With the advancements of new technologies, new opportunities to explore genetics in depth have also increased. These innovations have, in turn, developed our understanding of many health conditions, including psychiatric disorders such as obsessive-compulsive disorder (OCD). Genetic link studies in particular are now explored for their ability to shed new light on the potential causes of OCD. The possibilities contained within such research have offered the prospect of a genetic explanation for OCD.
Read on to explore whether OCD may indeed be genetically transmitted. Then, look further into the possibility of OCD as a genetic mutation. Lastly, learn how genetics may impact OCD treatment.
Though the genetic risk for developing OCD is not a simple one, an increased risk of the disorder does appear to run in families. This means parents and siblings share enough genetic elements that they may also have a similar vulnerability to this condition. That said, due to the biological complexities of OCD, being a first-degree relative is only one of several risk factors.
Researchers have recently identified four genes associated with OCD: NRXN, HTR2A, CTTNBP2, and REEP3. Each of these genes impact several neurological pathways related to OCD dysfunction, including synapse connectivity, neurotransmitter release, and the brain circuit linked with habit formation (CRTC). Understanding how genetics influence these processes to become abnormal may offer new insight into the biological basis of OCD and symptom reduction.
Recent findings indicated that both rare and common genetic variants might contribute to the development of many psychiatric disorders, including some related to neurotransmitter systems. OCD’s genetic components have been examined with some unexpected findings, though it is uncertain how clinically useful they are at this stage. Here are some of the most significant results.
Several psychiatric conditions share related genes and variants, creating an overlap of genetic risk, as well. Some OCD symptoms appear in other conditions, such as rumination, which is also a possible symptom in both depression and anxiety disorders. Evidence shows that the genetic foundation of OCD also intersects with autism spectrum disorders and ADHD.
Additionally, ten genes have been identified as being common to the etiology of autism, bipolar disorder, schizophrenia, and OCD. While these four disorders look outwardly distinct, research has found them to, at least in part, stem from a common base of neural pathology.
Genetic research has revealed that OCD has polygenic architecture, which is the contribution of multiple variants or mutations toward the expression of a specific trait. In other words, OCD is not caused by a mutation or change in a single gene but is likely the result of many variant effects. This means that OCD is a complex disorder involving several biological pathways, something that genetic testing for OCD may not be able to clearly discern for some time.
The presentation of the disorder may stem from multiple symptom types, such as ordering, aggression, and hoarding. Some symptoms have associations with other disorders an individual may experience simultaneously with OCD, also known as comorbid disorders. For example, individuals with ordering and symmetry traits may also be more likely to have eating or substance abuse disorders.
Genetic traits do not exist by themselves in a vacuum. Rather, their expression is dependent upon their environmental influences, such as chemical interactions at the molecular level or medical complications during pregnancy. While most have no causal relationship to the development of OCD, recent research has shown that maternal genetic effects contribute significantly to an offspring’s risk.
Pharmacogenetic testing has been developed to explore potential medication responsiveness. This innovation has continued to expand and evolve over the last decade, shedding light on genetic aspects of psychiatric disorders. Some strides have been made for depression and anxiety disorders, but the development of genetic testing for OCD treatment has been minimal.
No single gene has been implicated in an individual’s response to antidepressant treatment for OCD. As studies continue, other biological pathways, such as immune and inflammatory systems, may also emerge as viable treatment targets.
Understanding the neuropathology and potential treatment response to medications may significantly improve outcomes. 40%-50% of patients who take a single type of OCD medication are considered treatment-resistant. Future genetic studies aim to create more targeted treatments, increasing the odds of achieving symptom relief.
Understanding the genetics behind OCD may help clinicians better diagnose and treat the disorder, particularly in pediatric cases when symptoms emerge earlier. With the complexities of genetics and environmental factors, much is still to be learned about OCD. Genetic links may provide a pathway to understanding more about causation and treatment.
