In order to investigate whether correlated but separable symptom dimensions that have been identified in clinical samples also have a distribution in the general population, the underlying structure of symptoms of depression, mania and psychosis was studied in a general population sample of 7072 individuals.
Data were obtained from the three measurements of the Netherlands Mental Health Survey and Incidence Study (NEMESIS). Symptoms of depression, mania and the positive symptoms of psychosis were assessed using the Composite International Diagnostic Interview. Confirmatory factor-analysis was used to test statistically the fit of hypothesized models of one, two, three or seven dimensions.
The seven-dimensional model comprising core depression, sleep problems, suicidal thoughts, mania, paranoid delusions, first-rank delusions and hallucinations fitted the data best, whereas the unidimensional model obtained the poorest fit. This pattern of results could be replicated at both follow-up measurements. The results were similar for the subsamples with and without a lifetime DSM-III-R diagnosis. The seven dimensions were moderately to strongly correlated, with correlations ranging from 0.18 to 0.73 (mean 0.45).
In the general population, seven correlated but separable dimensions of experiences exist that resemble dimensions of psychopathology seen in clinical samples with severe mental illness. The substantial correlations between these dimensions in clinical and non-clinical samples may suggest that there is aetiological overlap between the different dimensions regardless of level of severity and diagnosable disorder.
"Thus, the clinical relevance of these findings remains uncertain. Nevertheless, as has been described for sub-threshold psychosis symptoms (Van Os et al., 2009), research suggests that expressions of mania outside the realm of clinical disorder have a distribution in the general population (Akiskal, 2003, Krabbendam et al., 2004) and that sub-threshold expressions of mania show continuity with clinical diagnoses of mania and thus bipolar disorder (Regeer et al., 2006, Thomas, 2004). "
[Show abstract][Hide abstract] ABSTRACT: Background
Whilst cannabis use appears to be a causal risk factor for the development of schizophrenia-related psychosis, associations with mania remain relatively unknown. This review aimed to examine the impact of cannabis use on the incidence of manic symptoms and on their occurrence in those with pre-existing bipolar disorder.
A systematic review of the scientific literature using the PRISMA guidelines. PsychINFO, Cochrane, Scopus, Embase and MEDLINE databases were searched for prospective studies.
Six articles met inclusion criteria. These sampled 2,391 individuals who had experienced mania symptoms. The mean length of follow up was 3.9 years.
Studies support an association between cannabis use and the exacerbation of manic symptoms in those with previously diagnosed bipolar disorder. Furthermore, a meta-analysis of two studies suggests that cannabis use is associated with an approximately 3-fold (Odds Ratio: 2.97; 95% CI: 1.80 to 4.90) increased risk for the new onset of manic symptoms.
We were only able to identify a small number of studies of variable quality, thus our conclusions remain preliminary.
Our findings whilst tentative, suggest that cannabis use may worsen the occurrence of manic symptoms in those diagnosed with bipolar disorder, and may also act as a causal risk factor in the incidence of manic symptoms. This underscores the importance of discouraging cannabis use among youth and those with bipolar disorder to help prevent chronic psychiatric morbidity. More high quality prospective studies are required to fully elucidate how cannabis use may contribute to the development of mania over time.
"nce that ethnicity and markers of sociodemo - graphic adversity were associated with both outcomes , and that female sex was associated with depression but not PEs , the models used do not permit formal testing of whether risk factors are shared , and to a similar extent , across both outcomes or are disorder specific . Similarly , another study ( Krabbendam et al . 2004 ) that examined associations between risk factors and latent constructs of depression and psychosis in the general population did not test whether associations were different across these outcomes , or model these outcomes jointly to allow for the correlation between them . Given the high levels of co - morbidity between depression and "
[Show abstract][Hide abstract] ABSTRACT: Background:
An argument often used to support the view that psychotic experiences (PEs) in general population samples are a valid phenotype for studying the aetiology of schizophrenia is that risk factors for schizophrenia show similar patterns of association with PEs. However, PEs often co-occur with depression, and no study has explicitly tested whether risk factors for schizophrenia are shared between PEs and depression, or are psychopathology specific, while jointly modelling both outcomes.
We used data from 7030 subjects from a birth cohort study. Depression and PEs at age 18 years were assessed using self-report questionnaires and semi-structured interviews. We compared the extent to which risk factors for schizophrenia across sociodemographic, familial, neurodevelopmental, stress-adversity, emotional-behavioural and substance use domains showed different associations with PEs and depression within bivariate models that allowed for their correlation.
Most of the exposures examined were associated, to a similar degree, with an increased risk of both outcomes. However, whereas female sex and family history of depression showed some discrimination as potential risk factors for depression and PEs, with stronger associations in the former, markers of abnormal neurodevelopment showed stronger associations with PEs.
The argument that PEs are valid markers for studying the aetiology of schizophrenia, made simply on the basis that they share risk factors in common, is not well supported. PEs seem to be a weak index of genetic and environmental risk for schizophrenia; however, studies disentangling aetiological pathways to PEs from those impacting upon co-morbid psychopathology might provide important insights into the aetiology of psychotic disorders.
Psychological Medicine 09/2014; 44(12):2557-2566. DOI:10.1017/S0033291714000026 · 5.94 Impact Factor
"In other factor analytic studies with the RC scales (using parcels for each RC scale) typically three or more factors appear with a separate thought dysfunction and externalizing factor (Hoelzle & Meyer, 2008; Sellbom et al., 2008a; Van der Heijden et al., 2012). All of these studies were exclusively patient samples but it is known that psychotic symptoms, although in a lesser degree, have some distribution variance in the general population (Krabbendam et al., 2004; Stefanis et al., 2002). In the current investigation, the psychotic/externalizing factor resembles the psychoticism-impulsive unsocialized sensation-seeking factor in the study of Zuckerman et al. (1988). "
[Show abstract][Hide abstract] ABSTRACT: This study investigates the relationship between personality and psychopathology as measured by the NEO Personality Inventory (Costa & McCrae, 1992) and the Minnesota Multhiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008) in a combined dataset of patients with a broad range of psychiatric disorders (N = 472) and non-patients (N = 323). Results of a joint higher-order factor analysis suggest a positive affectivity and negative affectivity dimension at the top of the structure and a relatively weak integration of (normal) personality and psychopathology in combined factors at different levels of the structural analysis. Openness facets exemplify no relations with psychopathology at any level. Theoretical and clinical implications for the conceptualization and assessment of personality and psychopathology are considered.
Journal of Research in Personality 10/2013; 47(5):572–579. DOI:10.1016/j.jrp.2013.05.001 · 2.00 Impact Factor
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