Risk Factors for Adverse Outcomes in Natural and Human-Caused Disasters: A
Review of the Empirical Literature
A National Center for PTSD Fact Sheet
Prepared by: Fran H. Norris, Georgia State University, with the assistance
of: Christopher M. Byrne and Eolia Diaz, Georgia State University, and
Krzysztof Kaniasty, Indiana University of Pennsylvania
The focus of this report is on within-sample factors that influence who is most likely to experience serious and lasting psychological distress as a result of a disaster. As suggested by Freedy et al.1, we differentiated among predisaster, within-disaster, and postdisaster factors.
Predisaster Factors
Gender influenced postdisaster outcomes
in 45 studies, as follows:
- In 42 of 45 studies (93%), women or girls were
affected more adversely by disasters than were men or boys. Panel studies
indicate that psychological effects were not only stronger among females,
but more lasting as well.
- The effects occurred across a broad range of
outcomes, but the strongest effects were for PTSD, for which women's rates
often exceeded men's by a ratio of 2:1.
- The effects of gender were greatest within samples
from traditional cultures and in the context of severe exposure.
Age and Experience influenced
disaster victims' outcomes in 17 samples, as follows:
- A consistent pattern was not apparent within the
findings from the 3 child and adolescent samples.
- Older adults were at greater risk than other adults
in only 2 of the 14 adult samples (14%). Rather than viewing older adults
as an at-risk group, they could be viewed as a resource for disaster
stricken communities.
- Middle-aged adults were most adversely affected in
every American sample where they were differentiated from older and
younger adults. Some research suggests that middle-aged adults are most at
risk because they have greater stress and burdens before the disaster
strikes and they assume even greater obligations afterwards.
- Cross-cultural research suggests that the effects of
age may differ across countries according to the social, political,
economic, and historical context of the disaster setting.
- At least in disasters of smaller magnitude, prior
experience with the specific type of event may reduce anxiety. People who
have experienced previous disasters show higher levels of hazard
preparedness and are more likely to evacuate when authorities suggest they
do.
- Professionalism and training increase the resilience
of recovery workers, although past trauma per se does not.
Culture and Ethnicity shaped the
outcomes of disaster victims in 14 studies, as follows:
- Similar methods for cross-cultural studies of similar
events across 5 studies showed that the effects of the disaster were
greater in developing countries than in the United States.
- Among youths, results for ethnicity were not
consistent. In 2 of the 4 samples (50%), majority groups fared better, and
in 2 (50%), minority groups fared better.
- Among adults, results for ethnicity were quite consistent.
In 100% of the 5 samples, majority groups fared better than ethnic
minority groups.
- There is little explanatory research available, but
the disproportionate risk of psychological distress for adult ethnic minorities
appears to be from both (1) differential exposure to more severe aspects
of a disaster and (2) culturally specific attitudes and beliefs that may
prevent individuals from seeking help.
Socioeconomic Status (SES), as
manifest in education, income, literacy, or occupational prestige, was found to
affect outcomes significantly in 11 samples of disaster victims. In 10 (91%) of
these, lower SES was consistently associated with greater postdisaster
distress. The effect of SES has been found to grow stronger as the severity of
exposure increases.
Family Factors influenced
outcomes in 19 samples, as follows:
- Married status was a risk factor for women. Husbands'
symptom severity predicted wives' symptom severity more strongly than
wives' symptom severity predicted husbands'. Marital stress has been found
to increase after disasters.
- Being a parent also added to the stress of disaster
recovery and, especially for events involving uncertain threats, mothers
were especially at risk for substantial distress.
- Children were highly sensitive to postdisaster
distress and conflict in the family. When measured, parental
psychopathology was typically the best predictor of child psychopathology;
parents who were healthier, less irritable, and more supportive had healthier
children.
- The effectiveness of interventions for children may
be limited if the family is not considered as a whole. In fact, providing
care and support to a child's overly stressed parents might be one of the
most effective ways to care for and support a child affected by disaster.
Predisaster Functioning and
Personality influenced outcomes in 22 samples, as follows:
- Regardless of the data collection method, predisaster
symptoms were almost always among the best predictors (if not the best
predictor) of postdisaster symptoms.
- Many of these studies used lifetime diagnostic
measures to assess a wide range of conditions before and after the
disaster. Persons with predisaster psychiatric histories were
disproportionately likely to develop disaster-specific PTSD and to be
diagnosed with some type of postdisaster disorder.
- In prospective studies using continuous measures of
current symptoms, predisaster symptoms have been found to interact with
severity of exposure. Participants with higher preflood symptoms were more
strongly affected by a flood than were participants with lower preflood
symptoms.
- Having a "neurotic" personality, as opposed
to a stable and calm personality, increases the likelihood that an
individual will experience postdisaster distress. "Hardiness"
decreases the likelihood of postdisaster distress.
Within-disaster Factors
The severity of exposure at the individual or household level
was an important predictor of outcomes in almost all samples.
The presence of all of the following during a disaster has been found, at
least in some studies, to predict adverse outcomes among survivors:
- Bereavement
during the disaster
- Injury
to oneself or a family member
- Life
threat
- Panic
or similar emotions during the disaster
- Horror
- Separation
from family (especially among young people)
- Extensive
loss of property
- Relocation
or displacement
As the number of these stressors increased, the
likelihood of psychological impairment increased. In general, injury and life threat were most predictive of
long-term adverse consequences, especially PTSD.
Neighborhood- or community-level
exposure has been assessed only occasionally, but it appears to have modest
outcomes, as follows:
Personal loss was more strongly related to increases in
negative affect, but community destruction was more strongly related to
decreases in positive affect. This
reflects a community-wide tendency for people to feel less positive about their
surroundings, less enthusiastic, less energetic, and less able to enjoy life
after being exposed to trauma. Such
findings are an excellent reminder that disasters impact whole communities, not
just selected individuals. Although no one would suggest that these community
"symptoms" constitute psychopathology or require professional
intervention, disasters may impair the quality of life in a community for quite
some time.
Postdisaster Factors
- Both life-event stress (discrete changes) and chronic
stress were strong predictors of survivors' health. Moreover, stability
versus change in psychological symptoms was largely explained by stability
versus change in stress and resources.
- Some research suggests that acute stressors (the
individual-level aspects of exposure outlined above) amplify psychological
distress by intensifying or otherwise negatively affecting chronic stressors
such as marital stress, financial stress, and ecological stress.
- Attention needs to be paid to stress levels in
stricken communities long after the disaster has passed.
- Because resources are such an important feature of
the postdisaster environment, they are addressed in detail in Psychosocial Resources in the
Aftermath of Disaster.
Summary and Conclusions
Over the past 20 years, a substantial amount of research has been published
pertaining to risk factors for adverse outcomes. The research base is larger
and more consistent for adults than it is for youths. Even for adults, more
research on many of these topics would be useful and might alter the
conclusions reached thus far. At present, review of the literature yields the
following conclusions:
- An adult's risk for psychological distress will increase as the number of
the following factors increases:
o Female gender
o 40 to 60 years old
o Little previous experience or training relevant to coping with disaster
o Ethnic minority
o Low socioeconomic status
o Children present in the home
o For women, the presence of a spouse, especially if he is significantly
distressed
o Psychiatric history
o Severe exposure to the disaster, especially injury, life threat, and
extreme loss
o Living in a highly disrupted or traumatized community
o Secondary stress and resource loss
- With a few modifications, primarily the deletion of age specifications and
minority group status, this risk-factor model holds reasonably well for children
and adolescents.
- Families are extremely important systems and it is most important that postdisaster
treatment and intervention efforts be aimed at the family unit.
- Outreach efforts for intensive services should focus on areas of the community
where at-risk individuals and families are most likely to live. Treatments
and interventions known to be effective for them should be implemented. It
is important to pay attention to issues of diversity. Less intensive services,
such as support groups and psycho-educational programs, may be adequate for
groups at lower risk.
- It is important to provide support to the supporters in families, especially
wives and mothers.
- Communities might want to encourage groups at very low risk, such as older
adults and childless men, to assume a greater share of the burden for the
community's recovery by volunteering and participating in paraprofessional
activities.
Related Fact Sheets
Epidemiology
Information about rates of PTSD in the United States among different populations
Effects
of disaster
A summary of common traumatic stress reactions including PTSD and Acute Stress
Disorder (ASD)
Magnitude of
PTSD
Empirical review of the literature examining the magnitude, range, and duration
of the effects of disasters over the past 20 years
References
1. Freedy, J. R., Resnick, H. S., & Kilpatrick, D.G. (1992). Conceptual framework for evaluating disaster impact: Implications for clinical intervention. In L.S. Austin (Ed.), Responding to disaster: A guide for mental
health professionals (pp. 3-23). Washington, DC: American Psychiatric
Press.
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