OCD vs. Delusional Disorder vs. Schizophrenia

by Kevin Foss, MFT

When discussing Obsessive Compulsive Disorder (OCD), we often use phrases to describe the obsessional piece as “intrusive thoughts” or “distorted thinking” or “irrational beliefs.” Many OCD sufferers fear that their intrusive, irrational obsessions are signs that they are “crazy” or will “go crazy.” But, how does this differ from Delusional Disorder? Similarly, how does this differ from Schizophrenia? This article will discuss the differences between OCD vs. Delusional Disorder vs. Schizophrenia.

What is Obsessive Compulsive Disorder?

Obsessive Compulsive Disorder, or OCD, is an anxiety disorder that attacks the sufferer with unwanted and intrusive thoughts, feelings, images, sensations, or urges that produce an overwhelming sense of doubt, uncertainty, and fear. The obsessions often revolve around specific themes, such as Harm OCD, Contamination, Sexual Orientation OCD, or Scrupulosity, just to name a few. Of course, someone can experience several themes at once, or just experience a single theme. OCD sufferers can also experience just one consistent obsession over time, or struggle with changing or switching obsessions throughout their life.

Along with obsessional doubts, people living with OCD feel obligated to engage in compulsive behaviors and rituals in order to alleviate their doubt, neutralize the unwanted feeling, or avoid the feared outcome. These behaviors can be overt, meaning they are observable by others, or they can be covert, meaning the rituals or routines are done internally. Covert compulsions are the basis for the Purely Obsessional, or Pure O, subtype where the compulsions present as continued thinking or “obsessing” but are ultimately ruminative or neutralizing cognitive tasks that amount to compulsions.

Door left slight open
Obsessing over whether someone has shut or locked a door completely is another common OCD obsession

Common OCD Themes:

  • What if I didn’t lock my car door?
    • I need to line up my books properly or I might fail my class.
    • If I don’t pray in just the right way and in the right order, I might offend God and be sent to Hell.
    • Am I in the right relationship? Do I truly love my partner, or would I be happier with someone else?
    • If I don’t change my clothes and shower immediately when I get home, my whole family could get sick and it would be my fault.
    • What if I actually harmed my co-worker and don’t remember it.
    • Did I actually do something horrible in high school that could be found out by others and ruin my life?

    What is Delusional Disorder?

    Delusional Disorder is a mental health disorder marked by a prolonged period of irrational and firmly held beliefs. A delusion is a thought or belief that is not shared or held by the vast majority of other people, yet the individual continues to assert their faith that the thought is true.

    Delusional Disorder can range from non-bizarre to bizarre in nature. Non-bizarre thoughts are not completely outside of the realm of possibility, yet are still highly unlikely. For example, believing that someone has extraordinary skill that will lead to wealth and fame, believing that others are trying to destroy one’s reputation, or believing that someone is in love with them despite having no evidence are all ways someone can have non-bizarre delusions.

    Person with donkey head in a large crowd of uniformed military school students.
    Many people with OCD feel like they are the only one experiencing their feelings and thoughts, whereas someone with Delusional Disorder may think that more people should share their same thoughts and feelings.

    Bizarre delusions are beliefs that are well outside of the rational and boarder on the ridiculous. Examples include believing aliens have infiltrated the government, believing that one has powers to control the weather, or believing that they have a brain tumor without medical evidence.

    Delusions are often believed as forgone conclusions and it is very difficult to dissuade someone from their belief or convince them they may be wrong. To that end, delusions generally do not cause the believer much distress outside of the distress that their belief is true. The family, friends, and acquaintances surrounding the believer usually experiences the most distress as they struggle deal with and interact with the irrational belief from their rational perspective.

    What is Schizophrenia?

    While someone with Delusional Disorder can typically function normally in society along-side others without delusional thinking, someone with Schizophrenia has a much harder time dealing with their disorder.

    Schizophrenia is another mental health disorder that can include delusional thinking or beliefs, but is marked by a pattern of disrupted thinking processes, difficulty in social interactions, emotional disruption, and disordered sensory perception.

    Schizophrenia symptoms also include:

    • Hallucinations, such as hearing voices, seeing people or objects that aren’t there, or erroneously perceiving physical sensory input.
    • Scattered thinking or disorganized speech
    • Flattened or blunted emotional expression
    • Physical or cognitive impairment
    • A gross misperception of reality

    How Does OCD Differ From Delusional Disorder and Schizophrenia?

    With that brief overview of OCD, Delusional Disorder, and Schizophrenia, you may already start to see some of the differences between them. Now we will go into greater detail by looking at some key differences between the disorders to see what sets them apart from one another.

    View of a man's reflection in a pool of water.
    Schizophrenia is like viewing the world from an entirely different perspective of reality than others, not just having a unique take on life.

    First, we’ll see how the presence or absence of rational and irrational thinking differentiate the disorders and how it impacts the individual’s functioning. Next, we’ll see how OCD can be seen as a primarily anxiety based disorder, and while the other two may have anxiety associated with them, their other symptoms go beyond that of the typical OCD diagnostic criteria. We’ll take a look at the role doubt plays within the disorders and how OCD thrives in doubt, yet is easily toppled in moments of clarity or genuine self reflection. Finally, we will take a look at OCD compulsions and how their existence are a defining feature of the disorder and the key to overcoming OCD.

    Rational Vs Irrational Thinking

    There is an old, insensitive joke about OCD that originates from Dr. Jonathan Greyson. It goes like this: What’s the difference between someone with OCD and someone who’s crazy? The person with OCD knows they are crazy.

    While you might bristle at the use of the word “crazy,” the joke illustrates several very import distinctions between OCD and other disorders.

    It illustrates that people, generally, have two sides of their thinking; a rational/ logical side, and an irrational/ fear-based side. Someone with Delusional Disorder or Schizophrenia are looking at the word only from their irrational/ fear-based side. Their delusional beliefs are perceived as facts and are not disputed or balanced. They are the way that it is.

    On the other hand, people with OCD have both their rational and fear-based sides intact. While they will experience overwhelming anxiety and distorted thinking, they also can acknowledge their rational understanding that their fear is exaggerated, distorted, and irrational. This logical acknowledgement may be deep, deep down or simply brushed aside by the “better safe than sorry” justification, but someone with OCD is able to recognize that their obsessions are based in a false and exaggerated reality.


    Another important distinction between OCD and these other disorders is the presence of anxiety as a primary response to the belief. 

    As discussed above, the response to the delusional thinking of both Delusional Disorder and Schizophrenia is usually one of matter-of-fact and acceptance as reality. When the belief is understood as fact, the resulting odd behavioral response is entirely justified as the fundamental understanding of reality and truth is different for the person experiencing delusions.

    Man walking. OCD vs. Delusional Disorder vs Schizophrenia.
    OCD vs. Delusional Disorder vs. Schizophrenia. Seeing the world differently is not a diagnosis by itself.

    Conversely, in response to the obsessive doubt, someone with OCD experiences a tremendous sense of anxiety, fear, and uncertainty that drives the urge for compulsive behaviors to regain emotional or intellectual safety. The difference is that the obsession calls into question something they believe to be true about the world, themselves, or others which creates a sense of dissonance that drives the sufferer to disprove the obsession, prove what they believe is actually true, or achieve a sense of emotional peace through behavioral or mental avoidance or neutralization.


    Another central component of OCD that sets Delusional Disorder and Schizophrenia apart is the presence of doubt and uncertainty.

    OCD is often called “the doubting disease” for good reason. It calls into question one’s perception of reality. It can do this by asking the question “what if you didn’t wash your hands enough” or “if you didn’t fully shut off the water tap you could flood and destroy your whole apartment complex,” or it can do it by making a blanket statement like “I’m gay,” or “You should break up with your partner.”

    With either means of attack, the OCD suffer does not generally take it as fact and move on with their life with new outlook on the world. Instead, they respond by defending their desired beliefs, character, safety of others, or understanding of the world through their compulsive means.

    Sometimes, for example, I’ll hear clients say, “But the obsessive thought isn’t a question, it’s a fact! I thought ‘I’m gay’ so that’s got to mean that I’m gay!” However, in their heart of hearts they don’t truly think this is true because they engage in compulsions to disprove this notion and ensure they are indeed straight.

    Delusions are perceived and treated as fact. The influencer on Tik Tok loves me. Yes. I’m the greatest guitar player to ever live. Of course. The earth is flat. Absolutely. Cthulhu is inserting thoughts into my head and making me think about my cousin in a tutu. Obviously.

    Woman sitting on her bed hands folded in prayer.
    Compulsive prayer is a common obsession for OCD used to neutralize anxiety.


    The final difference is the presence of compulsive behaviors. Compulsions can be overt, i.e. outward and physical, or covert, i.e. internal and mental. They are seemingly obligatory acts in order to make right an emotional or cognitive wrong.

    It is sometimes said that without compulsions, OCD would not exist. It would just be thoughts. This statement is absolutely true because the presence of unwanted intrusive thoughts, feelings, mental images, physical sensations, or urges is natural and part of having a human brain. However, the misplaced anxious response discussed earlier and the compulsive behaviors are what make it a disorder and outside the typical experience.

    Delusional Disorder and Schizophrenia do not include compulsive behaviors as part of their diagnostic criteria. Additionally, the function of the subsequent behavior to the antecedent thought or belief is entirely different than the behavioral function of OCD-based compulsions. The response instead is a reflection of new rules of play rather than against the proposed rules.


    Obsessive Compulsive Disorder, Delusional Disorder, and Schizophrenia are three very distinct diagnoses with small overlapping similarities that sometimes cause a tremendous amount of anxiety and angst among some OCD sufferers. However, through our discussion of the three disorders, we can see that the core symptoms, emotional experience, and behavioral response shows that the disorders should be considered entirely different and separate. Furthermore, the discussion of the four primary differences of rational vs irrational thinking, anxiety, doubt, and compulsions helps to show how OCD sufferers can firmly anchor themselves in this diagnosis and resist further rumination or speculation about their diagnosis and applicable treatment.

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    To learn more about Obsessive Compulsive Disorder treatment, or to schedule a consultation about online or in-person treatment with The California OCD and Anxiety Treatment Center, please contact us here, or call us at (714) 423-3779

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