Dimensions of depression, mania and psychosis in the general population
ABSTRACT 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.
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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. Methods A systematic review of the scientific literature using the PRISMA guidelines. PsychINFO, Cochrane, Scopus, Embase and MEDLINE databases were searched for prospective studies. Results 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. Limitations We were only able to identify a small number of studies of variable quality, thus our conclusions remain preliminary. Conclusions 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.Journal of Affective Disorders 09/2014; 171. DOI:10.1016/j.jad.2014.09.016 · 3.71 Impact Factor
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ABSTRACT: 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.Psychological Medicine 09/2014; 44(12):2557-2566. DOI:10.1017/S0033291714000026 · 5.43 Impact Factor
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ABSTRACT: Psychosis is characterized by a profound lack of trust and disturbed social interactions. Investigating the neural basis of these deficits is difficult because of medication effects but first-degree relatives show qualitatively similar abnormalities to patients with psychosis on various tasks. This study aimed to investigate neural activation in siblings of patients in response to an interactive task. We hypothesized that, compared to controls, siblings would show (i) less basic trust at the beginning of the task and (ii) reduced activation of the brain reward and mentalizing systems.Psychological Medicine 04/2014; 44(16):1-10. DOI:10.1017/S0033291714000737 · 5.43 Impact Factor