Epidemiology
Prevalence
According to the DSM-5, in the United States, it was found that the 12-month prevalence of OCD is 1.2% which is not very different from the international prevalence that is in between 1.1% and 1.8% (APA, 2013). In addition, more than 90% of the OCD cases were found to be have both obsessions and compulsions together (Butcher et al., 2013). The onset of OCD usually occurs about late adolescence and early adulthood (Butcher et al., 2013). Moreover, while females are seemed to be more affected form OCD in adulthood, conversely, males are more commonly affected from the disorder in their childhood (APA, 2013).
Comorbidity
According to the DSM-5 statistics, 76% of the cases with OCD have also other anxiety disorders such as panic disorder, social anxiety disorder, specific phobia and generalized anxiety disorder (APA, 2013). On the other hand, the comorbidity between affective disorders and OCD seems also high, which is 63% for any depressive or bipolar disorder and 41% for only depressive disorders (APA, 2013). There is an essential point to mention about depressive disorders and anxiety disorders with OCD that is while mostly OCD follows anxiety disorders, depressive disorders may occur after OCD (APA, 2013). Furthermore, it was found that while 23% and 32% of the OCD cases can have obsessive-compulsive personality disorder, 30% of them have tic disorder in lifetime period which is most common in males with the onset in childhood (APA, 2013; Thomsen, 2013). In children there is a frequently seen triad which is the occurance of tic disorder, ADHD and OCD together (APA, 2013). Additionally, there is also comorbidity between OCD and other related disorders like body dysmorphic disorder, hair-pulling disorder, skin-picking disorder and the oppositional defiant disorder because of the component of impulsivity in this disorder (APA, 2013). Lastly, it was found that the 12% of OCD cases can also be diagnosed with schizophrenia and schizoaffective disorder (APA, 2013).
Identification of possible causes and risk factors of OCD also has a crucial role to understand more about the prognosis, prevention and treatment of the disorder. In the next section of this paper, the risk factors are examined in a biopsychosocial cultural perspectives with some cognitive vulnerabilities specific to OCD.
Etiology
Biological Factors
Genetics
In most of the studies which were conducted with twins and families results demonstrate the great importance of the genetic factors on OCD. In twin studies, it was found that in identical twins, OCD is seen more frequently than the fraternal twins; and in family studies, among first degree relatives, OCD is seen 3 or 12 times more than normal prevalence (Butcher et al., 2013). In addition, findings show that in early onset of OCD genetics has more effect on the occurrence of the disorder than in later onset of OCD (Butcher et al., 2013).
Brain Functions
The studies which investigated the role of brain functions in OCD led to the similar results. It was demonstrated with brain imaging methods that the individuals with OCD generally have some abnormalities in subcortical structures such as basal ganglia which is a part of the limbic system, and excessive activation in orbitofrontal cortex and singulate frontal cortex which is again a part of the limbic system (Butcher et al., 2013). As a matter of fact, these structures of brain are mostly responsible from some primitive behaviors such as sexuality, aggression and cleaning (Butcher et al., 2013).
Neurotransmitter Abnormalities
The abnormalities in the serotonergic system is identified to be related to OCD which refers mostly to the increased level of serotonin or the because of some brain structures that are highly sensitive to serotonin (Butcher et al., 2013). Besides serotonergic system, recently the other systems have been also found to be have a role on OCD such as dysregulation of glutamate and dopaminergic system (Pittenger, Bloch, & Williams, 2011; Butcher et al., 2013).
Psychosocial Factors
Early life experiences, attachment and parenting style, stressful life events, familial and personality factors seem to have a precipitating impact on the onset of OCD according to the recent studies:
In a study conducted by Benedetti and his colleagues (2014), it is found that adults who experienced negative experiences in their childhood such as being exposed to both physical and emotional abuse and also neglect, are associated with treatment seeking behavior or early application to the consultant, especially in females, which is also suggests a gender difference.
In another study conducted by Doron and his colleagues (2012), it is found that insecure attachment in adulthood is found higher among people with OCD, even depression is controlled. Insecure attachment style in childhood is also seemed to have a connection to the OCD as it is proved in a study conducted by Rezvan and her colleagues (2012) which indicates the insecure attachment style in childhood and poor communication between parents and children contributes to the childhood onset of the OCD. Related with parenting, another study conducted by Timpano and her colleagues (2010) supports the protective factor of positive and warm relationships between parents and child by suggesting that authoritarian parenting style is significantly related with OCD symptoms in the adulthood. In addition, Clark and Beck (2010) in their book, drew attention to the other stressful life events specifying the important changes in a life course such as pregnancy, childbirth or traumatic events as possible triggers on the onset of the OCD, however they also mentioned that many cases also do not report any particular triggering event.
Another study conducted by Mataix-Cols and his colleagues (2013) offers the importance of environmental factors like family environment on OCD with suggesting that there is a high risk of OCD also for relatives with no biological connections such as spouses. Besides a study conducted by Murphy and Flessner supports the point about the impact of family environment on OCD suggesting a powerful relationship between childhood onset OCD and negative family functioning such as depression and anxiety symptoms seen in parents, feelings of guilt in parents and family accommodation.
Looking at the 5-factor personality traits which can be possibly related to OCD symptoms, only conscientiousness is found to reveal the most significant relationship with OCD (Inchausti et al., 2015).
Cognitive Factors
As in the famous example in which “not thinking about the white bear†is requested but individuals generally end up thinking of it more, suppressing the obsessive thoughts also makes them stronger and increases their frequency of occurrence as it is usually the case for the individuals with OCD, since they generally find their obsessions unacceptable and suppress them consequently (Butcher et al., 2013).
Another cognitive related phenomenon in OCD is evaluating one’s responsibility in his or her obsessive thoughts in an exaggerated way as if assuming that even the thought of engaging in an action is morally equals to actually doing it or thought of committing a negative action increases the possibility of committing it actually (Butcher et al., 2013). This phenomenon also called as “thought-action fusion†that triggers compulsive behaviors which are carried on to prevent “harmful†events (Butcher et al., 2013).
Cultural Factors
Looking at the literature, it can be concluded that OCD symptoms show some differences across different cultures. For instance, contamination and dirt obsessions seem to be more frequently seen than the obsessions about sex and religion in the sample comprising of Indians (Clark, 2007). Furthermore, religious obsessions might be more common in cultures that employs strict religious rules (Clark, 2007). According to another study conducted by Yorulmaz and Işık (2011) with Turkish and Western sample, it was found that thought-action fusion in the field of morality is more related with OCD symptoms in Turkish participants than Western participants.
The topics that are covered so far help to understand the main characteristics of OCD in a greater extent. However, undoubtedly, it is crucial to review the methods of assessing the OCD symptoms to reach the valid conclusions on diagnosis and treatment.