Article

Is the incidence of psychotic disorder in decline? Epidemiological evidence from two decades of research

Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK.
International Journal of Epidemiology (Impact Factor: 9.2). 09/2008; 38(5):1255-64. DOI: 10.1093/ije/dyn168
Source: PubMed

ABSTRACT It is unclear whether the incidence of first episode psychoses is in decline. We had the opportunity to determine whether incidence had changed over a 20-year period in a single setting, and test whether this could be explained by demographic or clinical changes.
The entire population at-risk aged 16-54 in Nottingham over three time periods (1978-80, 1993-95 and 1997-99) were followed up. All participants presenting with an ICD-9/10 first episode psychosis were included. The remainder of the population at-risk formed the denominator. Standardized incidence rates were calculated at each time period with possible change over time assessed via Poisson regression. We studied six outcomes: substance-induced psychoses, schizophrenia, other non-affective psychoses, manic psychoses, depressive psychoses and all psychotic disorders combined.
Three hundred and forty-seven participants with a first episode psychosis during 1.2 million person-years of follow-up over three time periods were identified. The incidence of non-affective or affective psychoses had not changed over time following standardization for age, sex and ethnicity. We observed a linear increase in the incidence of substance-induced psychosis, per annum, over time (incidence rate ratios: 1.15; 95% CI 1.05-1.25). This could not be explained by longitudinal changes in the age, sex and ethnic structure of the population at-risk.
Our findings suggest psychotic disorders are not in decline, though there has been a change in the syndromal presentation of non-affective disorders, away from schizophrenia towards other non-affective psychoses. The incidence of substance-induced psychosis has increased, consistent with increases in substance toxicity over time, rather than changes in the prevalence or vulnerability to substance misuse. Increased clinical and popular awareness of substance misuse could also not be excluded.

Download full-text

Full-text

Available from: Peter Jones, Jan 13, 2014
0 Followers
 · 
114 Views
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Substitute “schizophrenia and other psychoses” for “social failure and success” and the relevancy of JBS Haldane’s quote to the search for the causes of psychotic disorders becomes immediately apparent. If we accept Tim Crow’s powerful assertion that psychosis is the price Homo sapiens pay for language (Crow 2000) then there shall be no requirement to bastardise the quote at all.
    12/2009: pages 67-96;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ten years ago, during the “IV Search for the Causes of Schizophrenia” meeting, one of the main issues regarding the epidemiology of schizophrenia was the meaning and implications of universality and uniformity in incidence rates for the disease in different places and cultures (Jablensky 1999; Eaton 1999). Most of the evidence upon which the interpretation of data and conclusions were based came from the “Ten Country Study”, coordinated by the World Health Organization (WHO) (Sartorius et al. 1986; Jablensky et al. 1992). In that study, also known as the “Determinants of Severe Mental Disorder” study (DOSMeD), incidence rate estimates were obtained for 8 of the 12 participating centres, two of which were from Chandigarh (urban and rural areas), in India. The study also generated relevant data on the outcome of schizophrenia in different cultures. Interpretation of the results from the “Ten Country Study” led to the widespread beliefs that the incidence of schizophrenia is similar across populations and cultures and that its prognosis is more favourable for persons who live in low- and middle-income countries (LAMICs) compared to those living in high-income countries, notions that can be seen in recent publications in the most prestigious scientific medical journals (e.g. Mueser and McGurk 2004).
    12/2009: pages 3-17;
Show more