What is a common mental disorder?

What is a common mental disorder?

Shared psychosis is a rare mental illness in which a person without a primary mental illness begins to believe in the delusions of another person with psychosis or delusional disorder. For example, a wife may believe her husband’s delusions despite her good mental health.

In 1860, Baillarger first discovered a common mental disorder.Then it became known in many different terms. These include the following:

  • “Folie a deux” (crazy shared by two people) or “folie purgeé” created by Lasegue and Falret in 1877
  • “FolieCommuniqueé” (Communication Psychosis) created by Marandon de Montyel in 1881
  • “Folie simultaneé” (simultaneous psychosis; both parties are living in the primary delusion of mutual transmission) was created by Regis in 1880; also known as “folie induite”, created by Lehman Brothers in 1885

According to reports, the incidence of shared mental disorders is very low (accounting for 1.7% to 2.6% of hospitalizations).However, it is likely that many cases have not been reported.

Unless the person with the primary mental illness seeks help or acts in a noticeable manner, the secondary person is unlikely to seek help. This is because no one realizes that these delusions are untrue.

Common mental illness can also appear as a group phenomenon, in which case it is called the “rich second generation” or “many people’s madness”. The most obvious example is what happens in a cult, if the leader suffers from mental illness and transfers their delusions to the group. In a larger group environment, this may also be called collective hysteria.


The symptoms of a shared mental disorder will vary depending on the specific diagnosis of the main patient. However, some features of this disease are similar in different situations.

Secondary effect

Due to increased stress (such as increased cortisol levels), the health of people with delusions will be affected.

Due to long-term stress and fear, secondary mental health problems such as anxiety and depression may occur.

Due to the nature of mental illness, both people may not be in contact with reality and struggle in all aspects of daily life.

The main symptoms

Neither people with primary mental illness nor people with the same delusions have insight into the problem or realized that what they believe is not the truth.

Minor people usually develop delusions over time, thereby reducing their normal doubts or suspicions.

Depending on the nature of the main illness, the person may experience hallucinations (seeing or hearing things that do not exist) or delusions (believing in unreal things, even if there is evidence to show that fact).

Delusions may be bizarre, non-singular, emotionally consistent, or emotionally neutral (related to bipolar disorder). Strange delusions are things that are physically impossible. Most people agree that they will never happen, while non-weird delusions are possible but extremely unlikely.

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For example, a strange illusion might think that aliens are operating on you at night, while a non-strange illusion might think that the FBI is tracking your movements.

The delusion of emotional alignment matches your mood (depression or mania). For example, a person in a manic state may think that they are about to win a lot of money in a casino. In contrast, people who are in a state of depression may think that their relatives will be killed in an airplane accident.

Here are some other examples of possible delusions:

  • It is believed that radiation is transmitted from a foreign country to your home and causes stomach upset or diarrhea.
  • I believe you will get a lot of money soon.
  • Think that the FBI is tapping your phone or your family is being tracked.
  • Think that your neighbor has poisoned your food supply or water pipes in some way.

Generally speaking, both people will show paranoia, fear, and suspicion of others. If their delusions are challenged, they will also become defensive or angry. Those with delusions may seem euphoric.

The main characters in the relationship will not realize that they are making the other person sick. Instead, they think they are just showing them the truth because they have no insight into their mental illness.

As far as the second person is concerned, that person may show dependent personality traits in the form of fear and need for comfort. As far as their relatives diagnosed the disease, these people themselves are often susceptible to mental illness.

Common pairs include husband and wife (married or living together), mother and daughter, sisters or parents.


What caused the second person to accept the delusions of the mentally ill or delusional patient? There are several possible risk factors, including:

  • The social isolation of primary and secondary people from the outside world (when there is no social comparison, it is impossible to distinguish facts from delusions)
  • The occurrence of high levels of chronic stress or stressful life events
  • The dominant main character and the submissive secondary character (the secondary character may agree to keep the peace at first and begin to believe in delusions over time)
  • Close ties between primary and secondary people; usually long-term relationships with attachment (for example, family members, couples, sisters, etc.)
  • Minor people with neurotic, dependent or passive personality styles or people who are difficult to judge/critically think
  • Suffering from depression, schizophrenia or dementia and other mental illnesses secondary to
  • Untreated disease in the original individual (for example, delusion, schizophrenia, bipolar disorder)
  • The age difference between primary and secondary people
  • Dependence on primary and secondary personnel due to disability (for example, physical or mental)
  • The primary or secondary person is female (common mental disorders are more common in women)


How to diagnose common mental disorder? When it first appeared in the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), it was diagnosed as “sharing paranoia.”

Then, in DSM-IV, it was diagnosed as “shared psychosis”. Finally, in the recent DSM-5, it is no longer determined as a separate diagnosis; instead, it is diagnosed according to Section 298.9: Other Specific Schizophrenia Spectrum and Other Psychotic Disorders. The specific instructions are as follows:

“The delusional symptoms of the partner of a patient with delusional disorder: In a relationship, delusional material from the main partner provides the content of delusional beliefs for individuals who may not fully meet the criteria for delusional disorder.”

Finally, in the International Classification of Diseases (ICD-11), this disease is diagnosed as induced delusion.

In general, this disease is often undiagnosed or missed because usually no one knows about their mental illness. Normally, only when the main character takes action due to delusion, the case will be exposed, which will cause people to pay attention to the situation. For example, a person who is paranoid about his neighbor may attack.

However, even if the primary personnel come to receive treatment, the treatment provider may not know that secondary personnel are affected. Therefore, these types of cases may go undetected for a long time.

In order to diagnose the second person with this disease, their delusions are caused by contact with the first person, their delusions are similar in nature to the first person’s delusions, and their symptoms cannot be explained by some other problems, such as Medical condition or drug abuse.

Finally, the diagnostic steps include the following:

  • Clinical interviews and physical examinations; although there is no test to identify the disease, other problems can be ruled out through tests such as brain imaging, MRI scans, blood tests, and urine toxicology screening
  • Mental status check
  • Historical records from third parties (to ensure the accuracy of the report content)


Finally, how to treat common psychosis? Because this disease is often undiagnosed, usually only the main person can receive treatment for a mental disorder. However, once the secondary personnel are identified, a team approach that may be composed of various professionals such as doctors, nurses, pharmacists, and mental health professionals is required.

Because this disease is rare, there is no standard treatment plan. However, as the first measure, the separation of the secondary person from the primary person is typical. Usually, this seems to help reduce the second person’s delusions.

Specific treatments that may be provided include:

  • Psychotherapy to relieve emotional turbulence and reveal dysfunctional thinking patterns
  • Family therapy encourages healthy social relationships, promotes medication adherence, and helps minor people develop interests outside of relationships
  • Depending on each person’s symptoms, medications such as antipsychotics, tranquilizers, antidepressants, or mood stabilizers can also be used.


Unfortunately, due to the nature of common mental disorders, most people need professional help and cannot solve these problems on their own. However, if you are recovering from this disease, please keep the following in mind:

  • First, it is important to comply with any prescribed treatment plan.
  • Second, treatment usually involves meeting with the therapist, and the relationship you build and trust with that person is essential to getting better. Therefore, even if it feels difficult at first, it is important to continue to see the therapist.
  • Finally, if it is not treated in time, the disease will be chronic and will not get better. If you suspect that someone you know or you have a common mental disorder, please do your best to seek help.

Very good sentence

If you suspect that you or someone you know has a common mental disorder, it may be difficult to get out of this situation to decide what is truth and what is delusion. In this case, it is best to ask for help if you can, especially if you are a secondary person in the relationship and have difficulty relying on the main person.

If left untreated for a long time, the common mental disorder is unlikely to improve. Instead, it may lead to chronic stress and long-term effects on the physical and mental health of you and your loved ones.

If you are a major participant in a situation involving a common mental disorder and you are being treated by a professional, it is important to be frank about the impact of your illness on the people around you. Because this barrier is often missed or undiscovered, unless you share details of your situation and how others are involved, it is unlikely that secondary personnel will get help.

Most importantly, living in delusions is very scary and disturbing. However, the only way to improve the situation is to seek help, start to re-establish social connections outside the narrow relationship that has already developed, and receive treatment and/or medication as needed. Only by taking these steps will you be able to see an improvement in the situation.

In particular, if the secondary person is a child or dependant and cannot extend a helping hand by themselves, then other people must intervene and understand the situation in order to provide assistance.