Exposure to conflict and disaster: A national survey on the prevalence of psychotic experiences in Sri Lanka
Introduction
Substantial evidence has accumulated that low-level psychotic experiences, such as fleeting and non-distressing hallucinations, strange experiences and delusions, are common in the general population (Johns and van Os, 2001). Findings from large population surveys suggest that the prevalence of psychotic experiences (PE) ranges from 5%–20% (Verdoux and van Os, 2002, Johns et al., 2004, King et al., 2005, Scott et al., 2006, Morgan et al., 2009). Further, in a considerable proportion of individuals, subclinical PE persist over time, which, in turn, is associated with an increased risk of psychotic disorder (Linscott and van Os, 2013). There is also evidence that socio-environmental risk factors are shared across PE and psychotic disorder (Morgan et al., 2009).
To date, most research on PE has come from high-income countries, with only a small number of studies conducted in low- and middle-income countries (LMICs) (Soosay et al., 2012). The reported prevalence in LMICs ranges from 4% in Tanzania (Jenkins et al., 2010) to 12% in Timor Leste (Soosay et al., 2012). An even greater variation in prevalence (0.8%–31.4%) was found in the WHO cross-national World Health Survey conducted in 52 countries (Nuevo et al., 2012), which reported a prevalence of PE of only 2.4% in Sri Lanka. Studies investigating this issue in LMICs are frequently beset by methodological shortcomings, such as having a representative sample and small sample size, which may account for variation in the prevalence of PE reported to date.
Several factors have been shown to be associated with PE (Spauwen et al., 2006, Campbell and Morrison, 2007, Hides et al., 2009). However, only a small number of studies have examined the role of exposure to trauma of armed conflict in relation to PE (Soosay et al., 2012, Amone-P'olak et al., 2013, Lindley et al., 2014). Exposure to natural disasters may increase risk of developing a mental disorder (Meewisse et al., 2011, Ekanayake et al., 2013, Dorrington et al., 2014), but no study that we are aware of has investigated the association between natural disasters and PE.
Sri Lanka is one of the few countries that simultaneously faced war and natural disaster, in which the relative impact of each can be compared and studied in relation to psychosis. The country has experienced three armed conflicts that have arisen out of ethnic tensions (Siriwardhana and Wickramage, 2014). It is estimated that up to 70,000 people died as a consequence of the most recent conflict between the majority Sinhalese and minority Tamil population and many thousands more were displaced (Siriwardhana et al., 2013a, Siriwardhana and Wickramage, 2014). In addition, Sri Lanka was hit by a tsunami on 26th December 2004, devastating almost two thirds of the island's coastline and resulting in an estimated death toll of 40,000 (Siriwardhana et al., 2012). Against this background, we sought to investigate the association between PE and exposure to traumatic events of prolonged conflict and a devastating natural disaster in a large community-based sample. Specifically, our aims were to: 1) estimate the prevalence of PE in the Sri Lankan population; and 2) assess whether a) exposure to conflict-related traumatic events and/or b) exposure to tsunami-related traumatic events were associated with a higher prevalence of PE.
Section snippets
Method
The National Mental Health Survey was a community based cross-sectional survey in Sri Lanka. Full details of the methods used are provided in previous reports (Institute for Research and Development, 2007).
Prevalence of PE
A total of 6120 participants were successfully recruited for the survey. Of these, 5927 participants completed the PSQ and were included in the analyses. The 193 participants who did not take part were more likely to be women (65.3% vs 34.7%, p < 0.001) and from younger age group (37.4%, p = 0.015). Of the 5927 participants who completed the PSQ, 572 endorsed at least one of the secondary questions. This yielded a weighted prevalence of PE of 9.7%. The most commonly endorsed secondary question was
Discussion
This is the first study to investigate the population prevalence of PE in the Sri Lankan population, and associations with conflict- and tsunami-related trauma. This yielded a prevalence of PE of 9.7% in a national sample in Sri Lanka. There was also evidence that exposure to conflict-related trauma is associated with PE. Specifically, PE were more common in individuals who reported loss or injury of family or friends; and cumulative exposure to one or more conflict-related traumatic events as
Conclusions
Findings from this study support the hypothesis that cumulative exposure to conflict-related trauma and exposure to specific traumatic events of natural disasters are associated with a higher prevalence of PE. They are consistent with the proposition that PE are common in the general population. Given PE can be distressing and may contribute to the development of diagnosable psychotic disorder (DeVylder et al., 2014), these findings are important in that they provide prevalence estimates of PE
Conflict of interest
All authors declare that they have no conflicts of interest.
Contributors
AS and CS contributed to conception and design of the study. AH and UR analysed the data and jointly drafted the article with CM. All authors contributed to interpretation of data, revised the article for important intellectual content, and provided approval of the version to be published.
Role of funding source
UR is supported by funding from a Postdoctoral Research Fellowship of the UK National Institute of Health Research (grant no. NIHR-PDF-201104065) and a Veni grant from the Netherlands Organisation for Scientific Research (grant no. 451-13-022). This Sri Lankan study was funded by the Sri Lanka Health Sector Development Project of the World Bank.
Acknowledgements
We would like to thank Suwin Hewage, Samantha Wijesingha who executed the study; Sudath Samarawera, Sisira Siribaddana who were involved in designing the National Mental Health Survey. We would also like to thank the Institute for Research and Development, which carried out the study; Officials of the Ministry of Health and all study participants for their contributions.
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