The Link Between OCD and Major Depressive Disorder

Challenges in Managing the Dual Diagnosis

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People with obsessive-compulsive disorder (OCD) are at a greater risk of developing other forms of mental illness. One of the most common is major depressive disorder (MDD).

In fact, research suggests that as many as two-thirds of people living with OCD will experience a major depressive episode sometime during the course of their illness. The causes can be varied, ranging from a reactive stress to obsessive or compulsive behaviors to biochemical changes in the brain that can alter moods and behavior.

Depression can be especially serious in people with OCD as it can affect their ability to adhere to the treatment of their OCD symptoms.

Understanding Major Depressive Disorder

Major depressive disorder is about more than just feeling sad. To be diagnosed with MDD, you need to experience a depressed mood and lose interest in things that used to be enjoyable to you for at least two weeks. In addition,  four of the following symptoms must be present nearly every day during the same two-week period:

  • Eating too much or too little
  • Sleeping too much or too little
  • Feeling either slowed down or noticeably fidgety
  • Having low energy
  • Having feelings of worthlessness or inappropriate guilt
  • Difficulty thinking or concentrating
  • Having recurrent thoughts of death or suicide

Typically speaking, these symptoms will be severe enough to cause trouble at home or work.

How OCD and Depression Are Related

Depression in people with OCD most often occurs after the onset of OCD symptoms. What this suggests that the depression may be related to the personal stress of living with OCD or troubles that have developed at home or work as the result of the disease.

Scientists also believe there may be biochemical factors that contribute to the depression. We know, for example, that OCD and MDD are both characterized by changes in the production and activity of serotonin, a chemical which relays signals between nerve cells. With these biochemical changes can come associative behavioral ones, some of which are shared in people with OCD and MDD. As such, OCD may perpetuate MDD simply by enhancing an underlying biochemical imbalance.

Most evidence also suggests that symptoms of depression are more actively linked to disturbing obsessions (negative thoughts you can't get rid of) rather than to compulsions (repetitive behaviors you can't control).

Complications in Managing the Dual Diagnosis

On their own, OCD and MDD require specific care and treatment delivered over the long term. When they both occur together, they can complication therapy and require a specialist trained in treating the dual diagnosis.

But this is really only the tip of the problem. By its very nature, major depression tends to affect a person's ability to maintain adherence to a drug therapy, not only those related to OCD but any chronic medication that requires daily drug-taking.

Oftentimes, feelings of persistent hopelessness can lead people to ask "what's the point?" If this happens, the person will usually be less interested in taking their drugs, grooming, eating properly, or interacting with others.

This can be seriously problematic for those undergoing OCD treatment. Insofar as many psychotropic drugs requires high levels of adherence to achieve the desired effect, any gap in treatment can take back the gains a person may have made. To mitigate this concern, the therapist will often need to treat the depression first before addressing the OCD.

On the other hand, the use of selective serotonin reuptake inhibitors (SSRIs), commonly used to treat depression, is also known to be effective in managing many of the symptoms of OCD.

In the end, if you have been diagnosed with OCD and believe you have depression, do not wait for the feelings of sadness to pass. Speak with your doctor or mental health provider. Treatment plans can be adjusted to meet your needs and prevent the worsening of symptoms.

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  • Pallatini, S.; Grassi, G.; Sarrecchia, E. et al. "Obsessive–Compulsive Disorder Comorbidity: Clinical Assessment and Therapeutic Implications." Front Psychiatry. 2011; 2:70. DOI: 10.3389/fpsyt.2011.00070.
  • Remijnse, P.; van den Heuvel, O.; Nielen, M. et al. "Cognitive Inflexibility in Obsessive-Compulsive Disorder and Major Depression Is Associated with Distinct Neural Correlates." PLoS One. 2013; 8(4): e59600. DOI: 10.1371/journal.pone.0059600.