHODS

A total of 25 542 adult respondents across 18 countries from the WHO World Mental Health Surveys were assessed for PEs, religious affiliation and indices of religiosity, DSM-IV mental disorders and general medical conditions. Logistic regression models were used to estimate the association between PEs and religiosity with various adjustments.

RESULTS

Of 25 542 included respondents, 85.6% (SE = 0.3) (n = 21 860) respondents reported having a religious affiliation. Overall, there was no association between religious affiliation status and PEs. Within the subgroup having a religious affiliation, four of five indices of religiosity were significantly associated with increased odds of PEs (odds ratios ranged from 1.3 to 1.9). The findings persisted after adjustments for mental disorders and/or general medical conditions, as well as religious denomination type. There was a significant association between increased religiosity and reporting more types of PEs.

CONCLUSIONS

Among individuals with religious affiliations, those who reported more religiosity on four of five indices had increased odds of PEs. Focussed and more qualitative research will be required to unravel the interrelationship between religiosity and PEs.

Tobacco smoking is associated with psychotic experiences in the general population of South London

BACKGROUND

The association between cigarette smoking and psychosis remains unexplained, but could relate to causal effects in both directions, confounding by socioeconomic factors, such as ethnicity, or use of other substances, including cannabis. Few studies have evaluated the association between cigarettes and psychotic experiences (PEs) in diverse, inner-city populations, or relationships with number of cigarettes consumed.

METHODS

We assessed associations and dose-response relationships between cigarette smoking and PEs in a cross-sectional survey of household residents (n = 1680) in South East London, using logistic regression to adjust for cannabis use, other illicit substances, and socioeconomic factors, including ethnicity.

RESULTS

We found association between any PEs and daily cigarette smoking, which remained following adjustment for age, gender, ethnicity, cannabis and use of illicit stimulant drugs (fully adjusted odds ratio 1.47, 95% confidence interval 1.01-2.15). Fully adjusted estimates for the association, and with number of PEs, increased with number of cigarettes smoked daily, implying a dose-response effect (p = 0.001 and <0.001, respectively). Odds of reporting any PEs in ex-smokers were similar to never-smokers.

CONCLUSIONS

In this diverse epidemiological sample, association between smoking and PEs was not explained by confounders such as cannabis or illicit drugs. Daily cigarette consumption showed a dose-response relationship with the odds of reporting PEs, and of reporting a greater number of PEs. There was no difference in odds of reporting PEs between ex-smokers and never-smokers, raising the possibility that the increase in PEs associated with smoking may be reversible.

The association between psychotic experiences and disability: results from the WHO World Mental Health Surveys

OBJECTIVE

While psychotic experiences (PEs) are known to be associated with a range of mental and general medical disorders, little is known about the association between PEs and measures of disability. We aimed to investigate this question using the World Mental Health surveys.

METHOD

Lifetime occurrences of six types of PEs were assessed along with 21 mental disorders and 14 general medical conditions. Disability was assessed with a modified version of the WHO Disability Assessment Schedule. Descriptive statistics and logistic regression models were used to investigate the association between PEs and high disability scores (top quartile) with various adjustments.

RESULTS

Respondents with PEs were more likely to have top quartile scores on global disability than respondents without PEs (19.1% vs. 7.5%; χ²  = 190.1, P < 0.001) as well as greater likelihood of cognitive, social, and role impairment. Relationships persisted in each adjusted model. A significant dose-response relationship was also found for the PE type measures with most of these outcomes.

CONCLUSIONS

Psychotic experiences are associated with disability measures with a dose-response relationship. These results are consistent with the view that PEs are associated with disability regardless of the presence of comorbid mental or general medical disorders.

The association between childhood adversities and subsequent first onset of psychotic experiences: a cross-national analysis of 23 998 respondents from 17 countries

BACKGROUND

Although there is robust evidence linking childhood adversities (CAs) and an increased risk for psychotic experiences (PEs), little is known about whether these associations vary across the life-course and whether mental disorders that emerge prior to PEs explain these associations.

METHOD

We assessed CAs, PEs and DSM-IV mental disorders in 23 998 adults in the WHO World Mental Health Surveys. Discrete-time survival analysis was used to investigate the associations between CAs and PEs, and the influence of mental disorders on these associations using multivariate logistic models.

RESULTS

Exposure to CAs was common, and those who experienced any CAs had increased odds of later PEs [odds ratio (OR) 2.3, 95% confidence interval (CI) 1.9-2.6]. CAs reflecting maladaptive family functioning (MFF), including abuse, neglect, and parent maladjustment, exhibited the strongest associations with PE onset in all life-course stages. Sexual abuse exhibited a strong association with PE onset during childhood (OR 8.5, 95% CI 3.6-20.2), whereas Other CA types were associated with PE onset in adolescence. Associations of other CAs with PEs disappeared in adolescence after adjustment for prior-onset mental disorders. The population attributable risk proportion (PARP) for PEs associated with all CAs was 31% (24% for MFF).

CONCLUSIONS

Exposure to CAs is associated with PE onset throughout the life-course, although sexual abuse is most strongly associated with childhood-onset PEs. The presence of mental disorders prior to the onset of PEs does not fully explain these associations. The large PARPs suggest that preventing CAs could lead to a meaningful reduction in PEs in the population.

The Bidirectional Associations Between Psychotic Experiences and DSM-IV Mental Disorders

OBJECTIVE

While it is now recognized that psychotic experiences are associated with an increased risk of later mental disorders, we lack a detailed understanding of the reciprocal time-lagged relationships between first onsets of psychotic experiences and mental disorders. Using data from World Health Organization World Mental Health (WMH) Surveys, the authors assessed the bidirectional temporal associations between psychotic experiences and mental disorders.

METHOD

The WMH Surveys assessed lifetime prevalence and age at onset of psychotic experiences and 21 common DSM-IV mental disorders among 31,261 adult respondents from 18 countries. Discrete-time survival models were used to examine bivariate and multivariate associations between psychotic experiences and mental disorders.

RESULTS

Temporally primary psychotic experiences were significantly associated with subsequent first onset of eight of the 21 mental disorders (major depressive disorder, bipolar disorder, generalized anxiety disorder, social phobia, posttraumatic stress disorder, adult separation anxiety disorder, bulimia nervosa, and alcohol abuse), with odds ratios ranging from 1.3 (95% CI=1.2-1.5) for major depressive disorder to 2.0 (95% CI=1.5-2.6) for bipolar disorder. In contrast, 18 of 21 primary mental disorders were significantly associated with subsequent first onset of psychotic experiences, with odds ratios ranging from 1.5 (95% CI=1.0-2.1) for childhood separation anxiety disorder to 2.8 (95% CI=1.0-7.8) for anorexia nervosa.

CONCLUSIONS

While temporally primary psychotic experiences are associated with an elevated risk of several subsequent mental disorders, these data show that most mental disorders are associated with an elevated risk of subsequent psychotic experiences. Further investigation of the underlying factors accounting for these time-order relationships may shed light on the etiology of psychotic experiences.

Attenuated Positive Psychotic Symptoms in Relation to Cigarette Smoking in a Nonclinical Population

INTRODUCTION

This study explored the association between cigarette smoking and attenuated positive psychotic symptoms in a young adult nonclinical sample.

METHODS

Undergraduates (N = 930), aged 18-35 years (26.3% male), completed a battery of self-report measures assessing subthreshold psychotic symptoms, cigarette smoking behavior/dependence, and drug use.

RESULTS

Individuals endorsing a greater number of attenuated positive psychotic symptoms were more likely to be smokers. Exploratory analyses indicated that the odds of being a smoker were two times greater for those at potential higher risk for psychosis compared with individuals at lower risk. Results were consistent after adjusting for sex and other drug use.

CONCLUSIONS

In line with findings from psychotic populations, results suggest that attenuated positive psychotic symptoms, particularly those endorsed as distressing in a nonclinical, undergraduate population, are related to cigarette smoking.

IMPLICATIONS

Even in nonclinical, undergraduate populations, subthreshold psychotic symptoms are related to cigarette smoking, and cigarette smokers are twice as likely to be considered at potentially higher risk for psychosis compared with noncigarette smokers. In summary, there may be a threshold whereby psychotic symptoms confer increased risk for nicotine consumption, with endorsement of a greater number of distressing subthreshold psychotic symptoms increasing the likelihood of cigarette use.

Psychotic-like experiences and disordered eating in the English general population

There are no studies on psychotic-like experiences (PLEs) and disordered eating in the general population. We aimed to assess this association in the English adult population. Data from the 2007 Adult Psychiatric Morbidity Survey (APMS) were analyzed. This was a nationally representative survey comprising 7403 English adults aged ≥16 years. The Psychosis Screening Questionnaire was used to identify the past 12-month occurrence of five forms of psychotic symptoms. Questions from the five-item SCOFF screening instrument were used to identify those with eating disorder (ED) symptoms and possible ED in the past year. The prevalence of any PLE was 5.1% (female) and 5.4% (male), while that of possible ED was 9.0% (female) and 3.5% (male). After adjustment for potential confounders, possible ED was associated with hypomania/mania in females (OR=3.23 95%CI=1.002-10.39), strange experiences [females (OR=1.85 95%CI=1.07-3.20) and males (OR=3.54 95%CI=1.65-7.57)], and any PLE in males (OR=3.44 95%CI=1.85-6.39). An interaction analysis revealed that the association was stronger among males for: auditory hallucinations and uncontrolled eating; and any PLE with uncontrolled eating, food dominance, and possible ED. Clinical practitioners should be aware that PLEs and disordered eating behavior often coexist. When one condition is detected, screening for the other may be advisable, especially among males.

Age of Onset and Lifetime Projected Risk of Psychotic Experiences: Cross-National Data From the World Mental Health Survey

BACKGROUND

Given the early age of onset (AOO) of psychotic disorders, it has been assumed that psychotic experiences (PEs) would have a similar early AOO. The aims of this study were to describe (a) the AOO distribution of PEs, (b) the projected lifetime risk of PEs, and (c) the associations of PE AOO with selected PE features.

METHODS

Data came from the WHO World Mental Health (WMH) surveys. A total of 31 261 adult respondents across 18 countries were assessed for lifetime prevalence of PE. Projected lifetime risk (at age 75 years) was estimated using a 2-part actuarial method. AOO distributions were described for the observed and projected estimates. We examined associations of AOO with PE type metric and annualized PE frequency.

RESULTS

Projected lifetime risk for PEs was 7.8% (SE = 0.3), slightly higher than lifetime prevalence (5.8%, SE = 0.2). The median (interquartile range; IQR) AOO based on projected lifetime estimates was 26 (17-41) years, indicating that PEs commence across a wide age range. The AOO distributions for PEs did not differ by sex. Early AOO was positively associated with number of PE types (F = 14.1, P < .001) but negatively associated with annualized PE frequency rates (F = 8.0, P < .001).

DISCUSSION

While most people with lifetime PEs have first onsets in adolescence or young adulthood, projected estimates indicate that nearly a quarter of first onsets occur after age 40 years. The extent to which late onset PEs are associated with (a) late onset mental disorders or (b) declining cognitive and/or sensory function need further research.

Age at first tobacco use and risk of subsequent psychosis-related outcomes: A birth cohort study

OBJECTIVE

Compared to the substantial body of research examining links between cannabis use and psychosis, there has been relatively little attention to the role of tobacco as a potential risk factor for psychosis. This study explored the association between age at first tobacco use and psychosis-related outcomes in a birth cohort.

METHOD

This study is based on a large birth cohort (the Mater-University Study of Pregnancy). At approximately 21 years of age, cohort members (N = 3752) were assessed for three psychosis-related outcomes (International Classification of Diseases non-affective psychosis, the presence of any hallucination and total count of delusional-like experiences) with the Composite International Diagnostic Interview and the Peters Delusional Inventory. Associations between age at first tobacco use and psychosis-related outcomes were examined using logistic regression in a model (a) adjusted for sex and age and (b) in a second model excluding all respondents who had a history of past problematic and current cannabis use.

RESULTS

When adjusted for age and sex, those who commenced tobacco at 15 years of age or younger were significantly more likely to (a) have non-affective psychosis, (b) be in the highest quartile of total score of the Peters Delusional Inventory and (c) report hallucinations. After excluding all those with a history of a cannabis use disorder, or who were current (last month) cannabis users, a significant association between age at first tobacco use and the presence of hallucinations persisted.

CONCLUSION

There is an association between age at first tobacco use and subsequent psychosis-related outcomes in young adults. While the findings cannot be used to deduce causality, it adds weight to the hypothesis that early tobacco use may contribute to the risk of developing psychosis-related outcomes.

Psychotic symptoms and smoking in 44 countries

OBJECTIVE

To assess the association between psychotic symptoms and smoking among community-dwelling adults in 44 countries.

METHOD

Data from the World Health Survey (WHS) for 192 474 adults aged ≥18 years collected in 2002-2004 were analyzed. The Composite International Diagnostic Interview was used to identify four types of past 12-month psychotic symptoms. Smoking referred to current daily and non-daily smoking. Heavy smoking was defined as smoking ≥30 tobacco products/day.

RESULTS

The pooled age-sex-adjusted OR (95% CI) of psychotic symptoms (i.e., at least one psychotic symptom) for smoking was 1.35 (1.27-1.43). After adjustment for potential confounders, compared to those with no psychotic symptoms, the ORs (95% CIs) for smoking for 1, 2, and ≥3 psychotic symptoms were 1.20 (1.08-1.32), 1.25 (1.08-1.45), and 1.36 (1.13-1.64) respectively. Among daily smokers, psychotic symptoms were associated with heavy smoking (OR = 1.45, 95% CI = 1.10-1.92), and individuals who initiated daily smoking at ≤15 years of age were 1.22 (95% CI = 1.05-1.42) times more likely to have psychotic symptoms.

CONCLUSIONS

An increased awareness that psychotic symptoms are associated with smoking is important from a public health and clinical point of view. Future studies that investigate the underlying link between psychotic symptoms and smoking prospectively are warranted.

Psychotic Experiences in the General Population: A Cross-National Analysis Based on 31,261 Respondents From 18 Countries

IMPORTANCE

Community-based surveys find that many otherwise healthy individuals report histories of hallucinations and delusions. To date, most studies have focused on the overall lifetime prevalence of any of these psychotic experiences (PEs), which might mask important features related to the types and frequencies of PEs.

OBJECTIVE

To explore detailed epidemiologic information about PEs in a large multinational sample.

DESIGN, SETTING, AND PARTICIPANTS

We obtained data from the World Health Organization World Mental Health Surveys, a coordinated set of community epidemiologic surveys of the prevalence and correlates of mental disorders in representative household samples from 18 countries throughout the world, from 2001 through 2009. Respondents included 31,261 adults (18 years and older) who were asked about lifetime and 12-month prevalence and frequency of 6 types of PEs (2 hallucinatory experiences and 4 delusional experiences). We analyzed the data from March 2014 through January 2015.

MAIN OUTCOMES AND MEASURES

Prevalence, frequency, and correlates of PEs.

RESULTS

Mean lifetime prevalence (SE) of ever having a PE was 5.8% (0.2%), with hallucinatory experiences (5.2% [0.2%]) much more common than delusional experiences (1.3% [0.1%]). More than two-thirds (72.0%) of respondents with lifetime PEs reported experiencing only 1 type. Psychotic experiences were typically infrequent, with 32.2% of respondents with lifetime PEs reporting only 1 occurrence and 31.8% reporting only 2 to 5 occurrences. We found a significant relationship between having more than 1 type of PE and having more frequent PE episodes (Cochran-Armitage z = -10.0; P < .001). Lifetime prevalence estimates (SEs) were significantly higher among respondents in middle- and high-income countries than among those in low-income countries (7.2% [0.4%], 6.8% [0.3%], and 3.2% [0.3%], respectively; χ²₂ range, 7.1-58.2; P < .001 for each) and among women than among men (6.6% [0.2%] vs 5.0% [0.3%]; χ²₁ = 16.0; P < .001). We found significant associations with lifetime prevalence of PEs in the multivariate model among nonmarried compared with married respondents (χ²₂ = 23.2; P < .001) and among respondents who were not employed (χ²₄= 10.6; P < .001) and who had low family incomes (χ²₃ = 16.9; P < .001).

CONCLUSIONS AND RELEVANCE

The epidemiologic features of PEs are more nuanced than previously thought. Research is needed that focuses on similarities and differences in the predictors of the onset, course, and consequences of distinct PEs.

Psychotic experiences and risk of death in the general population: 24-27 year follow-up of the Epidemiologic Catchment Area study

BACKGROUND

Psychotic experiences are common in the general population and are associated with adverse psychiatric and social outcomes, even in the absence of a psychotic disorder.

AIMS

To examine the association between psychotic experiences and mortality over a 24-27 year period.

METHOD

We used data on 15 049 adult participants from four sites of the Epidemiologic Catchment Area baseline survey in the USA in the early 1980s, linked to the National Death Index and other sources of vital status up until 2007. Psychotic experiences were assessed by the Diagnostic Interview Schedule.

RESULTS

Lifetime psychotic experiences at baseline (n = 855; weighted prevalence, 5.5%) were significantly associated with all-cause mortality at follow-up after adjustment for sociodemographic characteristics and psychiatric diagnoses, including schizophrenia spectrum disorders (P<0.05). Baseline psychotic experiences were associated with over 5 years' shorter median survival time. Among the underlying causes of death, suicide had a particularly high hazard ratio (9.16, 95% CI 3.19-26.29).

CONCLUSIONS

Future research needs to explore the association of psychotic experiences with physical health and lifestyle factors that may mediate the relationship of psychotic experiences with mortality.

Towards a cognitive model of hallucinations in the course of alcohol dependence? A source monitoring-based pilot study

BACKGROUND

We investigated whether source-monitoring deficits (here a discrimination between imagined and performed actions) underlie hallucinations among patients with a history of hallucinations in the course of their alcohol dependence.

METHOD

We assessed 29 patients with alcohol dependence who had no history of hallucinations during their course of alcoholism and 29 patients with a history of at least one episode of hallucinations of any modality during their course of alcohol dependency. The control group consisted of 24 healthy participants. Participants were assessed with an action memory task. Simple actions were presented to the participants verbally or non-verbally. Some actions were performed physically and others were imagined. In the recognition phase, participants were asked whether the action was presented verbally or non-verbally (action presentation type discrimination) and whether the action was performed or imagined (self-monitoring). A confidence score related to self-monitoring responses was also obtained.

RESULTS

Alcoholics with a history of hallucinations misremembered imagined actions as perceived ones more frequently than patients without hallucinations, but not the reverse. Only patients with a history of hallucinations committed more errors of this type than healthy subjects. There were no group differences regarding discrimination between an action presentation type. Both clinical groups committed errors with a higher degree of confidence than healthy subjects.

CONCLUSIONS

Our results tentatively suggest that a specific type of source-monitoring deficit (i.e., confusing imagery with reality) may be involved in the hallucinations in patients with alcohol dependence. The findings are discussed in the light of a transdiagnostic approach to hallucinations.

Cannabis use is a better indicator of poor mental health in women than in men: a cross-sectional study in young adults from the general population

Cannabis use is a known risk factor for a range of mental health problems, but less is known on the association with general mental health. We aim to explore the relationship between cannabis use and general mental health. We did a cross-sectional online survey of 1,929 young adults aged 18-30 years. Participants reported socio-demographic data, substance use and the Symptom Checklist-90 (SCL-90). Monthly cannabis use was associated with a higher total score on the SCL-90, both in a crude (OR 1.94, 95% CI 1.57-2.38) and fully adjusted model (OR 1.48, 95% CI 1.07-2.03). The association between cannabis and mental health was stronger in women and weekly users, and was independent of age at first use of cannabis. We conclude that moderate cannabis use is associated with general mental health problems in young adulthood. This relationship is independent of age at first use and of other risk factors, and is strongest in women.

Cigarette smoking and cannabis use are equally strongly associated with psychotic-like experiences: a cross-sectional study in 1929 young adults

BACKGROUND

Cannabis use is associated with increased risk for psychotic-like experiences (PLEs) and psychotic disorders. It remains unclear whether this relationship is causal or due to confounding.

METHOD

A total of 1929 young adults aged 18-30 years participated in a nationwide internet-based survey in The Netherlands and gave information on demographics, substance use and parental psychiatric illness and completed the Community Assessment of Psychic Experiences (CAPE).

RESULTS

Cigarette smoking and cannabis use were equally strongly associated with the frequency of PLEs in a fully adjusted model (β = 0.098 and 0.079 respectively, p < 0.05). Cannabis use was associated with distress from PLEs in a model adjusted for an elaborate set of confounders excluding smoking (β = 0.082, p < 0.05). However, when cigarette smoking was included in the model, cannabis use was not a significant predictor of distress from PLEs. Cigarette smoking remained associated with distress from PLEs in a fully adjusted model (β = 0.107, p < 0.001).

CONCLUSIONS

Smoking is an equally strong independent predictor of frequency of PLEs as monthly cannabis use. Our results suggest that the association between moderate cannabis use and PLEs is confounded by cigarette smoking.

Service use for mental health problems in people with delusional-like experiences: a nationwide population based survey

Objective

Previous population-based studies have found that delusional-like experiences (DLEs) are prevalent in the community, and are associated with a wide range of mental health disorders. The aim of the study was to investigate mental health service use by people with DLEs.

Methods

Subjects were drawn from the Australian National Survey of Mental Health and Wellbeing 2007 of 8 841community residents aged between 16 and 85 years. The Composite International Diagnostic Interview (CIDI) was used to identify DLEs. Service utilization was assessed using a module that elicited information about hospital admissions, consultations with various health professionals, and prescription medication use. This study focussed on service use for mental health problems. We used logistic regression to examine the association, adjusting for potential confounding factors.

Results

Of 8 773 included participants, 8.4% (n = 776) positively endorsed one or more DLEs. With respect to consultations for mental health needs, individuals who endorsed DLEs were more likely to consult health professionals compared with those who did not endorse DLEs. Individuals with DLEs were also more likely to use prescription medicine. When we repeated the main analysis in a subgroup excluding any CIDI diagnosis of mental health disorders the results remained largely unchanged.

Conclusions

DLEs are common in the general population, and individuals with DLEs have an increased rate of accessing services for their mental health needs. Individuals endorsing both DLEs and increased help-seeking may identify a group of vulnerable people who have increased risk of developing psychotic illnesses later in life. This needs closer scrutiny in longitudinal prospective studies.

Dose-response effect between cannabis use and psychosis liability in a non-clinical population: evidence from a snowball sample

This study aimed to explore the associations between daily cannabis use and the specific profiles of subclinical symptoms in a non-clinical population obtained through snowball sampling, taking into account alcohol use, other drug use, social exclusion and age at onset of cannabis use. We included 85 daily cannabis users and 100 non-daily cannabis users. Both the case and the control populations were identified by snowball sampling. Daily cannabis use was associated with more alcohol intake and other drug use, as well as with early onset in the use of cannabis. Daily cannabis use appeared to exert a dose-response effect on first-rank symptoms, mania symptoms and auditory hallucinations, even after adjusting for sex, age, other drug use, social exclusion and age at onset of cannabis use. The paranoid dimension was only associated with the heaviest consumption of cannabis. Initial age of cannabis use modified the effects of daily cannabis use on the first-rank and voices experiences. Daily cannabis use was associated with significantly more first-rank and voices experiences among those subjects who started to use cannabis before 17 years of age. Our study supports the association of psychotic experiences with cannabis use even among non-psychotic subjects.

The heritability of delusional-like experiences

OBJECTIVE

Delusional-like experiences (DLE) are common in the general community and are associated with a family history of mental illness. The aim of this study was to estimate the heritability of DLE.

METHOD

The Peter's Delusional Inventory (PDI) was administered to a population-based cohort of mothers (n = 2861, aged 35-67 years) and their adult offspring (n = 3079, aged 18-23 years). Heritability of DLE was estimated from the sum scores of the 21 item PDI under the assumption that the covariance between mother-offspring scores is attributable to shared additive genetic factors.

RESULTS

The means (medians and standard deviations) for the total PDI scores for the mothers and their offspring were 3.6 (3.0, 3.0) and 5.0 (4.0, 3.5), respectively. The Pearson correlation coefficient between mother and offspring PDI scores was 0.17 (P < 0.001). The heritability was estimated to be 0.35 (standard error 0.04).

CONCLUSION

Heritable factors contribute to over a third of the variance of PDI scores in this population. In light of the association between a family history of a wide range of mental disorders and DLE, these experiences may represent a useful quantitative endophenotype for genetic studies of common mental disorders in population settings.

Anxiety and depressive disorders are associated with delusional-like experiences: a replication study based on a National Survey of Mental Health and Wellbeing

OBJECTIVES

There is growing evidence that delusional-like experiences (DLE) are associated with common mental disorders. In particular, a National Mental Health Survey conducted in Australia during 2007 reported an association between DLE and both anxiety disorder and major depressive disorder (MDD). However, the previous study did not examine this association with respect to subtypes of anxiety disorder nor with severity of MDD. The aim of this study was to examine the associations between DLE and both anxiety disorder and MDD in more detail based on an independent population sample.

DESIGN

Cross-sectional study.

SETTING

Subjects were drawn from the Australian Survey of Mental Health and Wellbeing 1997 using a stratified multistage area sampling of persons living in private dwellings in all States and Territories of Australia.

PARTICIPANTS

Approximately 13 600 private dwellings were initially selected with one person aged 18 years or older from each dwelling invited to participate. In total, 10 641 individuals participated in the survey.

PRIMARY AND SECONDARY OUTCOME MEASURES

The Composite International Diagnostic Interview was used to identify individuals with DLE and Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition (DSM IV) lifetime diagnoses of anxiety disorders and MDD. The influence of various anxiety disorders and MDD on DLE was assessed with logistic regression.

RESULTS

Having a lifetime diagnosis of either any anxiety disorder or MDD was significantly associated with the endorsement of DLE. The association was found for each of the main anxiety disorders when examined separately. There was a dose-response relationship between increasing severity of MDD and higher odds of DLE endorsement.

CONCLUSIONS

DLE are associated with a wide range of anxiety disorders and are more prevalent in those with MDD. Understanding the relationship between DLE, anxiety disorders and depression may provide insights into shared pathways that underpin both psychotic disorders and common mental disorders.