Understanding OCD: Prevalence, Causes, Types, and Treatment

Obsessive-Compulsive Disorder (OCD) is characterized by intrusive repetitive thoughts and uncontrollable behaviors. Obsessions and compulsions often interfere with daily activities, causing stress and leading to daily disruptions. OCD is often a life-long disorder that requires ongoing treatment.

What is OCD?

  • Obsessions (O): Defined as thoughts, images, or urges that are persistent and intrusive. These mental experiences are not voluntary, and the individual cannot control them at will. The obsessions often are cyclic, involving more than one act or thought, which appears in a sequence and causes anxiety or distress. An individual suffering from OCD will attempt to neutralize the obsessions by a different mental act, such as a thought or another action, leading to a compulsion.
  • Compulsions (C): Belief that one can escape compulsions through repetitive behaviors or mental acts. These can be rituals performed with great detail in a particular way to achieve completion. Compulsive behaviors or mental acts are usually associated with an obsession, like obsessively fearing getting sick or contracting a disease, that will lead to hygiene rituals used to relieve anxiety. Compulsions can also be incomplete, meaning an individual repetitively performs them until deeming them done to perfection.
  • Distorted behavior (D): These are often extreme behaviors. For example, everyone washes their hands to prevent illness, but with OCD, an individual takes it to the extreme, such as washing hands after touching anything or washing them for a prolonged period. With OCD, behaviors are not performed for pleasure, even though one can achieve this by relieving anxiety or distress.


OCD often is diagnosed during childhood or early adolescence, and is chronic, meaning it persists throughout one's lifetime. The life-long prevalence of OCD worldwide is slightly above 1%, more specifically 1.5% for women and 1% for men. Even though women tend to be affected at a higher rate, men often receive earlier diagnoses. The prevalence of OCD varies based on culture. For example, the United States is almost double the worldwide percentage at 2.3%. The cross-sectional frequency, which is the prevalence at a specific point in time, is lower; however, OCD has low rates of lifelong remission, meaning it's likely someone with OCD will relapse.

OCD is highly likely to co-occur with other psychiatric disorders. Up to 76% of OCD patients have a history of or are co-currently diagnosed with another anxiety disorder, such as social anxiety disorder, phobias, and generalized anxiety disorder. Slightly less common, 63% suffer from mood disorders, and around a third may suffer from an obsessive-compulsive personality disorder (OCPD). It's important to realize that OPCD and OCD are different diagnoses. To a lesser degree, OCD is commonly a secondary diagnosis in people suffering from neuropsychological disorders, such as Schizophrenia, Bipolar Disorder, eating disorders such as Anorexia Nervosa, and Tourette disorder. It is common to assess an individual for OCD if one receives any of the above diagnoses.


While there is no set cause for developing OCD, the literature suggests that hereditary and environmental factors play a role in the onset of the illness. It is important to note that research on causes is ongoing, with most efforts focusing on the cortico-striato-thalamo-cortical (CSTC) circuit in the brain.

The known causes can be categorized as:

  1. Genetics: Studies done on twins suggest a genetic component of OCD. It is more pronounced in the early onset OCD, which is the childhood diagnosis of OCD, than the late OCD, the adult diagnosis of OCD. The specific genes involved in OCD are unknown, but it is a rapidly developing area of research.
  2. Environment:
  • Stress: A traumatic event, followed by psychological and mental stress
  • Trauma: Brain injury, or ischemic stroke, especially those affecting the areas of the cortico-striatal-thalamo-cortical
  • Hormonal fluctuations: Premenstrual and postpartum periods are associated with OCD relapse

In addition, the following factors have also been linked to OCD:

  • Neurobiology: A large body of literature indicates that the structure and function of the CSTC pathway in the brain is the prime suspect for causing OCD. The CSTC circuit is involved in controlling movement execution, habit formation, and reward.
  • Animal models: Surgically altering the CSTC circuit in animals produces OCD-like symptoms.
  • Structure: Neuroimaging studies have shown structural abnormalities in the orbitofrontal cortex, anterior cingulate cortex, and striatum.
  • Function: Functional neuroimaging studies have shown that when performing cognitive tasks, patients with OCD recruit CSTC circuits differently than healthy individuals.


Types of OCD are broadly categorized into 5 themes, based on the present obsessions and compulsions. Hoarding is diagnosed as a separate disorder, but it sometimes plays a role in OCD. The symptomatology and severity of symptoms vary between individuals.

  • Contamination: Fear of contamination, dirt, and germs leading to compulsively washing, showering, and cleaning.
  • Responsibility for harm/mistakes: Thoughts or images of harming oneself or others, leading to checking compulsions. This means focusing attention on a physical object for reassurance.
  • Unacceptable thoughts: Intrusive aggressive, sexual, religious thoughts that lead to mental rituals, such as praying.
  • Incompleteness: Fear of asymmetry or concerns of symmetry, resulting in repeating, counting, ordering, and straightening.
  • Hoarding: Sometimes found in OCD patients, it involves obsessively collecting, hoarding behaviors.


If you suspect you may suffer from OCD, seek help from your doctor. The following tools can help practitioners diagnose OCD.

  • Psychological evaluation: Involves discussing thoughts, feelings, symptoms, and behaviors to determine if obsessive or compulsive behaviors exist and interfere with daily life.
  • Diagnostic criteria: Criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association, may be used.
  • Physical exam: This determines whether a different issue could be causing symptoms.


Proper treatment can control your symptoms and prevent them from interfering with daily life. The OCD severity will determine the extent of treatment and whether it needs to be ongoing. There are two main treatment types:

  1. Psychotherapy: Cognitive behavioral therapy (CBT) and exposure and response prevention (ERP)
  2. Medications:
  • Clomipramine (Anafranil)
  • Fluoxetine (Prozac)
  • Fluvoxamine
  • Paroxetine (Paxil, Pexeva)
  • Sertraline (Zoloft)

Other treatment options include:

  • Intensive outpatient and residential treatment programs
  • Deep brain stimulation (DBS)
  • Transcranial magnetic stimulation (TMS)

Discuss pros and cons of each treatment plan with your doctor, so you understand how each may affect you.

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