REVIEW ARTICLE |
Private Practice, Sydney, Australia
Department of Psychiatry, Khyber Medical University, Peshawar, Pakistan
Private Practice, Sydney, and Clinical Research Unit for Anxiety Disorders, School of Psychiatry, University of New South Wales at St Vincent's Hospital, Sydney, Australia
National Drug and Alcohol Research Centre, University of New South Wales, Sydney, Australia
Correspondence: Dr Matthew Large, PO Box 110, Double Bay 1360, NSW, Australia. Email: MMBL{at}bigpond.com
None.
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The duration of untreated psychosis (DUP), the period between the first onset of psychotic symptoms and treatment, has an important influence on the outcome of schizophrenia.
Aims
To compare the published studies of DUP in low- and middle-income (LAMI) countries with the DUP of high-income countries, and examine a possible association between DUP and per capita income.
Method
We used six search strategies to locate studies of the DUP from LAMI countries published between January 1975 and January 2008. We then examined the relationship between DUP and measures of economic activity, which was assessed using the LAMI classification of countries and gross domestic product (GDP) purchasing power parity.
Results
The average mean DUP in studies from LAMI countries was 125.0 weeks compared with 63.4 weeks in studies from high-income countries (P=0.012). Within the studies from LAMI countries, mean DUP fell by 6 weeks for every $1000 of GDP purchasing power parity.
Conclusions
There appears to be an inverse relationship between income and DUP in LAMI countries. The cost of treatment is an impediment to care and subsidised antipsychotic medication would improve the access to treatment and the outcome of psychotic illness in LAMI countries.
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Increasing awareness of the adverse consequences of prolonged DUP in high-income countries has led to calls for a public health approach to early psychosis11 and the introduction of early intervention services. The effect of DUP on the prognosis of psychotic illness in low- and middle-income (LAMI) countries is not known, as there are very few relevant studies. However, long DUP may have more severe consequences in lower-income countries because people who are mentally ill may have increased difficulty obtaining food, shelter and medical care.12,13
The aim of this study was to conduct a systematic review of reports of DUP in LAMI and high-income countries. We used the World Bank classification of `low-income', `lower-middle-income' and `upper-middle-income' economies, referred to together as LAMI countries in this paper, and `high-income' economies (referred to as countries here).14 We also examined the relationship between DUP and the gross domestic product (GDP) purchasing power parity.15
The a priori hypotheses were that (a) DUP would be longer in LAMI countries than high-income countries and (b) DUP would be inversely proportional to per capita income.
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Second, we electronically searched the text of six leading psychiatric journals (Schizophrenia Research, Schizophrenia Bulletin, British Journal of Psychiatry, Acta Psychiatrica Scandinavica, Journal of Clinical Psychiatry and International Clinical Psychopharmacology) that were identified as having published the abstracts of international schizophrenia conference proceedings. Two further studies were located from full text searches using the terms `duration of untreated psychosis' or `DUP' on the journals' websites.
Third, we examined the first 40 results when combining the names of 152 LAMI countries with `duration untreated psychosis' using the search engine Google, which located one further DUP study from a LAMI country.
Fourth, 12 studies from LAMI regions were found using PubMed (from January 1975 to January 2008) by sequentially entering the names of 152 LAMI countries and `schizophrenia', and examining all the abstracts. Publications on movement disorder, gender differences or the epidemiology of schizophrenia were examined in full text.
No further studies were found when hand-searching the references of DUP studies or by contacting 12 authors of recent publications (about aspects of first-episode psychosis in LAMI countries) for unpublished DUP data.
Finally, no additional articles were found by an examination of all the abstracts in electronic databases that specialise in journals from LAMI countries that are not indexed on Medline. The terms `schizophrenia' and `psychosis' were used to search ExtraMED from 1992 to 2000 and LILACS from 1982 to 2008.
All the articles identified by Medline, EMBASE, PsychLit and PsycINFO searches in addition to the articles found from the searches of the six journals were examined in full text by M.L. and O.N. Thirteen differences in the selection of articles were found to be due to instances of the selection of different papers from multiple publications about the same sample and these were resolved by a joint examination of the publications. These searches were cross-checked during the subsequent searches of PubMed and Google by M.L. on two further occasions 3 months apart. One additional article (from a high-income country) was found in the second set of searches (Fig. 1).
![]() View larger version (24K): [in a new window] [as a PowerPoint slide] |
Fig. 1 Flow chart of searches for DUP studies from LAMI and high-income regions.
DUP, duration of untreated psychosis; LAMI, low- and middle-income. (a)
Conventional search strategies including of Medline, EMBASE, PsychLit and
PsycINFO from January 1975 to January 2007, and the text of Schizophrenia
Research, Schizophrenia Bulletin, British Journal of Psychiatry supplements,
Acta Psychiatrica Scandinavica, Journal of Clinical Psychiatry and
International Clinical Psychopharmacology; (b) Google searches of the
first 40 results found after sequentially entering all the names of 152 LAMI
countries combined with `duration untreated psychosis'; (c) PubMed from
January 1975 to January 2008 by sequentially entering the names of 152 LAMI
countries and `schizophrenia', and examining all the abstracts. Publications
on movement disorder, gender differences and the epidemiology of schizophrenia
were examined in full text; (d) LILACS was searched from 1982 to 2008 and
ExtraMED was searched from 1992 to 2000. Hand-searches were performed but
found no additional studies for high-income or LAMI regions.
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No additional assessment of the quality of the data was attempted if the paper met the inclusion criteria, although all but two of the studies from LAMI countries used a recognised diagnostic system.
Forty-four papers reported more than one sample of DUP. All of the samples from different regions or different time frames were used (6 papers), but if a sample was reported in two publications it was only included once. The other reasons for papers reporting more than one sample was to compare participants by gender (17 papers) or diagnosis (13 papers), or more rarely by characteristics such as drug misuse, particular symptom clusters, or the number of subsequent relapses. Papers that dichotomised individuals simply on the basis of the DUP were included as a single sample.
The following data were collected from all of the samples:
Data extraction
The data from studies from LAMI countries were independently extracted by
M.L. and S.F. and from high-income countries by M.L. and O.N. Three
differences in the DUP data collection in both the LAMI and high-income
samples were unambiguously resolved by further examination. A check of the
reliability of the rating of the inclusion of patients with
schizophrenia-related psychosis was performed and was found to have a kappa of
1, as no differences were found. A final masked check of the electronic record
of all the data points was conducted by M.L. 6 months after the initial data
extraction. This found five minor errors in age at onset and gender that were
probably owing to errors in transcription.
Definitions of psychotic illness
All but five studies used a recognised diagnostic system but there were
differences in the way psychotic disorders were classified and reported. Some
publications only reported the numbers of patients with the diagnoses
schizophrenia, bipolar disorder and psychotic depression, whereas other
studies reported the proportion of people with other schizophrenia-related
psychoses such as delusional disorder and psychosis not otherwise specified.
All the studies stated whether they included patients with affective
psychosis, but the proportion of people who were diagnosed with schizophrenia
was not available for every sample. As patients with affective psychosis are
known to have a shorter DUP than those with schizophrenia-related psychosis
(defined as any functional psychosis other than bipolar disorder and psychotic
depression) the characteristics of samples of patients with
schizophreniarelated psychosis was also analysed. Schizoaffective disorder was
included in our definition of schizophrenia-related psychosis.
Definition of duration of untreated psychosis
Duration of untreated psychosis has been defined as the period between the
onset of definite psychotic symptoms and the beginning of adequate
treatment.16 We
included all the definitions of what is considered to be the end of DUP,
including the initiation of treatment, the end of adequate treatment and
contact with mental health services. Contact with researchers was also
accepted as an endpoint of DUP in studies from LAMI countries as there were so
few studies. The inclusion of individuals who only had contact with
researchers rather than mental health services would be likely to increase the
estimates of mean DUP for LAMI countries given the greater likelihood of
undetected DUP being prolonged. Conversely, inclusion of individuals with
affective psychosis would be expected to decrease mean DUP. In an effort to
counter these potential confounders, we examined a subset of studies of
patients in LAMI countries with schizophrenia-related psychoses, who were
recruited as a result of contact with mental health services and had at least
some treatment, to allow a comparison with similar studies conducted in
high-income countries.
Income data
The LAMI country classification is based on per capita GDP in international
dollars. However, comparing income between countries in terms of official
exchange rates may not reflect the local cost of goods and services. Therefore
we also examined the relationship between DUP and GDP purchasing power
parity.
Statistical methods
Consideration was given to the use of meta-regression in order to take the
degree of variability of the studies into account. However, meta-analysis
requires a measure of the variability of the mean such as the standard
deviation. After emailing the authors of studies from LAMI countries who did
not report the standard deviation of the mean DUP, only 32 of the 41 data
points had a standard deviation. Moreover, the average mean DUP of studies
from LAMI regions that did not report the standard deviation was 88 weeks and
was significantly shorter than the average mean of 138 weeks of studies for
which a standard deviation was available. Hence, the exclusion of these
studies would have biased our study in favour of finding a prolonged DUP in
studies from LAMI countries. Instead, the samples were weighted for regression
analysis by the number of participants, as larger samples would be expected to
have a more accurate figure for mean DUP.
The degree of variation between mean DUP values was also considered, as mean and median DUP values were significantly skewed. In order to avoid statistical findings that were unduly influenced by samples with a very long DUP, the DUP values were log10 transformed for both the univariate comparisons of the DUP in LAMI and high-income regions, and a multiple linear regression analysis of factors associated with the mean DUP. The distributions of mean DUP values were not significantly skewed after log10 transformation.
Chi-squared tests were used to compare the proportions of male participants, the number of participants with a schizophrenia-related psychosis and the number of participants diagnosed with schizophrenia in LAMI v. high-income groups. The age at onset was calculated by subtracting DUP from age at presentation and was used in preference to age at presentation because it is independent of DUP. Ages were compared using a two-tailed Student's t-test.
A multiple linear regression model was used to examine the associations between the dependent variable of log10 DUP and high-income v. LAMI status and the covariables of age, gender and the inclusion of patients diagnosed with affective psychosis.
A linear regression model using untransformed data was used to examine the relationship between DUP and GDP purchasing power parity within LAMI regions after a scattergram showed an apparently linear relationship between these two variables. Four studies of patients who came into contact with researchers but did not necessarily receive treatment were excluded from this analysis because their DUP was much longer (mean DUP >5 years) than in other samples. The remaining samples were not significantly skewed.
All statistical tests were two-tailed and results were regarded as statistically significant at or below the 5% probability level. The statistical analysis was performed using SPSS for Windows, version 15.0.
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There were 98 studies that met the inclusion criteria, of which 23 (26 papers) were from LAMI countries17–42 (see online Table DS1) and 75 were from high-income countries (Table DS2). The earliest study from a LAMI country was published in 1995. The 23 studies from LAMI countries included 24 samples in which DUP was reported directly and 17 samples in which mean DUP could be calculated; hence, in total there were 41 samples of DUP for patients from LAMI countries. All but 3 studies were published in full text in peer-reviewed journals. We contacted 13 authors to clarify some data points and 2 authors provided some additional information about their research that had been published in abstract form.21,38 Twenty-seven samples from LAMI countries reported the interval between the onset of psychosis and contact with services in patients with schizophrenia-related psychosis.
All the studies from high-income countries appeared in full text in peer-reviewed journals and all but eight studies were published after 1990. Mean DUP was reported directly for 88 samples, and in a further 19 samples mean DUP could be calculated by subtracting the mean age at onset from the mean age at presentation.
Results of the study
The weighted mean, average mean DUP and the median mean DUP were
significantly longer in studies from LAMI countries than in studies from
high-income countries. The average median DUP was longer in studies from LAMI
countries than from high-income countries but the apparently large difference
did not reach statistical significance, probably because of the small number
of samples from LAMI regions and because of relatively large within-group
variability in median DUP (Table
1).
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View this table: [in a new window] |
Table 1 Duration of untreated psychosis, diagnostic and demographic variables in
the LAMI groups
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The longer average mean DUP in studies from LAMI countries was a result of a prolonged DUP in low-income and lower-middle-income countries, as the average mean DUP in the studies from upper-middle-income countries was shorter than that of high-income countries (Table 1). Mean age at onset and mean age at presentation were higher in samples from LAMI countries than high-income countries. Studies from LAMI countries had fewer male participants but slightly more participants diagnosed with a schizophrenia-related psychosis. In the LAMI group, more patients who were diagnosed with a schizophrenia-related psychosis were considered to have a diagnosis of schizophrenia or schizophreniform disorder.
We examined a subset of studies of individuals with schizophrenia-related psychosis who had received some treatment. The mean DUP in the samples from LAMI countries (85.2 weeks, s.d.=38.3, 95% CI 70.0–100.3, n=27) was significantly longer that the mean DUP in samples from high-income countries (70.5 weeks, s.d.=55.3, 95% CI 57.8–83.1, n=76, unpaired t-test. LAMI v. high-income d.f.=101, t=2.05, two-tailed P=0.04, using log10 transformed mean DUP values). This confirmed that the difference between the mean DUP of LAMI countries and high-income countries was not due to the proportion of participants with affective psychoses in high-income countries or the proportion of participants who did not receive treatment in LAMI countries.
The univariate finding of a longer mean DUP was confirmed with a multiple linear regression (using log10 mean DUP as the dependent variable and weighted for the number of people in each sample) that found that the association between longer DUP and samples from LAMI countries was independent of inclusion of samples with patients whose diagnosis was affective psychosis. The proportion of males in the samples and age at onset were not significantly associated with log10 mean DUP (model summary: r=0.462, r2=0.214, standard error of the estimate=2.92) (Table DS3).
Relationship between gross domestic product and mean duration of untreated psychosis
We examined the hypothesised relationship between GDP purchasing power
parity and mean DUP in LAMI countries using linear regression. For every $1000
of additional per capita GDP purchasing power parity, mean DUP fell by 6 weeks
(model summary: r=0.497, r2=0.247, standard error
of the estimate= 296.3) (Table DS4). An analysis of the mean DUP in the
samples of patients with schizophrenia-related psychosis suggested a fall of 9
weeks of DUP per $1000 of per capita GDP purchasing power parity (model
summary: r=0.644, r2=0.415, standard error of the
estimate=268.1) (Table DS5). No significant relationship between median DUP
and GDP was found, possibly because so few studies from low-income and
lower-middle-income countries reported a figure for median DUP (n=10;
Table 1).
A surprising finding was that mean DUP rose by 3 weeks per $1000 of GDP purchasing power parity in studies from high-income countries (r=0.243, r2=0.059, d.f.=106, GDP purchasing power parity coefficients: B=0.003, s.e.=0.001, t=2.567, P=0.012). This rise was associated with studies from regions with mental health laws that required the patient to be assessed as dangerous before they could receive involuntary treatment.43 Mean DUP was not associated with GDP purchasing power parity in high-income countries when the presence of this form of mental health law was included in the model.
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Long DUP in LAMI countries may be associated with low income
The hypothesis that DUP is longer in LAMI countries was confirmed. We also
found a linear relationship between GDP purchasing power parity and DUP in
LAMI countries and this raises the possibility of a causal relationship
between low income and treatment delay. However, this finding is qualified as
the DUP in the small number of studies from upper-middle-income countries was
shorter than the average mean DUP of high-income countries.
Long DUP in high-income countries is usually attributed to lack of insight on the part of the patient, the gradual onset of psychosis in some patients and the families' lack of understanding of the need for treatment. The reasons for longer DUP in LAMI countries warrants further investigation, but is likely to include the lack of services in many areas as well as the cost of treatment.
The cost of treatment is frequently reported as a barrier to care in low-income21,36,37,39 and lower-middle-income40,45,46 countries. For example, in a region of Nigeria the only available antipsychotic was a low dose of chlorpromazine for a few weeks per year provided by a charity.45 In India, the direct cost of treating schizophrenia is a quarter of the average family income in dollars.46 Even if the patient's family were able to purchase some antipsychotic medication it could be at the expense of other forms of essential medical care or even food. Hence, it is not surprising that mean DUP declined with even modest increases in income.
Better prognosis in LAMI countries with long DUP?
The relationship of DUP to outcome in LAMI countries has not been
extensively investigated. Although it is widely believed that the prognosis of
schizophrenia is better in LAMI
countries,47 we
found a number of studies reporting a worse outcome in these regions. For
example, both treated and untreated patients from Morocco were less likely to
be employed than a similar sample from the
USA,48 and in rural
China where very few patients received adequate treatment, untreated patients
were found to have marked social and occupational disability and a fourfold
increase in
mortality.36,37,49
Another study from the Indonesian Island of Bali reported an association
between long DUP and increased mortality in the decade after contact with
services.28 In Bali
and in rural China the excess mortality was not from suicide, but from a lack
of physical
care.28,49
Our finding of a very long DUP in low-income and lower-middle-income
countries, and other studies that found large numbers of patients who had
never received treatment, raises the possibility that a subset of patients
with long DUP in some outcome studies either died or were lost to follow-up
for other reasons.
Subsidised psychiatric treatment may shorten DUP
This study has highlighted the initial delay in receiving treatment in LAMI
countries. The overall treatment gap may be greater, as there are studies from
LAMI countries that describe large numbers of patients who never receive any
treatment.32,36,37,45
Worldwide, schizophrenia is the eighth largest cause of disability and the illness may shorten life expectancy by 10 years.50 The direct effects of schizophrenia are comparable to those of many infectious and chronic physical illnesses that receive more funding for both treatment and research. Cost-effective treatment is now available for schizophrenia. A public health initiative to subsidise antipsychotic medication for the critical first 2 years of psychotic illness could greatly improve outcome for psychotic illness worldwide.51 Combining subsidised mental health services with other forms of primary healthcare, as reported from Zambia, a low-income country where the DUP was comparatively short,31 could also significantly reduce the delay in treatment and improve the prognosis of mental illness in poorer countries.
Patients with psychosis in low-income and lower-middle-income countries may be among the most disadvantaged people on earth and providing them with access to basic treatment would be a cost-effective public health measure.
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39: 859-68.[Medline]Related articles in BJP:
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