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.

The associations between preexisting mental disorders and subsequent onset of chronic headaches: a worldwide epidemiologic perspective

Although there is a significant association between preexisting depression and later onset of chronic headache, the extent to which other preexisting mental disorders are associated with subsequent onset of headache in the general population is not known. Also unknown is the extent to which these associations vary by gender or by life course. We report global data from the WHO's World Mental Health surveys (n = 52,095), in which, by means of the Composite International Diagnostic Interview-3.0, 16 mental disorders from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, were retrospectively assessed in terms of lifetime prevalence and age of onset. Frequent or severe headaches were assessed using self-reports. After adjustment for covariates, survival models showed a moderate but consistent association between preexisting mood (odds ratios [ORs] = 1.3-1.4), anxiety (ORs = 1.2-1.7), and impulse-control disorders (ORs = 1.7-1.9) and the subsequent onset of headache. We also found a dose-response relationship between the number of preexisting mental disorders and subsequent headache onset (OR ranging from 1.9 for 1 preexisting mental disorder to 3.4 for ≥5 preexisting mental disorders). Our findings suggest a consistent and pervasive relationship between a wide range of preexisting mental disorders and the subsequent onset of headaches. This highlights the importance of assessing a broad range of mental disorders, not just depression, as specific risk factors for the subsequent onset of frequent or severe headaches.

PERSPECTIVE

This study shows that there is a temporal association between a broad range of preexisting mental disorders and the subsequent onset of severe or frequent headaches in general population samples across the world.

Mexicans' use of illicit drugs in an era of drug reform: national comparative analysis by migrant status

BACKGROUND

Although rates of illicit drug use are considerably lower in Mexico than in the United States, rates in Mexico have risen significantly. This increase has particular implications for Mexican women and US migrants, who are considered at increased risk of drug use. Due to drug reforms enacted in Mexico in 2008, it is critical to evaluate patterns of drug use among migrants who reside in both regions.

METHODS

We analysed a sample of Mexicans (N=16,249) surveyed during a national household survey in 2011, the Encuesta Nacional de Adicciones (National Survey of Addictions). Comparative analyses based on Mexicans' migrant status - (1) never in the United States, (2) visited the United States, or (3) lived in the United States (transnationals) - featured analysis of variance and Chi-square global tests. Two multilevel regressions were conducted to determine the relationships among migrant status, women, and illicit drug use.

RESULTS

Comparative findings showed significant differences in type and number of drugs used among Mexicans by migrant status. The regression models showed that compared with Mexicans who had never visited the United States, Mexican transnationals were more likely to report having used drugs (OR=2.453, 95% CI=1.933, 3.113) and using more illicit drugs (IRR=2.061, 95% CI=1.626, 2.613). Women were less likely than men to report having used drugs (OR=0.187, 95% CI=0.146, 0.239) and using more illicit drugs (IRR=0.153, 95% CI=0.116, 0.202).

CONCLUSIONS

Overall, the findings support further exploration of risk factors for illicit drug use among Mexican transnationals, who exhibit greater drug use behaviours than Mexicans never in the United States. Because drug reform mandates referrals to treatment for those with recurrent issues of drug use, it is critical for the Mexican government and civic society to develop the capacity to offer evidence-based substance abuse treatment for returning migrants with high-risk drug behaviours.

What data are available on the extent of illicit drug use and dependence globally? Results of four systematic reviews

BACKGROUND

We systematically reviewed availability and quality of data on the prevalence of use and dependence on meth/amphetamine, cannabis, cocaine and opioids.

METHODS

Multiple search strategies: (a) peer-reviewed literature searches (1990-2008) using methods recommended by the Meta-analysis of Observational Studies in Epidemiology (MOOSE) group; (b) systematic searches of online databases; (c) Internet searches to find other published evidence of drug use; (d) repeated consultation and feedback from experts around the globe; (e) a viral email sent to lists of researchers in the illicit drug and HIV fields. Data were extracted and graded according to predefined variables reflecting quality of data source.

RESULTS

Qualitative evidence of illicit drug use and dependence was found for most countries, which hold over 98% of the world's population aged 15-64 years. Countries where use was identified but prevalence estimates had not been made (evidence of drug supply, trafficking, reports of use, treatment data) were mainly from Asia, Africa, the Middle East, and Oceania. Estimates of the prevalence of use were located in 77 countries for meth/amphetamine, 95 for cannabis, 86 for cocaine and 89 for opioids. Dependence prevalence estimates existed in very few countries; 9 meth/amphetamine dependence estimates, 7 cannabis dependence estimates, 5 cocaine dependence estimates, and 25 opioid dependence estimates were located.

CONCLUSIONS

Data on the extent of meth/amphetamine, cannabis, cocaine and opioid use and dependence must be improved in quality and coverage. Dependence estimates are lacking even in high income countries that have required resources. Responses to illicit drug dependence require better estimates of its scale.

Cross-national epidemiology of DSM-IV major depressive episode

BACKGROUND

Major depression is one of the leading causes of disability worldwide, yet epidemiologic data are not available for many countries, particularly low- to middle-income countries. In this paper, we present data on the prevalence, impairment and demographic correlates of depression from 18 high and low- to middle-income countries in the World Mental Health Survey Initiative.

METHODS

Major depressive episodes (MDE) as defined by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DMS-IV) were evaluated in face-to-face interviews using the World Health Organization Composite International Diagnostic Interview (CIDI). Data from 18 countries were analyzed in this report (n = 89,037). All countries surveyed representative, population-based samples of adults.

RESULTS

The average lifetime and 12-month prevalence estimates of DSM-IV MDE were 14.6% and 5.5% in the ten high-income and 11.1% and 5.9% in the eight low- to middle-income countries. The average age of onset ascertained retrospectively was 25.7 in the high-income and 24.0 in low- to middle-income countries. Functional impairment was associated with recency of MDE. The female: male ratio was about 2:1. In high-income countries, younger age was associated with higher 12-month prevalence; by contrast, in several low- to middle-income countries, older age was associated with greater likelihood of MDE. The strongest demographic correlate in high-income countries was being separated from a partner, and in low- to middle-income countries, was being divorced or widowed.

CONCLUSIONS

MDE is a significant public-health concern across all regions of the world and is strongly linked to social conditions. Future research is needed to investigate the combination of demographic risk factors that are most strongly associated with MDE in the specific countries included in the WMH.

Including information about co-morbidity in estimates of disease burden: results from the World Health Organization World Mental Health Surveys

BACKGROUND

The methodology commonly used to estimate disease burden, featuring ratings of severity of individual conditions, has been criticized for ignoring co-morbidity. A methodology that addresses this problem is proposed and illustrated here with data from the World Health Organization World Mental Health Surveys. Although the analysis is based on self-reports about one's own conditions in a community survey, the logic applies equally well to analysis of hypothetical vignettes describing co-morbid condition profiles.

METHOD

Face-to-face interviews in 13 countries (six developing, nine developed; n=31 067; response rate=69.6%) assessed 10 classes of chronic physical and nine of mental conditions. A visual analog scale (VAS) was used to assess overall perceived health. Multiple regression analysis with interactions for co-morbidity was used to estimate associations of conditions with VAS. Simulation was used to estimate condition-specific effects.

RESULTS

The best-fitting model included condition main effects and interactions of types by numbers of conditions. Neurological conditions, insomnia and major depression were rated most severe. Adjustment for co-morbidity reduced condition-specific estimates with substantial between-condition variation (0.24-0.70 ratios of condition-specific estimates with and without adjustment for co-morbidity). The societal-level burden rankings were quite different from the individual-level rankings, with the highest societal-level rankings associated with conditions having high prevalence rather than high individual-level severity.

CONCLUSIONS

Plausible estimates of disorder-specific effects on VAS can be obtained using methods that adjust for co-morbidity. These adjustments substantially influence condition-specific ratings.

The role of criterion A2 in the DSM-IV diagnosis of posttraumatic stress disorder

BACKGROUND

Controversy exists about the utility of DSM-IV posttraumatic stress disorder (PTSD) criterion A2 (A2): that exposure to a potentially traumatic experience (PTE; PTSD criterion A1) is accompanied by intense fear, helplessness, or horror.

METHODS

Lifetime DSM-IV PTSD was assessed with the Composite International Diagnostic Interview in community surveys of 52,826 respondents across 21 countries in the World Mental Health Surveys.

RESULTS

Of 28,490 representative PTEs reported by respondents, 37.6% met criterion A2, a proportion higher than the proportions meeting other criteria (B-F; 5.4%-9.6%). Conditional prevalence of meeting all other criteria for a diagnosis of PTSD given a PTE was significantly higher in the presence (9.7%) than absence (.1%) of A2. However, as only 1.4% of respondents who met all other criteria failed A2, the estimated prevalence of PTSD increased only slightly (from 3.64% to 3.69%) when A2 was not required for diagnosis. Posttraumatic stress disorder with or without criterion A2 did not differ in persistence or predicted consequences (subsequent suicidal ideation or secondary disorders) depending on presence-absence of A2. Furthermore, as A2 was by far the most commonly reported symptom of PTSD, initial assessment of A2 would be much less efficient than screening other criteria in quickly ruling out a large proportion of noncases.

CONCLUSIONS

Removal of A2 from the DSM-IV criterion set would reduce the complexity of diagnosing PTSD, while not substantially increasing the number of people who qualify for diagnosis. Criterion A2 should consequently be reconceptualized as a risk factor for PTSD rather than as a diagnostic requirement.

Early cannabis use and estimated risk of later onset of depression spells: Epidemiologic evidence from the population-based World Health Organization World Mental Health Survey Initiative

Early-onset cannabis use is widespread in many countries and might cause later onset of depression. Sound epidemiologic data across countries are missing. The authors estimated the suspected causal association that links early-onset (age <17 years) cannabis use with later-onset (age > or =17 years) risk of a depression spell, using data on 85,088 subjects from 17 countries participating in the population-based World Health Organization World Mental Health Survey Initiative (2001-2005). In all surveys, multistage household probability samples were evaluated with a fully structured diagnostic interview for assessment of psychiatric conditions. The association between early-onset cannabis use and later risk of a depression spell was studied using conditional logistic regression with local area matching of cases and controls, controlling for sex, age, tobacco use, and other mental health problems. The overall association was modest (controlled for sex and age, risk ratio = 1.5, 95% confidence interval: 1.4, 1.7), was statistically robust in 5 countries, and showed no sex difference. The association did not change appreciably with statistical adjustment for mental health problems, except for childhood conduct problems, which reduced the association to nonsignificance. This study did not allow differentiation of levels of cannabis use; this issue deserves consideration in future research.

Rapid-cycling bipolar disorder: cross-national community study

BACKGROUND

The epidemiology of rapid-cycling bipolar disorder in the community is largely unknown.

AIMS

To investigate the epidemiological characteristics of rapid-cycling and non-rapid-cycling bipolar disorder in a large cross-national community sample.

METHOD

The Composite International Diagnostic Interview (CIDI version 3.0) was used to examine the prevalence, severity, comorbidity, impairment, suicidality, sociodemographics, childhood adversity and treatment of rapid-cycling and non-rapid-cycling bipolar disorder in ten countries (n = 54 257).

RESULTS

The 12-month prevalence of rapid-cycling bipolar disorder was 0.3%. Roughly a third and two-fifths of participants with lifetime and 12-month bipolar disorder respectively met criteria for rapid cycling. Compared with the non-rapid-cycling, rapid-cycling bipolar disorder was associated with younger age at onset, higher persistence, more severe depressive symptoms, greater impairment from depressive symptoms, more out-of-role days from mania/hypomania, more anxiety disorders and an increased likelihood of using health services. Associations regarding childhood, family and other sociodemographic correlates were less clear cut.

CONCLUSIONS

The community epidemiological profile of rapid-cycling bipolar disorder confirms most but not all current clinically based knowledge about the illness.

Smoking estimates from around the world: data from the first 17 participating countries in the World Mental Health Survey Consortium

OBJECTIVE

To contribute new multinational findings on basic descriptive features of smoking and cessation, based upon standardised community surveys of adults residing in seven low-income and middle-income countries and 10 higher-income countries from all regions of the world.

METHODS

Data were collected using standardised interviews and community probability sample survey methods conducted as part of the WHO World Mental Health Surveys Initiative. Demographic and socioeconomic correlates of smoking are studied using cross-tabulation and logistic regression approaches. Within-country sample weights were applied with variance estimation appropriate for complex sample survey designs.

RESULTS

Estimated prevalence of smoking experience (history of ever smoking) and current smoking varied across the countries under study. In all but four countries, one out of every four adults currently smoked. In higher-income countries, estimated proportions of former smokers (those who had quit) were roughly double the corresponding estimates for most low-income and middle-income countries. Characteristics of smokers varied within individual countries, and in relation to the World Bank's low-medium-high gradient of economic development. In stark contrast to a sturdy male-female difference in the uptake of smoking seen in each country, there is no consistent sex-associated pattern in the odds of remaining a smoker (versus quitting).

CONCLUSION

The World Mental Health Surveys estimates complement existing global tobacco monitoring efforts. The observed global diversity of associations with smoking and smoking cessation underscore reasons for implementation of the Framework Convention on Tobacco Control provisions and prompt local adaptation of prevention and control interventions.

Cross-national associations between gender and mental disorders in the World Health Organization World Mental Health Surveys

CONTEXT

Gender differences in mental disorders, including more anxiety and mood disorders among women and more externalizing disorders among men, are found consistently in epidemiological surveys. The gender roles hypothesis suggests that these differences narrow as the roles of women and men become more equal.

OBJECTIVES

To study time-space (cohort-country) variation in gender differences in lifetime DSM-IV mental disorders across cohorts in 15 countries in the World Health Organization World Mental Health Survey Initiative and to determine if this variation is significantly related to time-space variation in female gender role traditionality as measured by aggregate patterns of female education, employment, marital timing, and use of birth control.

DESIGN

Face-to-face household surveys.

SETTING

Africa, the Americas, Asia, Europe, the Middle East, and the Pacific.

PARTICIPANTS

Community-dwelling adults (N = 72,933).

MAIN OUTCOME MEASURES

The World Health Organization Composite International Diagnostic Interview assessed lifetime prevalence and age at onset of 18 DSM-IV anxiety, mood, externalizing, and substance disorders. Survival analyses estimated time-space variation in female to male odds ratios of these disorders across cohorts defined by the following age ranges: 18 to 34, 35 to 49, 50 to 64, and 65 years and older. Structural equation analysis examined predictive effects of variation in gender role traditionality on these odds ratios.

RESULTS

In all cohorts and countries, women had more anxiety and mood disorders than men, and men had more externalizing and substance disorders than women. Although gender differences were generally consistent across cohorts, significant narrowing was found in recent cohorts for major depressive disorder and substance disorders. This narrowing was significantly related to temporal (major depressive disorder) and spatial (substance disorders) variation in gender role traditionality.

CONCLUSIONS

While gender differences in most lifetime mental disorders were fairly stable over the time-space units studied, substantial intercohort narrowing of differences in major depression was found to be related to changes in the traditionality of female gender roles. Additional research is needed to understand why this temporal narrowing was confined to major depression.

Childhood predictors of adult attention-deficit/hyperactivity disorder: results from the World Health Organization World Mental Health Survey Initiative

BACKGROUND

Although it is known that childhood attention-deficit/hyperactivity disorder (ADHD) often persists into adulthood, childhood predictors of this persistence have not been widely studied.

METHODS

Childhood history of ADHD and adult ADHD were assessed in 10 countries in the World Health Organization World Mental Health Surveys. Logistic regression analysis was used to study associations of retrospectively reported childhood risk factors with adult persistence among the 629 adult respondents with childhood ADHD. Risk factors included age; sex; childhood ADHD symptom profiles, severity, and treatment; comorbid child/adolescent DSM-IV disorders; childhood family adversities; and child/adolescent exposure to traumatic events.

RESULTS

An average of 50% of children with ADHD (range: 32.8%-84.1% across countries) continued to meet DSM-IV criteria for ADHD as adults. Persistence was strongly related to childhood ADHD symptom profile (highest persistence associated with the attentional plus impulsive-hyperactive type, odds ratio [OR]=12.4, compared with the lowest associated with the impulsive-hyperactive type), symptom severity (OR=2.0), comorbid major depressive disorder (MDD; OR=2.2), high comorbidity (>or=3 child/adolescent disorders in addition to ADHD; OR=1.7), paternal (but not maternal) anxiety mood disorder (OR=2.4), and parental antisocial personality disorder (OR=2.2). A multivariate risk profile of these variables significantly predicts persistence of ADHD into adulthood (area under the receiving operator characteristic curve=.76).

CONCLUSIONS

A substantial proportion of children with ADHD continue to meet full criteria for ADHD as adults. A multivariate risk index comprising variables that can be assessed in adolescence predicts persistence with good accuracy.

Toward a global view of alcohol, tobacco, cannabis, and cocaine use: findings from the WHO World Mental Health Surveys

BACKGROUND

Alcohol, tobacco, and illegal drug use cause considerable morbidity and mortality, but good cross-national epidemiological data are limited. This paper describes such data from the first 17 countries participating in the World Health Organization's (WHO's) World Mental Health (WMH) Survey Initiative.

METHODS AND FINDINGS

Household surveys with a combined sample size of 85,052 were carried out in the Americas (Colombia, Mexico, United States), Europe (Belgium, France, Germany, Italy, Netherlands, Spain, Ukraine), Middle East and Africa (Israel, Lebanon, Nigeria, South Africa), Asia (Japan, People's Republic of China), and Oceania (New Zealand). The WHO Composite International Diagnostic Interview (CIDI) was used to assess the prevalence and correlates of a wide variety of mental and substance disorders. This paper focuses on lifetime use and age of initiation of tobacco, alcohol, cannabis, and cocaine. Alcohol had been used by most in the Americas, Europe, Japan, and New Zealand, with smaller proportions in the Middle East, Africa, and China. Cannabis use in the US and New Zealand (both 42%) was far higher than in any other country. The US was also an outlier in cocaine use (16%). Males were more likely than females to have used drugs; and a sex-cohort interaction was observed, whereby not only were younger cohorts more likely to use all drugs, but the male-female gap was closing in more recent cohorts. The period of risk for drug initiation also appears to be lengthening longer into adulthood among more recent cohorts. Associations with sociodemographic variables were consistent across countries, as were the curves of incidence of lifetime use.

CONCLUSIONS

Globally, drug use is not distributed evenly and is not simply related to drug policy, since countries with stringent user-level illegal drug policies did not have lower levels of use than countries with liberal ones. Sex differences were consistently documented, but are decreasing in more recent cohorts, who also have higher levels of illegal drug use and extensions in the period of risk for initiation.

Association of alcohol-metabolizing genes with alcoholism in a Mexican Indian (Otomi) population

Association studies provide a powerful approach to link DNA variants and genetic predisposition to complex diseases. In this study, we determined the genotype and allelic frequencies of genes encoding enzymes involved in alcohol metabolism in alcoholic and nonalcoholic subjects of related ethnicity. A total of 118 individuals of Otomi Mexican Indian ancestry were included. Fifty-nine were chronic alcoholics according to WHO criteria and alcohol dependents according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM IV) criteria. They were compared to 59 teetotalers or alcohol consumers of <10 g per day. The restriction fragment length polymorphisms analyzed were ADH1B/MaeIII, ALDH2/MboII, CYP2E1/DraI, CYP2E1/RsaI, and CYP2E1/TaqI. Of the studied polymorphisms, a significant difference between alcoholic and nonalcoholic Otomies was observed only in the CYP2E1/TaqI. The common genotype in alcoholics was A1/A2 (54%), and in nonalcoholics the homozygous A2/A2 (63%) (odds ratio [OR]: 0.28; 95% confidence interval [CI]: 0.13-0.60; P=.002). The frequency of the mutant allele A1 was significantly higher in alcoholics than in nonalcoholics (41 vs. 21%; OR: 2.4; 95% CI: 1.3-4.3; P=.003). This documents the presence of a polymorphism of CYP2E1 that is overexpressed in alcoholic Otomies, in which the variant allele (A1 of CYP2E1/TaqI) is associated with increased susceptibility to alcoholism. The appreciation that this finding may be an additional factor contributing to the high frequency of liver cirrhosis in Otomies requires further investigation.