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Fears and phobias: reliability and heritability.
K S Kendler1, L M Karkowski, C A Prescott
1Virginia Institute for Psychiatric and Behavioral Genetics and the Department of Psychiatry, Medical College of Virginia of Virginia Commonwealth University, Richmond 23298-0126, USA.
Psychological Medicine
|July 15, 1999
Summary
Genetic factors significantly influence phobia development, with heritability estimates corrected for unreliability. Individual environmental experiences play a key role in phobia etiology, not familial factors.
Area of Science:
- Psychiatry
- Behavioral Genetics
- Epidemiology
Background:
- Familial factors, including genetic influences, contribute to phobia risk.
- Previous family and twin studies relied on single, potentially unreliable, lifetime assessments.
Purpose of the Study:
- To assess the reliability of lifetime phobia assessments over time.
- To estimate the heritability of various phobias, accounting for measurement error.
Main Methods:
- Two lifetime assessments of five phobias were conducted on 1708 female twins eight years apart.
- Test-retest reliability was assessed in 192 twins one month apart.
- A measurement model was used to estimate genetic and environmental risk factors, correcting for unreliability.
Main Results:
- Short-term phobia reliability (kappa=0.46) was higher than long-term stability (kappa=0.30).
- Heritability estimates, corrected for unreliability, ranged from 43% (any phobia) to 67% (agoraphobia).
- Phobia liability is primarily due to genetic factors and individual-specific environmental experiences.
Conclusions:
- Lifetime phobia assessments exhibit substantial unreliability.
- Corrected heritability for phobia liability is moderate.
- Individual environmental factors are significant in phobia development, while familial environmental factors are not.