Multifaceted Causes of Obsessive Compulsive Disorder

Obsessive compulsive disorder (OCD) is an anxiety disorder which is characterized by intrusive thoughts (obsessions) that result in worry and repetitive behaviors (compulsions) aimed at alleviating the anxiety. While most of us have run back into the house to check the stove was turned off, people suffering from OCD experience these thoughts more frequently, and to the point that it becomes alienating and all-consuming. But what causes it?

While the exact cause of OCD is not completely elucidated, researchers believe that it results from a combination of genetics and environmental factors. Genetic studies have linked a specific mutation in the serotonin transporter gene to the manifestation of OCD. Additional data from studies on identical twins have corroborated these results.

However, the studies also show that genetics accounts for only 40-65% of the risk for developing OCD, thus indicating that environmental factors also play a role in manifestation of the disease. Reports suggest the potential for a number of different environmental risk factors including strep infections, anxiety, emotional instability, depression, handwriting difficulties, behavioral aggression, and oppositional behaviors.

Differences in the physical structure of the brain are also a prominent factor in patients with OCD. In fact, neuroimaging techniques have revealed structural and volumetric abnormalities in the brains of these patients: People with OCD have a patterned increase in grey matter in the brain in certain areas and a decrease in others.

Other studies have examined the role for a potential chemical imbalance in the brain leading to disease symptoms. From a molecular perspective, data show that in fact neurotransmitter dysregulation does play an important role in the manifestation of OCD symptoms. More specifically, reports indicate that the neurotransmitters serotonin and dopamine are associated with the pathophysiology of OCD. Scientists show that patients with OCD may experience an increase in dopamine in the prefrontal cortex and/or a decrease in serotonin in the basal ganglia.

Currently used medications for managing the disorder including Clomipramine (Anafranil), Zluvoxamine (Luvox), Fluoxetine (Prozac), Paroxetine (Paxil, Pexeva), and Sertraline (Zoloft) specifically focus on regulating these neurotransmitter levels in the brain. Selective serotonin re-uptake inhibitors (SSRIs) decrease symptoms of OCD in two-thirds of adults and children who take them.

While there are a number of available medications for treating OCD symptoms, they come with unique risks. Similar to other psychological disorders, the choice of which mediation to use is often the result of trial and error, and drug interactions must be carefully considered. Furthermore, side effects may include an upset stomach, sleep disturbances, sweating, and a decrease in libido. It is hoped that additional research into the causes and molecular mechanism of OCD will ultimately lead to more effective and safe drugs for treating disease symptoms.


Cath, D., Grootheest, D., Willemsen, G., Oppen, P., & Boomsma, D. (2008). Environmental Factors in Obsessive-Compulsive Behavior: Evidence from Discordant and Concordant Monozygotic Twins Behavior Genetics, 38 (2), 108-120 DOI: 10.1007/s10519-007-9185-9

Harsányi A, Csigó K, Demeter G, & Németh A (2007). [New approach to obsessive-compulsive disorder: dopaminergic theories]. Psychiatria Hungarica : A Magyar Pszichiatriai Tarsasag tudomanyos folyoirata, 22 (4), 248-58 PMID: 18167420

Kim CH, Cheon KA, Koo MS, Ryu YH, Lee JD, Chang JW, & Lee HS (2007). Dopamine transporter density in the basal ganglia in obsessive-compulsive disorder, measured with [123I]IPT SPECT before and after treatment with serotonin reuptake inhibitors. Neuropsychobiology, 55 (3-4), 156-62 PMID: 17657168

Ozaki N, Goldman D, Kaye WH, Plotnicov K, Greenberg BD, Lappalainen J, Rudnick G, & Murphy DL (2003). Serotonin transporter missense mutation associated with a complex neuropsychiatric phenotype. Molecular psychiatry, 8 (11), 933-6 PMID: 14593431

Image via Milkovasa / Shutterstock.

  • Jay

    OCD is no longer classified as an anxiety disorder, according to the DSM V. It has its own chapter/spectrum in the DSM, which includes similar disorders such as body dysmorphic disorder and trichotillomania, hoarding disorder, and excoriation disorder.

    • Hi Jay! That’s really interesting. When was OCD not considered as Anxiety disorder? I would like to research on this. 🙂

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  • My own take on OCD is only mildly in line w DSM 5, a tome that almost completely ignores reality, context and cognitive function. I’ve been writing about cognitive anxiety for years over at CorePsych and will link this brief video to consider some of the important differences that exist between cognitive anxiety and affective anxiety.

    This vid resides in a playlist on these matters, and is a start on the essential conversation that begs for review in office applications.


    Dr Charles Parker
    Author: New ADHD Medication Rules – Brain Science & Common Sense

  • And, a footnote: Prozac may help a bit with cognitive anxiety, but it blocks 2D6 and thereby discourages any specific stimulant treatment for comorbid ADHD.

    A video on that issue:

    Thanks again,

  • I can fully relate as I lived in agony for 40 years with anxiety, depression, panic attacks and a destroyed sense of self and identity. I wish that every person afflicted with these inner struggles to find peace and happiness and a way to control the emotions and behaviors associated with them. For those interested, I have a simple blog up with my experiences and my story, along with a few reviews of products/techniques that have helped me in my quest to find solutions. I sincerely want to spread the word about what helped me because after so many doctors and so many types of medicine I was at the point of believing nothing was ever going to help. I’m happy to share my story and hope it may help others! My blog can be found at :

    Many blessings to all!

  • A thorough post on the subject of OCD. Many thanks for sharing this information with us.

  • I don’t think any discussion about OCD is complete without mentioning that Exposure and Response Prevention (ERP) Therapy, a type of Cognitive Behavioral Therapy, is the front line treatment for the disorder. My son had OCD so severe he could not even eat and this therapy literally saved his life. He is now a college graduate living life to the fullest. OCD, no matter how severe, is treatable. I talk about anything and everything to do with the disorder on my blog at:

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  • Tammi Lutz(14298270)

    I, myself am an OCD sufferer,
    and I can easily confirm all the above information and comments.
    This disorder is a nuisance and my life greatly.
    I would like to share some knowledge u recently received from a psychologist in treating the disorder, and if anyone wants to give it a try, i would love feedback!
    The most effective methods i’ve come into contact with, is literally fighting the compulsions.
    One of my Obsessions is rewriting my work over and over again, only writing in pencil and erasing single letters that stick out as messy or “imperfect”.
    I was told that everytime I feel the urge to erase a messy letter, i must fight the compulsion to erase and fight the anxiety.
    Starting with the most miner obsessions and working my way up to my biggest worries.
    It is clearly evident that this is an effective technique for me, i wonder if it works in all or maybe even most OCD cases.

Norell Hadzimichalis, PhD

Norell Hadzimichalis, PhD, is a trained molecular biologist with postdoctoral research experience in a prominent neuroscience laboratory. She holds a PhD in Molecular Biology from The University of Medicine and Dentistry of New Jersey. She has authored and co-authored multiple peer reviewed research and review articles in journals including Schizophrenia Research, Brain Research, and the Journal of Neuroscience. Her current interests are in commercializing basic scientific findings and exploring methods of moving research from the benchside to the bedside.

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