Obsessive-compulsive disorder (OCD) can sometimes occur as a relatively distinct problem, with someone's anxiety largely centred around particular intrusive thoughts, fears and compulsions. However, I've also noticed in my clinical practice that OCD sometimes occurs in the context of a much broader difficulty with anxiety and uncertainty. Someone might experience OCD alongside generalised anxiety disorder (GAD), and understanding how these two conditions interact can be an important part of treatment.
What is generalised anxiety disorder?
Generalised anxiety disorder involves excessive and difficult-to-control worry about a range of everyday situations. Someone with GAD might find themselves frequently anticipating negative outcomes, even when there’s relatively little evidence that something bad is going to happen. A particularly important feature of GAD is intolerance of uncertainty. When we're uncomfortable with uncertainty, situations others might regard as relatively ordinary can feel threatening or difficult to manage. We might find ourselves thinking, "What if something goes wrong?" or "How can I make absolutely sure everything will be okay?" As a result, we may develop ways of trying to manage uncertainty and create a greater sense of control. This might involve avoiding unpredictable situations altogether, or relying heavily on planning, preparation, routines and structure.
Of course, planning and organisation aren't inherently problematic. But when they become excessive attempts to eliminate uncertainty, they can actually reinforce our anxiety. And because life is inherently uncertain, the search for complete control can become exhausting.
GAD is also very common. The 2023/24 Adult Psychiatric Morbidity Survey found that approximately 7.5% of adults in England met criteria for GAD during the week assessed.
How does GAD overlap with OCD?
Although GAD and OCD are distinct conditions, they have an important feature in common: difficulty tolerating uncertainty. In OCD, an intrusive thought or feeling can create a powerful sense of doubt. Someone might worry that they've harmed another person, contaminated something, made a terrible mistake or overlooked an important risk. Compulsions are then performed to reduce this uncertainty, prevent a feared outcome, or regain a sense of control.
In GAD, worry and attempts to control uncertainty tend to extend across a broader range of everyday concerns. The underlying processes can therefore look remarkably similar. In fact, research suggests that GAD and OCD frequently coexist. A systematic review found that approximately 17% of people with OCD also experienced GAD, although the figures varied considerably between studies.
Can generalised anxiety make OCD worse?
I think this is where the relationship becomes particularly interesting. If someone already experiences considerable anxiety about uncertainty, it makes sense that they might be particularly vulnerable to becoming caught up in obsessive-compulsive patterns. After all, compulsions can offer something that feels very appealing when we're anxious: a sense of certainty or control. Checking, seeking reassurance, reviewing memories or mentally analysing a question might temporarily make us feel safer.
The problem, of course, is that this relief is usually short-lived. By repeatedly responding to uncertainty as though it's dangerous, we can reinforce the very fears we're trying to overcome. In this sense, I think compulsions can sometimes become a way of coping with the broader difficulty of tolerating uncertainty. This doesn't mean that GAD necessarily causes OCD, or that everyone experiencing OCD has underlying generalised anxiety. But the two conditions can interact in ways that make the OCD cycle particularly difficult to break.
We might also notice that OCD becomes more troublesome during periods of stress, change or uncertainty, when our usual sense of control feels threatened.
What happens when we treat OCD?
Another interesting observation from my clinical practice is that sometimes, as someone's OCD improves, their underlying generalised anxiety becomes more apparent. This might sound a little strange. Surely overcoming OCD should make someone feel less anxious? Well, often it does. But if compulsions have also been a way of managing broader feelings of uncertainty, reducing them can initially leave someone feeling exposed. It's almost as though we've taken away a coping strategy, even if it was ultimately maintaining the problem. Someone might become much better at resisting OCD compulsions, yet still notice that they're frequently worrying about work, relationships, finances or what the future might hold.
In some cases, the generalised anxiety was there all along, but had been overshadowed by the more obvious OCD symptoms. This isn't a reason to avoid treating OCD. Nor does it mean that treatment has somehow failed. It simply means that there may be another difficulty that deserves attention. And fortunately, GAD is also very treatable, particularly through cognitive behavioural therapy (CBT).
Why do some people struggle with uncertainty?
The causes of GAD are complicated and aren't always clear. Like many mental health conditions, it's likely to develop through a combination of genetic, psychological and environmental factors. However, one thing I sometimes explore with patients is whether earlier life experiences may have influenced their relationship with uncertainty. For example, someone who experienced significant adversity, unpredictability or instability during childhood might have learned that the world is a rather dangerous place. They may have developed beliefs that:
Bad things can happen unexpectedly.
Uncertainty is something to fear rather than tolerate.
Being prepared and in control is essential for staying safe.
They're particularly vulnerable when things don't go according to plan.
These beliefs can be understandable responses to difficult experiences. If life has repeatedly taught us that unexpected events lead to distress, it makes sense that we might become especially motivated to anticipate and prevent future difficulties. Over time, this could contribute to patterns of excessive worry, vigilance and attempts to control uncertainty.
Of course, not everyone with GAD has experienced childhood adversity, and difficult early experiences don't inevitably lead to anxiety disorders. But understanding how someone came to view uncertainty as threatening can sometimes provide valuable insight into their difficulties.
Can OCD and GAD be treated together?
Yes, absolutely. Interestingly, there's also considerable overlap in the medications used to treat these conditions. Selective serotonin reuptake inhibitors (SSRIs), a type of antidepressant, are commonly used to treat both OCD and GAD. Although this doesn't necessarily mean the conditions have identical underlying causes, it's another interesting similarity between them. Psychological treatment, however, can differ. CBT for OCD typically focuses on changing how we respond to intrusive thoughts and uncertainty, particularly through exposure and response prevention (ERP), which involves gradually reducing compulsions and avoidance.
CBT for GAD tends to focus more broadly on excessive worry, beliefs about uncertainty, and strategies people use to anticipate or control potential threats. Fortunately, when someone experiences both OCD and GAD, we don't necessarily need to treat them as entirely separate problems. Both difficulties can be understood within a shared psychological formulation, and the treatment approaches can be incorporated into the same course of therapy.
Sometimes it makes sense to prioritise the OCD, particularly when compulsions are significantly interfering with everyday life. Other times, broader patterns of worry and anxiety might need attention alongside the OCD. The important thing is to recognise the different processes maintaining each difficulty and tailor treatment accordingly. Ultimately, the aim is to help someone become more comfortable living with uncertainty, without feeling compelled to constantly anticipate, prevent or control everything that might go wrong. We can't eliminate uncertainty from life, but we can learn to live with it.