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Phobia. www.psychlotron.org.uk. Main symptoms: Marked and persistent fear Anxiety response Avoidance Interferes with everyday activities Duration 6 months or more Affects 6-11% of population (more F) Lifetime problem in 10% of cases. Explanations of Phobia. www.psychlotron.org.uk.
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Phobia www.psychlotron.org.uk • Main symptoms: • Marked and persistent fear • Anxiety response • Avoidance • Interferes with everyday activities • Duration 6 months or more • Affects 6-11% of population (more F) • Lifetime problem in 10% of cases
Explanations of Phobia www.psychlotron.org.uk • Biological • Genetics • Nervous system abnormalities • Psychological • Learning theory
Genetic Influences www.psychlotron.org.uk • Compare concordances of MZ & DZ twins • Greater similarity of MZ twins is assumed to indicate a genetic influence
Genetic Data (Simple Phobia) www.psychlotron.org.uk
Genetic Data (Simple Phobia) www.psychlotron.org.uk • MZ concordance usually significantly higher than DZ • Suggests genetic influence • MZ concordance always significantly lower than 100 • Indicates environmental influence is also in operation
Twin Studies www.psychlotron.org.uk • Commonly affected by several problems: • Small samples (NB: not always – check) • Unreliable zygosity tests (early studies only) • MZ twins tend to be treated more similarly than DZ, which may account for greater similarity • DZ twins can be M&F, which may be important with sex-differentiated disorders (like simple phobia)