Backgroundand Aims: The stability over time for avoidant personality disorder (AVPD) and obsessive-compulsive personality disorder (OCPD) has previously been found to be moderate. However, the mechanisms underlying this temporal development are not well understood. In the present study we estimate the influence of genetic and environmental factors on stability and change in AVPD and OCPD. Methods: AVPD and OCPD traits were assessed using the Structured Interview for DSM-IV Personality in 2,793 young adult twins from the Norwegian Institute of Public Health Twin Panel (wave 1). On average 10 years later (wave 2) 2,282 of these were re-interviewed. Longitudinal biometric models were fitted to dimensional representations of AVPD and OCPD. Results: The number of endorsed sub-threshold criteria for both PDs decreased 31% from wave 1 to wave 2. The correlations between the numbers of traits endorsed at the two time points were 0.54 for AVPD and 0.37 for OCPD. Genetic factors contributed 67% and 53%, respectively, to the stability of AVPD and OCPD. The correlations between the genetic factors influencing AVPD and OCPD at the two time points were 1.00 and 0.72 respectively, while the environmental influences correlated 0.26 and 0.23, respectively. The correlation between the stable risk factors for AVPD and OCPD was 0.39 of which 63% was attributable to genetic influences. Conclusion: Both AVPD and OCPD were moderately stable from young to middle adulthood. Stability was in large part due to genetic factors, whereas environmental influences contributed to change.
Vi er endelig tilbake med tredje sesong av Udannet. Knut har vært i Oslo og besøkt Line C. Gjerde som jobber som doktorgradsstipendiat ved Folkehelseinstituttet (FHI). Line holder på med tvillingforskning som blant annet innebærer å finne ut hvor arvelig forskjellige psykologiske egenskaper og fenomener er. Knut og Line snakker en del om metodologien bak tvillingforskning og hvordan det lar seg gjøre å forske på arvelighet og psykiske lidelser, uførepensjon og sykefravær. Vi kommer også inn på overgående tema i psykologifaget og statistisk metode. Og ja, du trodde SPSS brukte tid på kjøre statistiske analyser?