PTSD and OCD are two distinct mental conditions in the psychiatric literature, but is there any similarities or a connection between them? These two disorders can often be comorbid with one another, and symptoms can overlap in some cases. This article will go over how they might be related as well as discuss what treatment methods can work for both of them.
Intrusive thoughts are any unwanted ideas, words, or images that are invasive to a person's mind. They are unwelcome and can often cause distress to the individual experiencing them. However, depending on the condition, they can be slightly different.
In PTSD, intrusive thoughts often take the form of flashbacks, and are based on a previous traumatic event. Flashbacks are debilitating for people with PTSD because they can be spontaneous, or they can be triggered by specific stimuli. The mental images in flashbacks can be very realistic and can make a person feel like they are reliving their traumatic experience, which can also lead to them reacting to it and having real physiological responses.
Additionally, they can also be the subject of a person's nightmares, leading to sleep issues. 
For someone with PTSD, the smell of smoke and fire might trigger a war veteran to have flashbacks because it reminds him or her of past trauma in battle. In response to it, he or she might try hiding or start yelling, as if the event was truly happening. The veteran may look visibly stressed out with an elevated heart rate and blood pressure and sweating profusely.
On the other hand, intrusive thoughts in OCD work a little differently and do not necessarily need to involve any trauma whatsoever.
In OCD, intrusive thoughts can be a variety of subject matters that people find disturbing, and they can have multiple ones. These mental images can evolve into obsessions, and people with OCD will develop compulsions and rituals to respond to them and reduce the anxiety associated with the thoughts. 
For instance, a person might get an intrusive thought regarding contamination and disease, and to avoid contracting one, he or she will repeatedly wash his or her hands until they are absolutely certain that they are clean and free from any disease.
However, like PTSD, some OCD thoughts can also be triggered as well by certain events or hearing about something through the media or through word-of-mouth.
For example, a person might hear about a house burning down because the stove was left on. Later on, he or she will have an intrusive thought about their own home being on fire, and go back to check the stove and other appliances to make sure that it will not actually happen. This person knows that there is not a fire, but the thought of it occurring creates a response to it, known as a compulsion.
This can evolve into a recurring obsession, and while performing the compulsions gives reassurance, it also reinforces the illness, and the thoughts can show up very frequently. In response, they might develop irrational compulsions like checking over and over to make sure all appliances are off to ensure that everything will be fine.
Checking once or twice is reasonable, rational, and responsible behavior; however, repeating this compulsion several times to be certain that nothing bad will happen is indicative of OCD and can be very time-consuming and distressing. 
While people with OCD might realize that their intrusive thoughts are completely irrational, they are still uncertain and feel the need to check and make sure that things are safe and normal. This is why OCD is sometimes known as the "what-if disease."
Although these thoughts function differently in each illness, they are still intrusive and ultimately, lead to anxiety and distress.
Both Conditions Can Utilize Avoidance and Other Neutralizing Behaviors
In PTSD and OCD, people can frequently avoid the triggers for their intrusive thoughts so that they can go about their day without dealing with their symptoms.
Someone with PTSD can deliberately stay away from specific people, places, and things that remind them of their traumatic events, reducing the likelihood of being immersed in an intense flashback. However, some triggers can be impossible to avoid for many individuals.
For example, someone might avoid driving along the street and seeing the house that they grew up in because it will trigger unwanted memories of being abused.
In fact, avoidance symptoms are part of the diagnostic criteria for PTSD, and people must display at least 1 of them in order to receive a diagnosis from a doctor. 
Similarly, OCD suffers can display excessive avoidance behaviors as well and can go to great lengths doing so, and limit their quality of life.
Returning to the example earlier regarding the burning house, a person might avoid using the stove entirely so that it makes it virtually impossible for a catastrophic event to happen. Over time, they will also have an attached fear to using it as well as the original thought of the house catching on fire.
Repetitive and compulsive behaviors, including avoidance, can become instilled habits and when experiencing an intrusive thought, the person will naturally gravitate towards using these learned actions because it reduces anxiety and provides reassurance by neutralizing the thoughts. On the other hand, this also conditions fear and anxiety, and the person will resort to their habits to find a sense of normalcy. 
The same concept occurs in PTSD, and it is believed that avoidance behaviors are some of the most detrimental ones that people can perform because it makes fear stronger. At the same time, it impairs fear extinction, making it harder to become deconditioned to the triggers. In order for extinction to occur, the person must stop avoiding their triggers so that they can become desensitized to them. 
Although experiencing a traumatic event is necessary to get diagnosed with PTSD, it is not always the case for OCD; however, a devastating event can also contribute to OCD and cause it to surface.
For example, if a person was involved in a car accident that involved the fatality of another individual. That person can develop intrusive thoughts related to driving that happens every time he or she enters the vehicle. In order to neutralize these thoughts, this person tries to avoid driving on busy streets during peak times. They also sometimes repeatedly check to make sure they did not cause an accident.
In this situation, this person possibly has both PTSD and OCD, and symptoms of both conditions can overlap significantly.
Despite being in separate categories in the DSM-5, recent research suggests that they are on the same continuum and that there is a link between the two, and the symptoms can work off of each other. 
Studies show that when PTSD symptoms decrease, OCD symptoms increase, and as OCD symptoms are treated, PTSD symptoms take over. The OCD symptoms are not a replacement for the PTSD symptoms; instead, they are a coping mechanism for PTSD and their memories. 
In some situations, PTSD and OCD symptoms can be unrelated as well, yet still coexist at the same time and interact with one another.
There was one case involving a woman who was struggling to come to terms with her husband's cancer diagnosis. However, one month before that she experienced a stroke that hindered her quality of life and caused her to fear it. She then had textbook symptoms of PTSD such as hypervigilance, nightmares, insomnia, and flashbacks.
At the same time, she was also engaging in ritualistic and compulsive behavior. In order to prevent having another stroke, she felt the need to cough five times. Similarly, when taking her husband to the doctor's office, the woman would count the monitor's beeps in sets of five so that positive results could be produced. 
Because of case studies like these, some researchers have proposed that post-traumatic OCD should be considered as a separate condition. Nonetheless, it is still debated, and there is a lack of clear evidence at this time.
Although PTSD and OCD are technically different conditions, the research shows that they are much closer than some people think. From intrusive thoughts, avoidance behaviors, and the anxiety that comes with them, both can bring significant distress to a person.
Because they have similarities, treating both of them can involve similar protocols. A class of antidepressant drugs known as SSRIs (Selective Serotonin Reuptake Inhibitors) has been shown to provide relief to re-experiencing symptoms like flashbacks as well as the avoidance once. 
At the same time, SSRIs are a primary course of treatment for those with OCD. However, the effective dosage may be different for both conditions. OCD patients typically require a medium to a high dose of SSRIs in order to be therapeutic. 
Cognitive behavioral therapy (CBT) can also be extremely beneficial for those with OCD and PTSD because it addresses the person's thinking process and how they respond to triggers and other themes. CBT can change a person's fearful thoughts and reactions into ones that are productive and reduce the impact of the older ones.
At BetterHelp, online therapy is always available, and licensed professionals are eager to help you any time. If you have PTSD, OCD, or any mental health concern, assistance is just a click away. You are not alone and by having someone to talk to have and give you the coping skills that you need, you will be living the life you deserve, without fear.