Obsessive-Compulsive Disorder

  • Basics

    Obsessive-compulsive disorder (OCD) is a psychiatric disease characterized by obsessions, repetitive (usually unpleasant) thoughts and compulsions, and ritualistic behaviors. Obsessive-compulsive disorder (OCD) usually starts in childhood or early adulthood. It is characterized by anxiety-provoking thoughts, images, or ideas (obsessions) and/or ritualistic behaviors such as counting, repeated checking, or handwashing (compulsions). People with OCD engage in compulsive behaviors to try to rid themselves of disturbing obsessive thoughts.

    Symptoms can usually be brought under control with medications or behavioral therapy. Even with appropriate treatment, most people with the disorder experience symptoms that wax and wane throughout life.

    OCD is the fourth most common psychiatric disorder after phobias, substance abuse, and major depression. In the US, 1% to 2% of the population suffers from OCD. Most people experience their first symptoms around age 20. Few people have an initial episode of OCD after the age of 35.

  • Causes

    While the exact cause of OCD is unknown, in some cases genetics may be involved. If you have a close relative with OCD, you are more likely to develop OCD yourself Table 01.

    Table 1.  Possible Causes of OCD

    Genetics
    Infection (e.g. streptococcal infection, von Economo's encephalitis, Sydenham's chorea)
    Lesions in specific areas of the brain
    Oversensitive or malfunctioning brain circuits
    Head trauma (occasionally)
    Brain tumor (in rare cases)
    Drug effects
    Anxiety
    Issues of control, aggression, and sexuality resulting from excessively strict parenting

    A small percentage of children develop OCD after a streptococcal infection. Sometimes after a streptococcal infection, a child's immune system will attack normal healthy cells (autoimmune response). It is thought that this response causes OCD symptoms. An episode of OCD that begins this way may disappear within a few months, or may persist longer.

    People with OCD have abnormal levels of brain chemicals and abnormal activity in certain areas of the brain Figure 01. Certain areas of the brain that are associated with anxiety, habit formation, and skill learning (called the limbic lobe, the caudate nucleus, and the orbital frontal cortex) are abnormal in people with OCD.

    In addition, levels of the brain chemical serotonin are thought to be responsible for OCD. Most medications used to treat OCD have an effect on serotonin levels.

    Some theories point to psychological reasons for OCD.

    Click to enlarge: Areas of Abnormal Brain Activity in OCD

    Figure 01. Areas of Abnormal Brain Activity in OCD

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