Is OCD Genetic?
Many of my clients want to know why they have OCD. Why is it that they got stuck with such a painful collection of thoughts and emotions? Was it something that happened to them when they were younger? Was it something about their family or how they were raised? Or was their OCD caused by their genes?
It’s entirely understandable to want to better understand why we have OCD. One of the most logical reasons we want to understand what caused our OCD is the idea that if we know what caused it then we can better understand how to treat it.
I describe this understandable way of thinking in my 2025 book chapter Precision Psychiatry: Promises, Shortcomings, Dangers. For example, in that chapter, I describe how numerous forms of cancerous lesions are analyzed to determine specific genetic variants. The reason this analysis is done is that awareness of the specific genetic variants can be used to more precisely tailor treatment, resulting in improved outcomes.
So, if genetic analysis can improve cancer treatment, maybe understanding the genetics of OCD can help the OCD treatment process.
Below, we’ll review what we know about the genetics of OCD and what this means for those of us participating in OCD treatment.
What Does “Caused” By Genetics Mean?
When my clients ask me if their OCD is caused by OCD, what they typically mean (even if they didn’t frame the question like this) is if their OCD was inevitable and if their OCD is immutable.
Let’s explore what I mean by inevitable and immutable, starting with inevitable.
Usually, when someone wonders if their genes caused their OCD, they think that their genes are “hardwired” for OCD – that, given the genes they have, their OCD was going to emerge no matter what.
Interestingly, this idea – that OCD was inevitable for some people – is far from the truth. How do we know that this is far from the truth?
Here’s the easiest way to explain how we know OCD isn’t inevitable. Consider two identical twins. Like all identical twins, these two identical twins share, basically, 100% of the same genes.
On average, if one of these identical twins is diagnosed with OCD, only about 50% of the time is the other twin diagnosed with OCD. This is a similar pattern found to other mental disorders like major depressive disorder and schizophrenia. Although specific concordance percentages vary between mental disorders, no mental disorder has a 100% concordance rate in identical twins. What this means is that even though their genotype is close to 100% the same, that genotype alone does not determine the emergence of OCD.
It’s because of data like this (and other research such as genome-wide association studies) that researchers classify OCD, like other mental disorders, as massively multifactorial. Massively multifactorial means that what causes OCD is a vast combination of numerous factors, including an individual's genotype, environment, relationships, cognitive factors, etc. This is why we can confidently say that any given person’s OCD is not inevitable because of “hardwiring” or genes.
This leads to the next question: Is OCD immutable?
Is OCD Immutable?
In this context, immutable means malleable or changeable. For instance, no amount of psychotherapy (as far as we know) is going to change the color of your eyes or how tall you are. So, when a client asks, “Is my OCD caused by my genes” they often mean “Am I going to be stuck with OCD for the rest of my life?”
In contrast to your eye color or your height, OCD is changeable and highly treatable with appropriate care. Importantly, we don’t have to know exactly what causes OCD in order to effectively treat it. Of course, it might be helpful to have more information about what causes OCD and, in the future, this information may change how we treat it. But presently, our front-line interventions for OCD (like exposure and response prevention; ERP) are very dependable treatments.
One way I explain to my clients why we don’t need to know the exact causes of OCD to effectively treat it is like this: Imagine we’re doctors at a hospital. A patient is brought to the emergency room with a stab wound. While it might be useful to know the specific knife that caused the wound, we don’t need to know exactly what knife caused the wound to effectively treat the patient. Whatever kind of knife caused the wound, we’ll attend to the treatment similarly (with disinfectants, stitches, etc). Likewise with OCD. We don’t need to know precisely what caused OCD in order to apply our best, science-backed treatments. And those treatments are very beneficial.
Finally, sometimes my clients are wondering about the role of genetics in treating OCD because they’re exploring the possibility of using medications (like selective serotonin reuptake inhibitors; SSRIs) to treat their OCD. That’s a larger subject, but I describe it in detail here.
So, taken as a whole, here’s what we know. Genes probably play some kind of role in the development of OCD (although the role of genes in mental disorders, like OCD, is debated). However, that genes may play some kind of role in the development of OCD doesn’t mean that OCD is inevitable or immutable. For those experiencing OCD, their likely best path forward is to connect with an OCD specialist to discuss their diagnosis and treatment options.