Do you feel uncomfortable when you see such a title?

Author: Zhang Ge, Zhan Yafeng, Wang Zheng (Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences)

The article comes from the Science Academy official account (ID: kexuedayuan)

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Let’s look at two sets of pictures first:

Picture 1

Photo 2

Some people commented that Picture 1 “cured my obsessive-compulsive disorder”. On the contrary, more people commented that Picture 2 “made my obsessive-compulsive disorder flare up”. In real life, most people can’t help but correct the “disharmonious” or “irregular” phenomena like those in Picture 2. Is this the legendary “obsessive-compulsive disorder”?

In fact, most people who do not have professional medical knowledge have a distorted understanding of OCD, and the misused term "OCD" has exacerbated the misunderstanding of OCD among ordinary people. Just like the similar scenes in the two sets of pictures above, most people think that Picture 1 is comfortable, while Picture 2 is uncomfortable. This is because everyone has a preference for neatness and regularity, and this innate tendency to follow rules and correctness cannot be rashly labeled as "OCD".

So, what is "obsessive-compulsive disorder"?

Obsessive-compulsive disorder is a disease, so don't just talk about it.

The protagonist of the movie "The Aviator" washes his hands so hard that they bleed

In the movie "The Aviator", the protagonist played by Oscar-winning actor Leonardo Dicaprio, Howard Hughes, a famous American aeronautical engineer, is a patient suffering from obsessive-compulsive disorder. He is afraid of touching potentially unclean objects or bacteria, so he washes his hands repeatedly to reduce his fear and anxiety about uncleanliness. Tortured, he tries his best to get rid of or eliminate these ideas that invade his brain, but any control and suppression is in vain. This is a typical manifestation of obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is closely related to anxiety disorders. Its main clinical manifestations are persistent, intrusive obsessive thoughts or repetitive, purposeful compulsive behaviors that strictly follow a series of rules due to uncertainty about things. People with OCD worry too much about danger, hygiene, or injury, and thus continue to consciously focus on threats, which is the obsessive thoughts. In order to cope with the pain and/or anxiety caused by these obsessive thoughts, patients will take a series of actions to temporarily relieve the pain and/or anxiety, which is the compulsive behavior.

The biggest characteristic of patients with obsessive-compulsive disorder is that they realize that these compulsive symptoms are meaningless and completely contrary to their own wishes, and they will resist them in their minds. This strong conflict makes patients fall into strong self-blame and anxiety, which brings great pain and seriously affects their normal work and life.

Theoretical basis of obsessive-compulsive disorder

Why do people suffer from obsessive-compulsive disorder?

Obsessive-compulsive disorder is a neurosis with a very complex etiology, and its pathogenesis has not yet been clearly understood. Over the years, many researchers have tried to explore the etiology of obsessive-compulsive disorder from a variety of perspectives, including genetics, neuroscience, and psychology.

Early knowledge of OCD came from patients with specific neurological damage. After the influenza epidemic in the first half of the 20th century, OCD symptoms were found in patients with encephalitis lethargica and basal ganglia lesions. Subsequent studies have shown that OCD may also be caused by neurological damage in other brain areas (such as the frontal lobe), suggesting that the prefrontal-striatal circuit may play a role in the pathogenesis of OCD.

In recent years, thanks to the rapid development of magnetic resonance neuroimaging technology, humans have been able to observe brain neural activity non-invasively, and this technological advancement has greatly promoted people's understanding of brain function. Current psychological research based on neuroimaging and cognitive-emotional studies has shown that the cortico-striatal-thalamic-cortical (CSTC) circuit damage model related to sensorimotor, cognitive, emotional and motivational processes has become a generally accepted neuropathological model of obsessive-compulsive disorder in obsessive-compulsive disorder neurology and pathology.

The CSTC circuit contains direct and indirect pathways. In a healthy state, the excitatory direct pathway is inhibited by the indirect pathway. In patients with obsessive-compulsive disorder, the inhibition threshold is lowered, causing the direct pathway to be activated, which leads to excessive activation of the orbitofrontal cortex-subcutaneous nucleus pathway, causing patients to pay excessive attention to stimuli such as danger, hygiene, or injury. Patients temporarily relieve the anxiety and pain caused by threats through compulsive behaviors, but this short-term relief will lead to the reinforcement of behavior, which will aggravate repetitive and compulsive behaviors when obsessive thoughts recur.

Neural circuits associated with obsessive-compulsive disorder

Do you have obsessive compulsive disorder?

Let’s look at Figure 2 at the beginning of this article. Most people will experience similar discomfort, but not everyone who feels uncomfortable has obsessive-compulsive disorder.

I believe you have also encountered similar situations, while tidying up the desk or cleaning the room, you asked yourself "Do I have obsessive-compulsive disorder?" However, these behaviors mainly occur because everyone has a preference for beautiful things. Although there are some people who are too perfectionist, they can at most be called obsessive-compulsive, not obsessive-compulsive.

(Photo source: veer photo library)

Obsessive-compulsive disorder is a serious mental illness. Only when obsessive thoughts or compulsive behaviors cause severe pain or interfere with an individual's social and role functions, and last for at least one hour a day, can it be diagnosed as "obsessive-compulsive disorder". At present, the clinical diagnosis of obsessive-compulsive disorder is mainly based on the Diagnostic and Statistical Manual Fifth Edition (DSM-V) of the American Psychiatric Association, and the Y-BOCS (Yale-Brown Obsessive Compulsive Scale) is widely used to rate the severity of obsessive-compulsive disorder.

In clinical practice, it is not easy to accurately diagnose obsessive-compulsive disorder. There are two main difficulties in clinical diagnosis of obsessive-compulsive disorder, namely, the clinical manifestations of obsessive-compulsive disorder are highly heterogeneous and comorbid. On the one hand, the specific manifestations of obsessive-compulsive thoughts and compulsive behaviors are diverse, and patients with obsessive-compulsive disorder show different symptom dimensions and courses. Obsessive-compulsive disorder can be divided into different subtypes, and the various subtypes have different etiological origins, so they are often called obsessive-compulsive spectrum disorders. The famous psychiatrist Freud was the first to discover that obsessive-compulsive disorder is heterogeneous. Subsequent studies have found that not all patients with obsessive-compulsive disorder respond to medications or specific psychotherapy, which further supports the heterogeneous characteristics of obsessive-compulsive disorder.

On the other hand, 90% of OCD patients suffer from at least one other mental disorder that meets the DSM criteria, with anxiety and affective disorders being the most common. In addition, taking anxiety and depression as examples, their treatment methods overlap with those of OCD. It is these complex comorbidities that have brought certain difficulties to the accurate diagnosis and treatment of OCD.

How to solve the diagnostic problem of obsessive-compulsive disorder?

The development of technology has brought hope for solving the diagnostic problem of obsessive-compulsive disorder. Currently, we mainly rely on massive data and non-human primate models to understand and diagnose obsessive-compulsive disorder.

Massive data is an important factor in promoting our understanding of the heterogeneity of obsessive-compulsive disorder. In addition to having rich features, these data also have breadth (i.e., large sample size) and depth (i.e., multimodal data collected on the same individual, such as genetic, imaging, behavioral, etc. data). These features increase the reliability, repeatability, and generalization of research results and help evaluate the utility of different models.

In addition, since primate model animals are species that are relatively close to humans in brain function and structure, non-human primate models can also be used to study human brain diseases. The advantages are: first, the disease models developed by non-human primates are highly similar to human diseases; second, the pathogenic mechanism of non-human primate models is relatively simple, which greatly simplifies the disease model and excludes and controls factors unrelated to the disease as much as possible; finally, brain function connection map data (including brain function imaging data such as magnetic resonance imaging) that are comparable and transferable to humans can be obtained. For example, macaque disease models help understand the mechanisms of human brain diseases, promote the transformation of basic research into clinical applications, and provide valuable clues for objective diagnosis.

Why should ordinary people know about obsessive-compulsive disorder?

Obsessive-compulsive disorder usually develops during adolescence, and the course of the disease spans the most important learning, social, marriage and love periods in the patient's life, which greatly affects the patient's quality of life. In addition, obsessive-compulsive disorder patients often suffer from great mental torture while being ashamed to seek medical treatment for fear of secular comments. Usually, the disease has lasted for a long time when first diagnosed, which greatly increases the difficulty and cost of treatment.

(Photo source: veer photo library)

People once thought that the incidence of obsessive-compulsive disorder was not high, but with the continuous deepening of research in recent years, researchers have found that the incidence of obsessive-compulsive disorder is much higher than expected. In 2019, a national epidemiological survey on mental illness led by Professor Huang Yueqin of Peking University found that the lifetime incidence of obsessive-compulsive disorder in Chinese people is 2.4%, which is basically the same as the lifetime incidence of 2.3% in Americans. Nearly 1 billion people in the world have experienced compulsive behavior.

On the one hand, we hope to help ordinary people who are not in this field understand OCD, correctly understand OCD, and not be misled by the popular concept of "OCD". At the same time, we hope to detect and treat real OCD early. Especially for adolescent OCD patients, they are in an important period of physical and mental development, and early diagnosis and treatment of OCD are even more important. On the other hand, a comprehensive review of the key and difficult issues in the field of obsessive-compulsive spectrum disorder research will help inspire clinicians and researchers to deeply analyze the brain pathological mechanisms behind the symptoms, improve and innovate related diagnosis and treatment technologies, and thus promote the development of the frontier in the field.

References:

[1] Stein et al.. 2019, Obsessive-compulsive disorder. Nat Rev Dis Primers.

[2] Obsessive-compulsive disorder professional committee of the psychiatric branch of the Chinese Medical Doctor Association, 2019, Standards for the construction of obsessive-compulsive disorder diagnosis and treatment centers in China. Chinese Journal of Psychiatry.

[3] Schilder, 1938, The organic background of obsessions and compulsions. Am J Psychiatry.

[4] Khanna, 1988, Obsessive-compulsive disorder: is there a frontal lobe dysfunction? Biol Psychiatry.

[5] Pauls et al., 2014, Obsessive-compulsive disorder: an integrative genetic and neurobiological perspective. Nat Rev Neurosci.

[6] Leckman et al., 2010, Obsessive-compulsive disorder: a review of the diagnostic criteria and possible subtypes and dimensional specifiers for DSM-V. Depress Anxiety.

[7] Goodman et al., 1989, The Yale-Brown obsessive-compulsive scale. I. Development, use, and reliability. Arch Gen Psychiatry.

[8] Robbins et al., 2019, Obsessive-compulsive disorder: puzzles and prospects. Neuron.

[9] Moritz et al., 2011, Was Freud partly right on obsessive-compulsive disorder (OCD)? Investigation of latent aggression in OCD. Psychiatry Res.

[10] Feczko et al., 2020, Methods and challenges for assessing heterogeneity. Biol Psychiatry.

[11] Jennings et al., 2016, Opportunities and challenges in modeling human brain disorders in transgenic primates. Nat Neurosci.

[12] Huang et al., 2019, Prevalence of mental disorders in China: a cross-sectional epidemiological study. Lancet Psychiatry.

[13] Fullana et al., 2009, Obsessions and compulsions in the community: prevalence, interference, help-seeking, development stability, and co-occurring psychiatric conditions. Am J Psychiatry.