Despite a wealth of research, the exact causes of obsessive-compulsion disorder (OCD) have not been identified.
OCD is thought to have a neurobiological basis, with neuroimaging studies showing that the brain functions differently in people with the disorder.
An abnormality, or an imbalance in neurotransmitters, is thought to be involved in OCD.
The disorder is equally common among adult men and women.
OCD in Children
OCD that begins in childhood is more common in boys than girls, with the usual time of onset of OCD later for females than males.
The condition might be triggered by a combination of:
- Genetic;
- Neurological;
- Behavioural;
- Cognitive; and
- Environmental factors.
Genetic Causes
OCD runs in families and can be considered a “familial disorder.”
The disease may span generations with close relatives of people with OCD significantly more likely to develop OCD themselves.
Twin studies of adults suggest that obsessive-compulsive symptoms are moderately able to be inherited, with genetic factors contributing 27 to 47% variance in scores that measure obsessive-compulsive symptoms.
However, no single gene has been identified as the “cause” of OCD.
Autoimmune Causes
Some rapid-onset cases of OCD in children might be consequences of Group A streptococcal infections, which cause inflammation and dysfunction in the basal ganglia.
These cases are grouped and referred to as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS).
In recent years, however, other pathogens, such as the bacteria responsible for Lyme disease and the H1N1 flu virus, have also been associated with the rapid onset of OCD in children.
As such, medical professionals have altered the acronym to PANS, which stands for Paediatric Acute-onset Neuropsychiatric Syndrome.
Behavioural Causes
The behavioural theory suggests that individuals with OCD associate certain objects or situations with fear. They learn to avoid those things or learn to perform “rituals” to help reduce the fear.
This fear and avoidance or ritual cycle may begin during a period of intense stress, such as when starting a new job or just after an important relationship comes to an end.
Once the connection between an object and the feeling of fear becomes established, individuals with OCD begin to avoid that object and the fear it generates, rather than confronting or tolerating the fear.
Cognitive Causes
The behavioral theory outlined above focuses on how individuals with OCD make an association between an object and fear. The cognitive theory, however, focuses on how individuals with OCD misinterpret their thoughts.
Most individuals have unwelcome or intrusive thoughts at certain times, but for individuals with OCD, the importance of those thoughts are exaggerated.
For example, an individual who is caring for an infant and who is under intense pressure may have an intrusive thought of harming the infant either deliberately or accidentally.
Most individuals can shrug off and disregard the thought, but a person with OCD may exaggerate the importance of the thought and respond as though it signifies a threat. As long as the individual with OCD interprets these intrusive thoughts as cataclysmic and true, they will continue the avoidance and ritual behaviours.
Neurological Causes
Brain imaging techniques have allowed researchers to study the activity of specific areas of the brain, leading to the discovery that some parts of the brain are different in individuals with OCD when compared to those without.
Despite this finding, it is not known exactly how these differences relate to the development of OCD.
Imbalances in the brain chemicals serotonin and glutamate may play a part in OCD.
Environmental Causes
Environmental stressors may be a trigger for OCD in individuals with a tendency toward developing the condition.
Traumatic brain injury (TBI) in adolescents and children has also been associated with an increased risk of onset of obsessive-compulsions. One study found that 30% of children aged 6 to 18 years who experienced a TBI developed symptoms of OCD within 12 months of the injury.
Overall, studies indicate that individuals with OCD frequently report stressful and traumatic life events before the illness begins.
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