Prevalence of post-Traumatic stress disorder and validity of the Impact of Events Scale-Revised in primary care in Zimbabwe, a non-war-Affected African country

Melanie A. Abas; Monika Müller; Lorna J. Gibson; Sarah Derveeuw; Nirosha Dissanayake; Patrick Smith; Ruth Verhey; Andrea Danese; Dixon Chibanda

doi:10.1192/bjo.2022.621

Prevalence of post-Traumatic stress disorder and validity of the Impact of Events Scale-Revised in primary care in Zimbabwe, a non-war-Affected African country

Melanie A. Abas, Monika Müller^*, Lorna J. Gibson, Sarah Derveeuw, Nirosha Dissanayake, Patrick Smith, Ruth Verhey, Andrea Danese, Dixon Chibanda

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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Abstract

Background A critical step in research on the epidemiology of post-Traumatic stress disorder (PTSD) in low-resource settings is the validation of brief self-reported psychometric tools available in the public domain, such as the Impact Event Scale-Revised (IES-R). Aims We aimed to investigate the validity of the IES-R in a primary healthcare setting in Harare, Zimbabwe. Method We analysed data from a survey of 264 consecutively sampled adults (mean age 38 years; 78% female). We estimated the area under the receiver operating characteristic curve and sensitivity, specificity and likelihood ratios for different cut-off points of the IES-R, against a diagnosis of PTSD made using the Structured Clinical Interview for DSM-IV. We performed factor analysis to evaluate construct validity of the IES-R. Results The prevalence of PTSD was 23.9% (95% CI 18.9-29.5). The area under the curve for the IES-R was 0.90. At a cut-off of ≥47, the sensitivity of the IES-R to detect PTSD was 84.1 (95% CI 72.7-92.1) and specificity was 81.1 (95% CI 75.0-86.3). Positive and negative likelihood ratios were 4.45 and 0.20, respectively. Factor analysis revealed a two-factor solution, with both factors showing good internal consistency (Cronbach's factor-1 α = 0.95, factor-2 α = 0.76). In a post hoc analysis, we found the brief six-item IES-6 also performed well, with an area under the curve of 0.87 and optimal cut-off of 15. Conclusions The IES-R and IES-6 had good psychometric properties and performed well for indicating possible PTSD, but at higher cut-off points than those recommended in the Global North.

Original language	English
Article number	e37
Journal	BJPsych Open
Volume	9
Issue number	2
DOIs	https://doi.org/10.1192/bjo.2022.621
Publication status	Published - 16 Mar 2023

Keywords

Global mental health
low-and middle-income countries
post-Traumatic stress disorder
psychological testing
rating scales

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1192/bjo.2022.621

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@article{4b3e804714d7426798194f00220390ef,

title = "Prevalence of post-Traumatic stress disorder and validity of the Impact of Events Scale-Revised in primary care in Zimbabwe, a non-war-Affected African country",

abstract = "Background A critical step in research on the epidemiology of post-Traumatic stress disorder (PTSD) in low-resource settings is the validation of brief self-reported psychometric tools available in the public domain, such as the Impact Event Scale-Revised (IES-R). Aims We aimed to investigate the validity of the IES-R in a primary healthcare setting in Harare, Zimbabwe. Method We analysed data from a survey of 264 consecutively sampled adults (mean age 38 years; 78% female). We estimated the area under the receiver operating characteristic curve and sensitivity, specificity and likelihood ratios for different cut-off points of the IES-R, against a diagnosis of PTSD made using the Structured Clinical Interview for DSM-IV. We performed factor analysis to evaluate construct validity of the IES-R. Results The prevalence of PTSD was 23.9% (95% CI 18.9-29.5). The area under the curve for the IES-R was 0.90. At a cut-off of ≥47, the sensitivity of the IES-R to detect PTSD was 84.1 (95% CI 72.7-92.1) and specificity was 81.1 (95% CI 75.0-86.3). Positive and negative likelihood ratios were 4.45 and 0.20, respectively. Factor analysis revealed a two-factor solution, with both factors showing good internal consistency (Cronbach's factor-1 α = 0.95, factor-2 α = 0.76). In a post hoc analysis, we found the brief six-item IES-6 also performed well, with an area under the curve of 0.87 and optimal cut-off of 15. Conclusions The IES-R and IES-6 had good psychometric properties and performed well for indicating possible PTSD, but at higher cut-off points than those recommended in the Global North.",

keywords = "Global mental health, low-and middle-income countries, post-Traumatic stress disorder, psychological testing, rating scales",

author = "Abas, {Melanie A.} and Monika M{\"u}ller and Gibson, {Lorna J.} and Sarah Derveeuw and Nirosha Dissanayake and Patrick Smith and Ruth Verhey and Andrea Danese and Dixon Chibanda",

note = "Publisher Copyright: Copyright {\textcopyright} The Author(s), 2023. Published by Cambridge University Press on behalf of the Royal College of Psychiatrists.",

year = "2023",

month = mar,

day = "16",

doi = "10.1192/bjo.2022.621",

language = "English",

volume = "9",

journal = "BJPsych Open",

issn = "2056-4724",

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TY - JOUR

T1 - Prevalence of post-Traumatic stress disorder and validity of the Impact of Events Scale-Revised in primary care in Zimbabwe, a non-war-Affected African country

AU - Abas, Melanie A.

AU - Müller, Monika

AU - Gibson, Lorna J.

AU - Derveeuw, Sarah

AU - Dissanayake, Nirosha

AU - Smith, Patrick

AU - Verhey, Ruth

AU - Danese, Andrea

AU - Chibanda, Dixon

PY - 2023/3/16

Y1 - 2023/3/16

N2 - Background A critical step in research on the epidemiology of post-Traumatic stress disorder (PTSD) in low-resource settings is the validation of brief self-reported psychometric tools available in the public domain, such as the Impact Event Scale-Revised (IES-R). Aims We aimed to investigate the validity of the IES-R in a primary healthcare setting in Harare, Zimbabwe. Method We analysed data from a survey of 264 consecutively sampled adults (mean age 38 years; 78% female). We estimated the area under the receiver operating characteristic curve and sensitivity, specificity and likelihood ratios for different cut-off points of the IES-R, against a diagnosis of PTSD made using the Structured Clinical Interview for DSM-IV. We performed factor analysis to evaluate construct validity of the IES-R. Results The prevalence of PTSD was 23.9% (95% CI 18.9-29.5). The area under the curve for the IES-R was 0.90. At a cut-off of ≥47, the sensitivity of the IES-R to detect PTSD was 84.1 (95% CI 72.7-92.1) and specificity was 81.1 (95% CI 75.0-86.3). Positive and negative likelihood ratios were 4.45 and 0.20, respectively. Factor analysis revealed a two-factor solution, with both factors showing good internal consistency (Cronbach's factor-1 α = 0.95, factor-2 α = 0.76). In a post hoc analysis, we found the brief six-item IES-6 also performed well, with an area under the curve of 0.87 and optimal cut-off of 15. Conclusions The IES-R and IES-6 had good psychometric properties and performed well for indicating possible PTSD, but at higher cut-off points than those recommended in the Global North.

AB - Background A critical step in research on the epidemiology of post-Traumatic stress disorder (PTSD) in low-resource settings is the validation of brief self-reported psychometric tools available in the public domain, such as the Impact Event Scale-Revised (IES-R). Aims We aimed to investigate the validity of the IES-R in a primary healthcare setting in Harare, Zimbabwe. Method We analysed data from a survey of 264 consecutively sampled adults (mean age 38 years; 78% female). We estimated the area under the receiver operating characteristic curve and sensitivity, specificity and likelihood ratios for different cut-off points of the IES-R, against a diagnosis of PTSD made using the Structured Clinical Interview for DSM-IV. We performed factor analysis to evaluate construct validity of the IES-R. Results The prevalence of PTSD was 23.9% (95% CI 18.9-29.5). The area under the curve for the IES-R was 0.90. At a cut-off of ≥47, the sensitivity of the IES-R to detect PTSD was 84.1 (95% CI 72.7-92.1) and specificity was 81.1 (95% CI 75.0-86.3). Positive and negative likelihood ratios were 4.45 and 0.20, respectively. Factor analysis revealed a two-factor solution, with both factors showing good internal consistency (Cronbach's factor-1 α = 0.95, factor-2 α = 0.76). In a post hoc analysis, we found the brief six-item IES-6 also performed well, with an area under the curve of 0.87 and optimal cut-off of 15. Conclusions The IES-R and IES-6 had good psychometric properties and performed well for indicating possible PTSD, but at higher cut-off points than those recommended in the Global North.

KW - Global mental health

KW - low-and middle-income countries

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KW - psychological testing

KW - rating scales

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DO - 10.1192/bjo.2022.621

M3 - Article

AN - SCOPUS:85148511208

SN - 2056-4724

VL - 9

JO - BJPsych Open

JF - BJPsych Open

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M1 - e37

ER -

Prevalence of post-Traumatic stress disorder and validity of the Impact of Events Scale-Revised in primary care in Zimbabwe, a non-war-Affected African country

Abstract

Keywords

UN SDGs

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