Understanding PTSD Flashbacks vs. OCD Intrusive Thoughts

Your mind is a treasure trove. It holds your memories, your future desires, and an impressive amount of info on that one random topic that you seem to know everything about. 

But it can also betray you, particularly in the case of intrusive thoughts and flashbacks. Suddenly, a thought may pop into your head that makes you confused: What if you just rammed your car into the SUV in front of you at the stop light? Or, a specific smell takes you back to your childhood home where you experienced abuse.

Both of these things can cause incredible distress. And you may go to great lengths to dodge them—abusing substances so you can sleep off the afternoon to avoid a flashback or repeatedly washing your hands until they bleed, are just two examples.

In this article, we’ll explore the differences between intrusive thoughts and flashbacks, how they relate to obsessive compulsive disorder (OCD) and posttraumatic stress disorder (PTSD), and why the two disorders occur together more commonly than you might think.  

What are Intrusive Thoughts?

You’re just sitting there minding your own business when a disturbing thought pops into your head. It feels so real—maybe even shameful or confusing. Whatever the content, the intrusive thought may send a wave of anxiety your way. 

“Everyone has intrusive thoughts,” says Patrick McGrath, PhD, Chief Clinical Officer at NOCD. Intrusive thoughts can be about anything, including things that happened (like something embarrassing in your past) and things that didn’t (a specific anxiety or fear that pops into your head). Intrusive thoughts are often of the “what if” variety, involving distressing topics, and they tend to occur more than once, often unpredictably. 

Because intrusive thoughts can involve sexual or violent themes (or other taboo things that cause you shame), it’s tempting to try to avoid thinking about them. However, it’s important to remember that an intrusive thought does not mean that you want to do the things that are in your thoughts. But even with this knowledge, they can take on a life of their own, causing you to fixate on them, feeling that you absolutely need to resolve them or get rid of them. That’s when they become obsessions.

As a result, you may begin to engage in repetitive behaviors, called compulsions. Performing compulsions—arranging things just so, opening and closing your car door a certain number of times, sanitizing something thoroughly, asking a friend if they think you could ever act on a scary thought—exist in response to these intrusive thoughts with the goal to feel better or to prevent something “bad” from happening. Doing them brings relief for a certain period of time. Then, an intrusive thought emerges again, and you feel forced to perform the behaviors. And the cycle continues: “It’s like you’re on a hamster wheel, and just running from obsessions all the time,” Dr. McGrath says.

The vicious cycle of intrusive thoughts and compulsive behaviors is the driving force behind OCD. And the more you engage in these compulsive behaviors, the stronger OCD—and thus intrusive thoughts—become, says Dr. McGrath. “OCD is nicknamed ‘the doubting disorder.’ Your OCD will tell you that if you just give it the right answer, everything will be great. The problem is, OCD will doubt every answer you give it. You can never satisfy it,” he says.  

What are Flashbacks?

You were in a car accident. You walked away okay, but every time you hear the screech of tires, your heart races, you break out into a cold sweat, your back begins to hurt, and you can hear the wail of sirens coming down the street. 

“Flashbacks can be a subset of intrusive thoughts, and they typically revolve around memories about trauma,” Dr. McGrath says. “During a flashback, you relive the experience of a traumatic event,” he explains. In short, you can consider them a playback of a horribly painful memory.

Flashbacks are often triggered by something sensory in your environment, such as a specific smell or like sound that reminds you of the trauma. During a flashback, you’re zipped straight back to that experience. For example, war veterans may hear a car backfiring or fireworks going off and immediately be taken back to their time in service. “So many veterans hate the 4^th of July. They feel as if they’re being shot at all over again all night long,” Dr. McGrath describes. In response, it’s not unusual for people to try to isolate themselves in an effort to avoid anything that could remind them of the trauma. People can also experience flashbacks as nightmares, he says; in response, they may even try to avoid sleeping. 

Flashbacks can be brutal, and people will do whatever they can to find safety as quickly as possible. Therefore, having one can send your brain into “fight, flight, or freeze” mode. This might include running away from a perceived threat, for instance. As you’re reminded of the memory and have to relive it again, you may feel as if you won’t be able to make it through, and do anything to avoid it. 

What is PTSD?

PTSD stands for posttraumatic stress disorder, which can occur if you’ve experienced or witnessed something traumatic, such as natural disasters, accidents, war, sexual assault, abuse, and bullying, according to the American Psychiatric Association. Common feelings that go along with PTSD include sadness, fear, anger, and detachment. 

About 3.6% of adults in the U.S. had PTSD in the past year, according to the National Institute of Mental Health (NIMH). But nearly twice that many people (6.8%) experience PTSD at some point in their lifetime. Nearly three times the number of females have PTSD compared to males.

The long-term effects of PTSD can ripple through an entire family. As the U.S. Department of Veterans Affairs points out, PTSD can affect your ability to form close relationships with friends, family, partners, and your children. Research shows that suicide rates are up to seven times higher in the PTSD population compared to those without PTSD, according to research on more than three million Swedish adults in the Journal of Affective Disorders in 2021.

Can PTSD Trigger OCD?

Yes—OCD and PTSD commonly occur together. Among the roughly 30% of people with PTSD who also experience OCD, most experienced a traumatic event before they developed OCD. 

Intrusive thoughts can occur in OCD and PTSD, triggering you to engage in compulsions in order to feel safer. For instance, if you experienced violence, you may now obsessively check your doors or use repetitive behaviors in order to avoid intrusive thoughts about your trauma. 

PTSD and OCD occur together more commonly than you might think, says Dr. McGrath. “OCD is an opportunistic jerk of a disorder. OCD will notice if you’ve been through something difficult and come in and tell you that it can prevent the intrusive thoughts—as long as you do these compulsions, bad things won’t happen,” he describes. Of course, none of that is true.

In research on 51 adult civilian survivors of the Kosovo War, 35% and 39% were likely to have obsessive-compulsive disorder and posttraumatic stress disorder, respectively, according to a 2016 study in BMC Psychiatry. Those who had more severe PTSD were also more likely to also have OCD, the researchers found. In addition, another study in 2019 in the Journal of Cognitive Psychotherapy found that of 318 veterans with PTSD, 36% also had obsessive compulsive tendencies.

After trauma, if you’ve noticed that you’ve also developed repetitive behaviors, you may have OCD. It’s important to know that you are not “stuck” with these thoughts and behaviors, and there is help available. You can work with a qualified mental health professional to develop the proper treatment plan for you.

How to Get Help for PTSD-Related Flashbacks and Intrusive Thoughts

If you’re suffering from flashbacks and distressing intrusive thoughts, you should work with a clinician who has been trained in treating both PTSD and OCD, taking into account how they occur together. “This can be a difficult treatment decision. Let’s say I have to treat this patient for OCD, but exposure therapy might trigger flashbacks. What we’ve done at NOCD is train therapists to start with PTSD work to address trauma and manage flashbacks and nightmares. After that, we move to treating the OCD with ERP (exposure and response prevention) work, which helps them decrease their compulsions,” Dr. McGrath explains. 

In short, this combined approach will employ: 

• Prolonged exposure (PE) therapy to treat PTSD. During this form of exposure therapy, your clinician will help you gradually expose yourself to your fear, which will help you process and move through it.  
• Exposure and response prevention (ERP) to treat OCD, which we’ll get into below. 

Unfortunately, people who go through traditional crisis counseling or therapy may find that their PTSD symptoms only get worse. That’s because that type of treatment does not put you face-to-face with your fears so you can learn to overcome them. “If you think about it, PTSD is the fear of a memory,” says Dr. McGrath. “You want people to face the things that are in their memories so they can become unstuck,” he says. 

The addition of PTSD therapy takes longer compared to ERP therapy for OCD only, which may take about 12 initial sessions. When PTSD and OCD are treated concurrently, you might expect results in 22 to 25 sessions, he says. After that, you may go into the maintenance phase of treatment, which may look different for everybody. 

When Your Intrusive Thoughts are Related to OCD: How to Get Help

Exposure and response prevention (ERP) is the optimal treatment for OCD. In ERP, you carefully, gradually confront the persistent thoughts, urges, and impulses (obsessions) that trigger you to use repetitive behaviors (compulsions) in an attempt to neutralize them or make them go away. Instead of doing compulsions, you learn to handle whatever it is that pops into your head. 

Together with your therapist, you will come face to face with objects, situations, or environments that trigger your anxiety, and your therapist will guide you as you practice making the difficult but freeing choice not to perform the compulsion. Over time, this will help your brain learn that you are not in any real danger on account of your obsessions.

In OCD, you try so hard to avoid certain distressing thoughts or situations—to get rid of them—but that only gives them more power. Part of ERP therapy requires you to accept your fears and anxiety and learn to live with them. This takes away their power, so they’re not as loud anymore. In time, your OCD will no longer run the show.

In one meta-analysis and review of 24 randomized-controlled trials (the gold standard of research) on ERP concluded that this particular form of treatment was more effective compared to active therapy, medication, or placebo in reducing symptoms, per the Journal of Obsessive-Compulsive and Related Disorders in 2021. “According to these findings, ERP should be considered the treatment of choice for OCD,” said the study researchers.

If you’re experiencing particularly debilitating conditions like OCD or PTSD, it’s normal to feel mixed emotions when approaching treatment. “Patients are always reluctant, on one hand. On the other hand, they’re also excited to find someone who can provide the right treatment,” Dr. McGrath says. “A big piece of our success as therapists is motivating people to do the tough stuff. It’s not a snap of the fingers, you have to do the hard stuff in order to get through it.”