Etiological factors that contribute to Obsessive-Compulsive Disorder (OCD). Obsessive-compulsive disorder is characterized by elevated anxiety caused by uncontrollable and intrusive thoughts called obsessions, and repetitive, ritualistic behaviors called compulsions (March & Mulle, 1998). Children and adolescents with obsessive-compulsive disorder (OCD) cannot stop their worrying and anxiety. Obsession themes may include contamination, harming oneself or others, aggression, sexual misconduct, religiosity, forbidden thoughts, symmetry urges, and the need to tell, ask, or confess (March & Mulle).
Compulsions take the form of overt behavioral acts, rituals or covert mental acts (e.g. silently counting). Compulsions may also include washing, repeating, checking, touching, counting, ordering/arranging, hoarding and praying (March & Mulle). Compulsions function to reduce the anxiety associated with the child’s or adolescent’s obsessions (American Psychological Association [APA], 2000). For example, a child with contamination obsessions may experience intrusive thoughts about catching a disease from touching a surface and then compulsively wash his or her hands for extended periods to lessen fears about being contaminated.
There is consistent evidence to suggest that obsessive– compulsive disorder (OCD) encompasses a few consistent and temporally stable symptom dimensions, which may coexist within an individual patient. These major dimensions typically include contamination/washing, harm/checking, symmetry/ordering, hoarding, and forbidden (sexual/religious) thoughts.[1,2] Each has been associated with distinct patterns of genetic and environmental influence[3,4] ; comorbidity with other psychiatric disorders[5,6] ; and treatment responsiveness.[7,8] Neurobiological studies also suggest that these symptom dimensions may, in part, reflect distinct underlying pathophysiological processes.[9–11] For example, elevated amygdala responsiveness to threat—a common finding in other anxiety disorders (ADs)—is most evident in OCD patients with prominent harm/checking and/or forbidden thoughts. Thus, there is accumulating evidence to suggest that dimensionspecific etiological influences contribute to the overall presentation of OCD, although precisely how such influences manifest remains a topic for ongoing research.
The purpose of this chapter is to provide an overview of the current research on the causes and etiology of OCD. To do so, we will examine the state of the field from psychological, biological, and evolutionary perspectives, and attempt to synthesize the literature into a coherent picture of where we as a field are in our understanding of why 1-3% of the population qualifies for a diagnosis of OCD (Abramowitz, Taylor, & McKay, 2009).