Causes and Related Disorders

It was the general belief in the 14th and 15th centuries that those who experienced blasphemous, sexual, or other obsessive thoughts were possessed by the devil. Based on this reasoning, treatment involved banishing the evil from the possessed patient through exorcism. Advances in science have allowed many disorders to be better understood in both physiological and psychological terms. However, though more is now known regarding the psychological aspect of obsessions and compulsions, the definitive cause of OCD is still unknown.

In the early 1900s, Freud attributed obsessive-compulsive behavior to unconscious conflicts which manifested as symptoms. Even more recently, OCD was linked to stressors or traumas that occurred during childhood (e.g. bad parenting, family problems, being bullied). Subsequent research into this disorder, however, has provided evidence to support the theory that OCD is a biological problem.

There are many different theories about the cause of obsessive-compulsive disorder. Some research has discovered a type of size abnormality in different brain structures. The majority of researchers believe that there is some type of abnormality in the neurotransmitter serotonin, among other possible psychological or biological abnormalities; however, it is possible that this activity is the brain's response to OCD, and not its cause. Serotonin is thought to have a role in regulating anxiety, though it is also thought to be involved in such processes as sleep and memory function. This neurotransmitter travels from one nerve cell to the next via synapses. In order to send chemical messages, serotonin must bind to the receptor sites located on the neighboring nerve cell. It is hypothesized that OCD sufferers may have blocked or damaged receptor sites that prevent serotonin from functioning to its full potential. This suggestion is supported by the fact that many OCD patients benefit from the use of Selective Serotonin Reuptake Inhibitors (SSRIs) — a class of antidepressant medications that allow for more serotonin to be readily available to other nerve cells.

Recent research has revealed a possible genetic mutation that could be the cause of OCD. Researchers funded by the National Institutes of Health have found a mutation in the human serotonin transporter gene, hSERT, in unrelated families with OCD. Moreover, in his study of mono zygotic twins, Rasmussen produced data that supported the idea that there is a “heritable factor for neurotic anxiety”. In addition, he noted that environmental factors also play a role in how these anxiety symptoms are expressed. However, various studies on this topic are still being conducted and the presence of a genetic link is not yet definitely established.

Technological advancements have allowed for the possibility of brain imaging. Using tools like positron emission tomography (PET scans), it has been shown that those with OCD tend to have brain activity that differs from those who do not have this disorder. This suggests that brain functioning in those with OCD may be impaired in some way. A popular explanation for OCD is that offered in the book 'Brain Lock' by Jeffrey Schwartz, which suggests that OCD is caused by the part of the brain that is responsible for translating complex intentions (e.g., "I will pick up this cup") into fundamental actions (e.g., "move arm forward, rotate hand 15 degrees, etc.") failing to correctly communicate the chemical message that an action has been completed. This is perceived as a feeling of doubt and incompleteness which then leads the individual to attempt to consciously deconstruct their own prior behavior — a process which induces anxiety in most people, even those without OCD.

It has been theorized that a miscommunication between the orbital-frontal cortex, the caudate nucleus, and the thalamus may be a factor in the explanation of OCD. The orbital-frontal cortex (OFC) is the first part of the brain to notice whether or not something is amiss. When the OFC notices that something is wrong, it sends an initial “worry signal” to the thalamus. When the thalamus receives this signal, it in turn sends signals back to the OFC to interpret the worrying event. The caudate nucleus lies between the OFC and the thalamus and it prevents the initial worry signal from being sent back to the thalamus after it has already been received. However, it is suggested that in those with OCD, the caudate nucleus does not function properly, and therefore does not prevent this initial signal from recurring. This causes the thalamus to become hyperactive and creates a virtually never-ending loop of worry signals being sent back and forth between the OFC and the thalamus. The OFC responds by increasing anxiety and engaging in compulsive behaviors in an attempt to relieve this apprehension.

Violence is rare among OCD sufferers, but the disorder is often debilitating and detrimental to their quality of life. Also, the psychological self-awareness of the irrationality of the disorder can be painful. For people with severe OCD, it may take several hours a day to carry out the compulsive acts. To avoid perceived obsession triggers, they also often avoid certain situations or places altogether.

It has been alleged that sufferers are generally of above-average intelligence, as the very nature of the disorder necessitates complicated thinking patterns, but this has never been supported by clinical data.

People with OCD may be diagnosed with other conditions, such as Tourette syndrome, compulsive skin picking, body dysmorphic disorder and trichotillomania. It is also interesting to note that there is some research demonstrating a link between drug addiction and obsessive compulsive disorder as well. There is a higher risk of drug addiction among those with any anxiety disorder (possibly as a way of coping with the heightened levels of anxiety), but drug addiction among obsessive compulsive patients may serve as a type of compulsive behavior and not just as a coping mechanism. Depression is also extremely prevalent among sufferers of OCD. One explanation for the high depression rate among OCD populations was posited by Mineka, Watson and Clark, who explained that people with OCD (or any other anxiety disorder) may feel depressed because of an "out of control" type of feeling. There may also be a link between autism and Asperger syndrome and OCD.

Some cases are thought to be caused at least in part by childhood streptococcal infections and are termed P.A.N.D.A.S. (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections). The streptococcal antibodies become involved in an autoimmune process. Though this idea is not set in stone, if it does prove to be true, there is cause to believe that OCD can to some very small extent be “caught” via exposure to strep throat (just as one may catch a cold). However, if OCD is caused by bacteria, this provides hope that antibiotics may eventually be used to treat or prevent it.

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