CO2-induced panic attacks: a twin study.
OBJECTIVE
The authors investigated the role of genetic factors in 35% CO2-induced panic attacks.


METHODS
Ninety twins recruited from the general population were challenged with one-vital-capacity inhalations of 35% CO2-65% O2. Probandwise concordance rates were calculated and rates compared for monozygotic and for dizygotic twins.


RESULTS
A significantly higher concordance was found for 35% CO2-induced panic attacks among monozygotic than dizygotic twins (55.6% versus 12.5%).


CONCLUSIONS
These results suggest a relevant role of genetic factors in 35% CO2-induced panic attacks.
Bellodi
L
L
Department of Neuropsychiatric Sciences, Istituto Scientifico H.S. Raffaele, Milan, Italy.
Perna
G
G
Caldirola
D
D
Arancio
C
C
Bertani
A
A
Di Bella
D
D
D000328:Adult; D002245:Carbon Dioxide / Q000008:administration & dosage / Q000494:pharmacology; D004200:Diseases in Twins / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008957:Models, Genetic; D016584:Panic Disorder / Q000139:chemically induced* / Q000453:epidemiology / Q000235:genetics*; D015995:Prevalence; D012737:Sex Factors; D014429:Twins, Dizygotic / Q000235:genetics / Q000706:statistics & numerical data; D014430:Twins, Monozygotic / Q000235:genetics / Q000706:statistics & numerical data
D002245:Carbon Dioxide