Rob V. Bijl

Strauss (1969) revisited: a psychosis continuum in the general population?

Although dichotomously defined for clinical purposes, psychosis may exist as a continuous phenotype in nature. A random sample of 7076 men and women aged 18-64years were interviewed by trained lay interviewers with the Composite International Diagnostic Interview (CIDI). Those with evidence of psychosis according to the CIDI were additionally interviewed by psychiatrists. For the 17 CIDI core psychosis items, we compared a psychiatrists rating of hallucinations and/or delusions (Clinical Psychosis; sample prevalence 4.2%) with three other possible positive CIDI ratings of the same items: (i) symptom present, but not clinically relevant (NCR Symptom; sample prevalence 12.9%); (ii) symptom present, but the result of drugs or somatic disorder (Secondary Symptom; sample prevalence 0.6%); (iii) symptom appears present, but there is a plausible explanation (Plausible Symptom; sample prevalence 4.0%). Of the 1237 individuals with any type of positive psychosis rating (sample prevalence 17.5%), only 26 (2.1%) had a DSM-III-R diagnosis of non-affective psychosis. All the different types of psychosis ratings were strongly associated with the presence of psychiatrist-rated Clinical Psychosis (NCR Symptom: OR=3.4; 95% CI: 2.9-3.9; Secondary Symptom: OR=4.5; 95% CI: 2.7-7.7; Plausible Symptom: OR=5.8; 95% CI: 4.7-7.1). Associations with lower age, single marital status, urban dwelling, lower level of education, lower quality of life, depressive symptoms and blunting of affect did not differ qualitatively as a function of type of rating of the psychotic symptom, were similar in individuals with and without any CIDI lifetime diagnosis, and closely resembled those previously reported for schizophrenia. Presence of any rating of hallucinations was strongly associated with any rating of delusions (OR=6.7; 95% CI: 5.6-8.1), regardless of presence of any CIDI lifetime diagnosis. The observation by Strauss (1969. Hallucinations and delusions as points on continua function. Arch. Gen. Psychiatry 21, 581-586) that dichotomously diagnosed psychotic symptoms in clinical samples are, in fact, part of a continuum of experiences, may also apply to the general population. The boundaries of the psychosis phenotype may extend beyond the clinical concept of schizophrenia.

Comorbidity of substance use disorders with mood and anxiety disorders: Results of the international consortium in psychiatric epidemiology

This article reports the results of a cross-national investigation of patterns of comorbidity between substance use and psychiatric disorders in six studies participating in the International Consortium in Psychiatric Epidemiology. In general, there was a strong association between mood and anxiety disorders as well as conduct and antisocial personality disorder with substance disorders at all sites. The results also suggest that there is a continuum in the magnitude of comorbidity as a function of the spectrum of substance use category (use, problems, dependence), as well as a direct relationship between the number of comorbid disorders and increasing levels of severity of substance use disorders (which was particularly pronounced for drugs). Finally, whereas there was no specific temporal pattern of onset for mood disorders in relation to substance disorders, the onset of anxiety disorders was more likely to precede that of substance disorders in all countries. These results illustrate the contribution of cross-national data to understanding the patterns and risk factors for psychopathology and substance use disorders.

Bipolar disorder in the general population in The Netherlands (prevalence, consequences and care utilisation): results from The Netherlands Mental Health Survey and Incidence Study (NEMESIS)

BACKGROUND Little is known about the prevalence of bipolar disorder in the general population, what proportion is receiving care and what factors motivate people to seek help. METHOD Data were derived from The Netherlands Mental Health Survey and Incidence Study (NEMESIS), a psychiatric epidemiological study in the general population in The Netherlands. DSM-III-R diagnoses were based on the Composite International Diagnostic Interview (CIDI). RESULTS Lifetime prevalence of bipolar disorder was 1.9%. Compared to other mental disorders, people with bipolar disorder were more often incapacitated were more likely to have attempted suicide and reported a poorer quality of life 82.8% had experienced an additional mental disorder in their lifetime; 25.5% had never sought help for their emotional problems, not even primary, informal or alternative care. LIMITATIONS Three limitations of the study are: (1) the CIDI prevalence estimates for bipolar disorder may be inflated; (2) personality disorders were not recorded in the NEMESIS dataset; (3) in NEMESIS certain groups have not been reached. CONCLUSION Three-quarters of the bipolar respondents do not benefit sufficiently from the treatment methods now available. In view of the serious consequences of this condition, greater efforts are needed to reach people with bipolar disorder, to get them into treatment.

Prevalence and age of onset for drug use in seven international sites: results from the international consortium of psychiatric epidemiology

This study compares lifetime prevalence and age of first use (onset) for alcohol, cannabis, and other drugs in six international sites. Data from seven epidemiologic field surveys that used compatible instruments and study designs were compiled for cross-site analyses by the International Consortium of Psychiatric Epidemiology (ICPE). The world health organizations composite international diagnostic instrument (WHO-CIDI) and additional items were used to ascertain drug use in each site. Lifetime use rates were estimated for alcohol, cannabis, and other illicit drugs. Survival analyses were used to estimate age of onset. Study settings and main results: use of alcohol twelve or more times ranged in descending order from the Netherlands (86.3%), United States (71.7%), Ontario, Canada (71.6%); São Paulo, Brazil (66.1%), Munich, Germany (64.9%), Fresno, California (USA) (51.9%), to Mexico City (43.2%). Use of cannabis five or more times in a lifetime ranged from 28.8 in the United States to 1.7% in Mexico City, and other drugs ranged from United States (19.4%) to Mexico City (1.7%). Age of first use was similar across study sites. This study demonstrates the fundamental uniformity of onset patterns by age as contrasted with wide variations in lifetime prevalences across sites. Study findings suggest that drug use patterns may change among emigrating populations from low consumption nations as a consequence of international resettlement in nations with higher rates. Methodological limitations of the study along with recommendations for future international comparative research are discussed.

Neuroticism and low self-esteem as risk factors for psychosis

Background Low self-esteem and high neuroticism are common features in psychosis, but in the absence of longitudinal studies it is unclear whether they represent consequences of the illness or risk factors acting before illness onset. Methods A population sample of 3,929 individuals with no lifetime evidence of psychosis were interviewed with the Composite International Diagnostic Interview and were administered the Groningen Neuroticism Scale and the Rosenberg Self-Esteem Scale at baseline and 1 and 3 years later. At year 3, individuals with CIDI evidence of psychotic symptoms were interviewed by clinicians to identify incident psychotic or psychosis-like symptoms. Results Baseline neuroticism and self-esteem predicted first-ever onset of psychotic symptoms at year 3 (neuroticism, OR 1.16, 95 % CI 1.09, 1.23; self-esteem, OR 1.09, 95 % CI 1.01, 1.18). When adjusted for each other and for level of anxiety and depression, neuroticism was the strongest independent predictor for onset of psychotic symptoms (OR 1.16, 95 % CI 1.07, 1.26). Conclusions Neuroticism increases the risk for development of psychotic symptoms. Mechanisms of risk may involve certain cognitive styles associated with neuroticism, such as beliefs about the uncontrollability of certain events and experiences. The association between low self-esteem and psychosis may involve the area of overlap between self-esteem and neuroticism.

Predictors of first incidence of DSM-III-R psychiatric disorders in the general population: findings from the Netherlands Mental Health Survey and Incidence Study.

de Graaf R, Bijl RV, Ravelli A, Smit F, Vollebergh WAM. Predictors of first incidence of DSM‐III‐R psychiatric disorders in the general population: findings from the Netherlands Mental Health Survey and Incidence Study. Acta Psychiatr Scand 2002: 106: 303–313.

Temporal sequencing of lifetime mood disorders in relation to comorbid anxiety and substance use disorders - Findings from the Netherlands Mental Health Survey and Incidence Study

Abstract.Background: Little is known about the temporal sequencing of psychiatric disorders. The aim of this study was to obtain insight into patterns of co-occurrence of DSM-III-R mood disorders in relation to anxiety and substance use disorders, their temporal sequencing and the sociodemographic and long-term vulnerability predictors of this temporal sequencing. Methods: Data are from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a psychiatric epidemiological study in a representative sample of 7,076 adults aged 18–64. Results: Of those who had ever experienced a mood disorder, 46 % of males and 57 % of females had a history of anxiety disorders, and 43 % and 15 % of substance use disorders. Mood disorders were associated with all anxiety and substance use disorders, except with alcohol abuse among males. In the majority of anxiety-comorbid cases, the mood disorder arose after the anxiety disorder; the pattern for substance use-comorbid disorders was more variable. Deviation from the usual sequence of major depression and anxiety disorders was more often seen among females, subjects with a higher educational level, subjects who experienced childhood parental divorce, and subjects who experienced childhood emotional neglect. Conclusions: When comorbid with anxiety disorders, mood disorders clearly tend to be secondary. Few of the studied demographic factors, familial vulnerability factors and childhood life events predict the sequencing of mood disorders in relation to other disorders.

Gender and age-specific first incidence of DSM-III-R psychiatric disorders in the general population. Results from the Netherlands Mental Health Survey and Incidence Study (NEMESIS).

Background Prospective studies in the general population are needed to identify risk factors for mental disorders. Samples of sufficient size are needed, but large-scale studies that assess the incidence of psychopathology are rare. Aims The aim of this study was to investigate the 12-month first incidence rates (IR) by age and gender for 15 specified DSM-III-R disorders in the general population. Methods The study was based on a representative sample (N = 5618) of the Dutch population aged 18–64. Results The IR for any disorder was 5.68 per 100 person-years at risk (men 4.45, women 6.94). IRs for both men and women were highest in the youngest age category. The most common 12-month incident disorders in men were alcohol abuse (IR = 4.09) and major depression (1.72). In women, the most common incident disorders were major depression (IR = 3.90) and simple phobia (3.17). Conclusions The results show the rarity of first-onset of mental disorders. IRs vary strongly between the different life phases, as well as between men and women. This suggests potential target areas for age-specific and gender-specific prevention.

Determinants of poor 1‐year outcome of DSM‐III‐R major depression in the general population: results of the Netherlands Mental Health Survey and Incidence Study (NEMESIS)

Objective:  To investigate risk factors of poor 1‐year outcome of major depression in the general population and to compare the results with data from clinical populations.

Self‐reported psychotic experiences in the general population: a valid screening tool for DSM‐III‐R psychotic disorders?

Objective:   To examine the diagnostic value of self‐reported psychotic‐like experiences for DSM‐III‐R psychotic disorders.