Post-traumatic stress after terrorist attack: psychological reactions following the US embassy bombing in Nairobi. Naturalistic study
Njenga FG, Nicholls PJ, Nyamai C, Kigamwa P and Davidson JRT;
Commented by , 25 Oct 2004
Aims of the study
- To assess the prevalence of post-traumatic stress disorder (PTSD) after terrorist attacks
- To identify risk factors for developing PTSD after terrorist attacks
Method
2627 subjects out of an initial sample of 2883 participated in the study. Participants were part of a non-random sample of Kenyans, who had witnessed the bombing that occurred on August 7, 1998, outside the US embassy in Nairobi, Kenya. The blast killed over 200 people and approximately 5000 others were hospitalised for their injuries.
Information on psychological reactions following the attack was gathered using a self-report questionnaire, consisting in 57-items, assessing demographic factors, level of exposure to the bombing, injuries incurred during the attack, PTSD symptoms required for a diagnosis of PTSD according to DSM-IV, and economic difficulties and concerns. Anwers to the questionnaire were given by the participants 20 days to more than 3 months after the attack.
Results
- 929 (35.4%) participants met criteria for PTSD.
- Factors associated with the development of PTSD included:
- demographic variables: female gender, unmarried, no college education
- exposure and injury factors: location outside of a building, seeing the blast, getting injured, not recovering from injury
- peritraumatic reactions and sequellae: feeling afraid, helpless or threatened, not confiding to a friend, bereavement
- financial sequellae: financial difficulties after the attack, inability to work owing to injury
Professor Pull's comments
The study has a number of obvious flaws and limitations. First of all, it is based on a sample of convenience, i.e. not a random sample as would be expected in an epidemiological study. Second, the instrument used in the study was an ad hoc instrument, that had not been tested with regard to any one of its psychometric characteristics, such as its reliability, sensitivity, or validity. Finally, the timeframe for the assessments was quite variable, from 20 days to 99 days after the attack.
In spite of these limitations, this is an important study. First, it is based on an African sample, while most other studies in this field have been completed in Western countries. Second, the size of this sample is quite large. Third, the links that have been found in the study between a number of risk factors and the subsequent development of PTSD are strong links.
The results confirm findings of previous studies that have been done with a more stringent methodology. In a recent review on PTSD after terrorist attacks, Gidron (ref. 1) describes 6 studies involving a deliberate human-made violent event with a political motive. Based on those studies, the author estimates the prevalence of PTSD after terrorist attacks worldwide to be 28%.
In addition, several of the risk factors identified by Njenga et al have also emerged from some of these studies, in particular injury during the attack and proximity to the event. There are, however, many inconsistencies with regard to risk factors after terrorist attacks and further investigations are needed in this field.
Reference
1. Gidron Y (2002). Post-traumatic stress disorder after terrorist attacks: a review. Journal of Nervous and Mental Disease, 190, 11-121.