What is OCD?
OCD is one of the most commonly occurring mental health disorders. It affects about 1% to 2% percent of Western general populations. It is characterized by recurring powerful thoughts that are very hard to prevent or control (the obsessions). These lead to irresistible and recurring behaviors (the compulsions) (1-3). Compulsions are actions taken to negate or resolve the disruptive, anxiety provoking and disturbing thoughts. A familiar example are those individuals so fearful of “contamination” from everyday activities, such as using a keyboard, touching a doorknob, or handling a notebook, that they feel compelled to scrub their hands with soap and water or a disinfectant many dozens of times a day and despite raw skin from the cleansers. Other unwanted obsessive thoughts can have more disturbing and aggressive themes. Intrusions may occur so frequently that they disrupt personal relationships, work, sleep and almost all other aspects of daily life.
Many people experience troubling, unwanted thoughts at one time or another (4). However, in those without OCD, these thoughts are given little importance, do not necessarily compel any actions, and readily disappear (2-4). By comparison, in those with OCD, the thoughts or impulses are intense, relentless and can cause tremendous anxiety, guilt, and disgust. The themes of the intrusive thoughts in people without OCD may be quite similar to those occurring in OCD. As such, some clinical scientists have suggested that these obsessions lie on a continuum that ranges from benign and transient to the uncontainable obsessive thoughts and resultant compulsions that characterize OCD. These observations suggest that it is not necessarily the nature of the obsessive thought that causes OCD, but rather how that thought is interpreted and acted upon by the patient.
Regrettably, OCD is usually a lifelong condition that waxes and wanes in intensity and frequency. However, treatment can help to diminish the frequency of the obsessions and make them more manageable.
What causes OCD?
As with numerous other diseases and disorders, there are multiple factors that contribute to the development of OCD. Genetic abnormalities appear to be important; DNA research has found a number of genes that may play roles in OCD (5, 6). Also, first-degree family members of OCD patients have an increased risk of OCD. Environmental factors (such as type of childhood, personal characteristics, socioeconomic status, and level of education) also have been statistically linked to OCD (5). A single causative factor has not been found in OCD. Rather, it is likely that the above factors and other biological determinants contribute to OCD behaviors, and also determine the types of symptoms, severity, response to treatments, and course of the illness. Details of these factors and their interplay can be discussed with your specialist if questions arise.
While genetic differences and environmental factors may explain some of the “why” about OCD, the “how” is very important to understand how it occurs. The “how” refers to the mechanisms and biological pathways through which OCD symptoms manifest. This is scientifically important, particularly in the development of better and more focused treatment strategies. The typical dysfunctional thoughts and actions in OCD appear to result from abnormalities of certain biological substances in the brain. These substances, derived from amino acids, are the means by which nerve cells communicate and coordinate their activities. They mediate all aspects of brain activities, including things like thought formation, memory, emotion, learning, physical movement, and virtually all other brain functions. These amino acid substances are collectively referred to as neurotransmitters (NT) (7, 8). Imbalances or disturbances of several of these NTs appear to be central in the development of OCD (9). The NTs that play important roles in OCD include glutamate, gamma-aminobutyric acid (GABA), serotonin (5-HT), dopamine, and to a lesser extent, norepinephrine. These NTs are the targets for many of the drugs that have been a cornerstone of OCD treatment.
As has been mentioned, there are quite a number of factors that, to varied extent, can result in OCD. Importantly, any of these causative factors can, themselves, also vary in the extent of its effect. For example, genetic abnormalities that result in the synthesis of a defective NT vary, such that the degree to which NT function is impaired may be minor, major, or have no effect at all. Further, the different nerve pathways that can affect OCD are also likely to impact on the types of symptoms that are experienced. In fact, although patients with OCD share some clinical characteristics, they frequently have symptoms that are distinctive (10).
Grouping patients according to their principal symptom profile is useful for scientific inquiry, clinical information exchange, specific treatment effectiveness, and when providing patients and their families with realistic long-term expectations. There are currently several principal symptom patterns that broadly characterize the majority of patients (11, 12). Nonetheless, overlapping of these traits also occur. A brief description of each follows.
Obsessive thoughts about contamination; washing and cleaning compulsions
Patients with this subtype have obsessive thoughts that they are contaminated, often from their environment. The symptoms described in the example above are typical for this subtype. The person with contamination obsessions can be fearful and very anxious, feelings only relieved by washing and/or decontamination compulsions. These rituals may consume many hours throughout the day.
Obsessive thoughts about doing harm; checking compulsions
This subtype is associated with great anxiety and distress from strong yet irrational anxiety that you failed to do something or made a mistake that could result in harm to yourself or others. Checking compulsions, in this group, are rituals undertaken repeatedly for reassurance or to relieve the fear and anxiety. Depending on the content of the obsessions, checking can take many forms such as constant worry that because you did not lock your door, intruders would not be prevented from entering and harming your family. Even if, rationally, you know you locked it, you are still compelled to return to the door to be sure, even though your behavior looks abnormal to others.
Obsessions about symmetry; compulsions of ordering, arranging, and counting
People in this group suffer from uncontrollable thoughts that if you fail to properly sort or balance objects something bad will happen. Examples include the strong need to have pencils all sharpened to exactly the same height, organizing clothing by color, or to be obsessive about arranging and rearranging the items on your desk in a precise and inflexible manner. Even finding a message or file that was out of place on your desk can cause distress.
Obsessive disturbing thoughts; mental compulsions
In this group, the obsessive thoughts usually have unacceptable (“taboo”), religious, sexual, violent, offensive, or impulsive/aggressive themes. Although these thoughts are not intentional or even characteristic of the affected individuals, they are usually horrifying or repugnant to the patients themselves. Examples are fears of being responsible for violent or sexual harm of loved ones. Importantly, the compulsions in this group manifest as mental rather than physical rituals, and as such may not be readily apparent to others unless revealed by the patient. Mental compulsions are frequently comprised of silent repeating of words or phrases, praying, trying to neutralize the obsessions with positive or safe thoughts, mental checking, and counting. Understandably, patients are often reticent to openly reveal the nature of the intrusive obsessive thoughts because of shame and the fear of being stigmatized by others. Likewise, the silent mental rituals may result in an incorrect diagnosis and suboptimal therapy.
The history of this category of OCD merits brief mention. Because mental compulsions were not overt, this subgroup was inaccurately thought to be a strictly obsessive disorder, and thus was often referred to as “isolated obsessive”, ruminators, or “pure O”.
Obsessions with excessive attachments to physical objects; hoarding compulsions
In this subgroup, individuals usually fear discarding things that might be useful to them someday, or have difficulty deciding whether to keep or discard items. They typically collect, often in tremendous excess, items such as old newspapers and magazines, bottles and containers, mail, and many more that usually are considered by others to have little to no value. The clutter may accumulate to the point that it can cause fires, unsanitary conditions, loss of a great deal of living space, and accident risks. Compared to other OCD subgroups, hoarders tend to have greater levels of anxiety and are comparatively difficult to treat (13).
A rather strong pattern of familial inheritance has been recognized; at least one-half of hoarders have first-degree family members who demonstrate hoarding-like behavior. Compared to other forms of OCD, depression and indecisiveness also tend to occur in family members. There also are several other important differences between hoarding and other OCD subgroups. In the latter, although the obsessions are typically uncontrollable and unwanted, patients are quite aware of the extent to which their behaviors are abnormal. Without this awareness, there would be little to no associated anxiety. By contrast, hoarders usually do not perceive their compulsions as problematic or dangerous. This lack of insight is an obstacle to effective cognitive-behavioral therapy (CBT). Research studies have also shown that the areas of the brain associated with the other subgroups are distinctly different to those in the hoarder form. Finally, clinical research studies of the effectiveness of conventional OCD drugs or CBT have shown mixed results, although recent data show superior outcomes when drug and cognitive-behavioral therapies are combined (13).
 A first-degree relative of a particular individual is his or her parents, siblings and children.
 Amino acids are the basic building blocks of all proteins and, therefore, an essential part of all biological structures and functions
- (UK). NCCfMH. Obsessive-Compulsive Disorder: Core Interventions in the Treatment of Obsessive-Compulsive Disorder and Body Dysmorphic Disorder. Obsessive-Compulsive Disorder: Core Interventions in the Treatment of Obsessive-Compulsive Disorder and Body Dysmorphic Disorder. 2006.
- Corcoran KM, Woody SR. Appraisals of obsessional thoughts in normal samples. Behav Res Ther. 2008;46(1):71-83.
- Rassin E, Muris P. Abnormal and normal obsessions: a reconsideration. Behav Res Ther. 2007;45(5):1065-70.
- Rassin E, Cougle JR, Muris P. Content difference between normal and abnormal obsessions. Behav Res Ther. 2007;45(11):2800-3.
- Grisham JR, Anderson TM, Sachdev PS. Genetic and environmental influences on obsessive-compulsive disorder. Eur Arch Psychiatry Clin Neurosci. 2008;258(2):107-16.
- Stewart SE, Mayerfeld C, Arnold PD, Crane JR, O’Dushlaine C, Fagerness JA, et al. Meta-analysis of association between obsessive-compulsive disorder and the 3′ region of neuronal glutamate transporter gene SLC1A1. Am J Med Genet B Neuropsychiatr Genet. 2013;162B(4):367-79.
- Campeau PM, Bernard G, Clayton PT. Neurotransmitter diseases and related conditions. Mol Genet Metab. 2007;92(3):189-97.
- Grados MA, Atkins EB, Kovacikova GI, McVicar E. A selective review of glutamate pharmacological therapy in obsessive-compulsive and related disorders. Psychol Res Behav Manag. 2015;8:115-31.
- Wu K, Hanna GL, Rosenberg DR, Arnold PD. The role of glutamate signaling in the pathogenesis and treatment of obsessive-compulsive disorder. Pharmacol Biochem Behav. 2012;100(4):726-35.
- Kingdom OU. The Different Types of Obsessive-Compulsive Disorder.
- Leckman JF, Bloch MH, King RA. Symptom dimensions and subtypes of obsessive-compulsive disorder: a developmental perspective. Dialogues Clin Neurosci. 2009;11(1):21-33.
- Starcevic V, Brakoulias V. Symptom subtypes of obsessive-compulsive disorder: are they relevant for treatment? Aust N Z J Psychiatry. 2008;42(8):651-61.
- Saxena S. Neurobiology and treatment of compulsive hoarding. CNS Spectr. 2008;13(9 Suppl 14):29-36.