Date of Award

Summer 2011

Document Type


Degree Name

Doctor of Philosophy (PhD)




Clinical Psychology

First Advisor

Guastello, Stephen J.

Second Advisor

Saunders, Stephen M.

Third Advisor

Wierzbicki, Michael


Comparatively few studies of obsessive compulsive disorder (OCD) have addressed the interpersonal dynamical patterns within families that could exacerbate or quell symptom severity in the ill relatives or hypothesize other roles for familial variables. Furthermore, the extant studies have relied primarily upon linear models. Methodological limitations of linear models, such as assuming that change occurs as the result of unidirectional influences and that the scores obtained for each variable are independent of each other are at variance with temporal, dynamic phenomena and have restricted the empirical investigations of the dynamics of OCD.

The current study investigated whether OCD could be considered a dynamical disease such that the complex rhythmic processes that are the norm for living things would be replaced by relatively constant dynamics or by periodic dynamics. Determining whether OCD could be a dynamical disease could improve our current treatment strategies or lead to the development of new treatment strategies, by finding ways to best control or alter the dynamics of the family system and determining when the best time for change could take place. To accomplish this, this study analyzed both the occurrence of rituals as they transpired over time and the influence the family may have had upon the spatiotemporal structure of symptoms.

This information was obtained by using the time-diary method and comparing the time-series of 17 clinical cases with 16 matched controls. Comparisons of nonlinear regression parameters and Lyapunov exponents revealed that OCD exhibited a low-dimensional deterministic structure. The average nonlinear model (R2 = 0.32) explained more than 10 times the variance of its linear counterpart (R2 = 0.03). Family reactions and emotional responses accounted for only a very modest increase in the variance explained by the nonlinear regression model or in the amount of turbulence.

Family reactions and emotional responses do little to make the rituals go away, but instead may strengthen the dynamics. Finally, significant rank order correlations were found between the R2 for each logbook and Lyapunov exponents with symptom severity and family reactions. Theoretical and practical implications of the results are discussed, including implications for treatment.