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Deep dive into OCD and related disorders, focusing on the cycle of obsessions and compulsions.
What if your brain sent you a 'false alarm' so loud and persistent that you felt physically unable to ignore it, even if you knew it wasn't real?
Obsessive-Compulsive Disorder (OCD) is defined by a debilitating cycle of obsessions and compulsions. Obsessions are persistent, involuntary, and ego-dystonic thoughts (meaning they conflict with the person's self-image). These thoughts trigger intense anxiety. To alleviate this distress, the individual performs compulsions—repetitive behaviors or mental acts. This process follows a negative reinforcement model: the behavior is 'rewarded' by the temporary removal of anxiety, making the behavior more likely to occur again. Unlike everyday worries, these rituals are time-consuming (taking more than one hour per day) and significantly impair daily functioning.
1. Obsession: A student touches a doorknob and is hit with a sudden, intrusive thought: 'My hands are covered in deadly toxins.' 2. Anxiety: Their heart rate increases; they feel an overwhelming sense of dread. 3. Compulsion: They wash their hands exactly seven times using scalding water. 4. Relief: The anxiety drops temporarily, reinforcing the idea that 'washing saved me.'
Quick Check
In the OCD cycle, why does the person continue to perform the compulsion even if they know it is irrational?
Answer
Because the compulsion provides immediate, temporary relief from anxiety through negative reinforcement.
In a PET scan of an individual with OCD, you would likely see: 1. Increased glucose metabolism in the Orbitofrontal Cortex. 2. Hyperactivity in the Anterior Cingulate Cortex, which is involved in emotional response to errors. 3. This explains why the person feels 'something is wrong' even when logic says otherwise.
Quick Check
Which specific part of the brain acts as the 'filter' that fails in patients with OCD?
Answer
The Caudate Nucleus.
The DSM-5 categorizes OCD alongside related disorders that share the 'repetitive behavior' trait. Body Dysmorphic Disorder (BDD) involves a preoccupation with perceived physical flaws that are invisible to others, leading to mirror-checking or grooming rituals. Hoarding Disorder is characterized by persistent difficulty discarding possessions, regardless of value, due to a perceived need to save items. While OCD is often driven by a desire to prevent harm, Hoarding is often driven by an emotional attachment to objects or a fear of losing information, representing a different facet of the obsessive-compulsive spectrum.
Consider a patient who spends 4 hours a day skin-picking. 1. If they pick because they 'feel' germs on their skin, it is likely OCD. 2. If they pick to remove a 'hideous' mole that doctors say is invisible, it is likely BDD. 3. If they pick as a way to relieve general tension without a specific thought, it may be Excoriation Disorder.
Which of the following best describes an 'obsession'?
In the context of the CSTC circuit, what is the role of the Orbitofrontal Cortex (OFC)?
Hoarding Disorder is primarily driven by the same fear of contamination that drives most OCD cases.
Review Tomorrow
In 24 hours, try to sketch the four stages of the OCD cycle and name the three main components of the CSTC brain circuit.
Practice Activity
Find a case study of Body Dysmorphic Disorder online and identify the specific 'obsession' and the 'compulsive' ritual described.