Mental health professionals in Israel are on the lookout for a rare mental disease which usually has outbreaks during auspicious times or event. With the upcoming Jewish holidays and related Biblical prophecies, blood-moon, end of the Shmittah cycle and the beginning of the Jubilee, and finally the vote on the Iran nuclear deal, which many believe will lead to Armageddon, cases of Jerusalem Syndrome are expected to pop up across the country.

Jerusalem Syndrome, a very real phenomenon named after the capital city of Israel, is a type of mental illness defined by religiously themed obsessive ideas, delusions or other psychosis-like experiences that are triggered by a visit to the city of Jerusalem. Psychologists expect many cases of this psychosis to crop up in and around the Holy City in the near future, if they haven’t begun to appear already.

Though this malady is typified by religious ecstasy or zealousness, it is not limited to any one religion. Jerusalem Syndrome does seem to be limited to one city, albeit an intensely unique one. It was first clinically identified by Dr. Yair Bar El, formerly director of the Kfar Shaul Psychiatric Hospital.

On an average, 100 cases of Jerusalem Syndrome are reported each year in Jerusalem clinics and hospitals, of which approximately 40 require hospitalization. This may not sound like the makings of an epidemic, however it should be considered that this mental illness only appears in one city in the world.

According to mental health counselors, Jerusalem Syndrome usually takes one of three forms. The first category is comprised of individuals who have a previous history of mental illness and travel to Jerusalem because they see themselves as having a personal calling or role in the messianic process. Often, these people will strongly identify with a Biblical character, perhaps even taking it on as their own identity. The second category is people who may be idiosyncratic and their relationship with religion and Jerusalem is more of an obsession or compulsion.

The final category, and the most prevalent, is people who have no history of mental illness, are previously mentally balanced and fully-functional, but develop a psychotic episode as a result of contact with the city of Jerusalem. They usually arrive in Israel as tourists with no special purpose, accompanied by family or as part of a group. The resulting, unexpected episode is of an intensely religious nature, and typically full recovery occurs a few weeks after leaving the city, regardless of treatment. Most cases are isolated incidents, with no psychotic episodes occurring again in the person’s life.

There are symptoms by which an episode of Jerusalem Syndrome can be anticipated. A psychotic break is usually preceded by anxiety or nervousness, obsessive cleanliness and the need to constantly shout Biblical verses or Psalms. Tour guides are aware of the possibility of Jerusalem Syndrome and are on alert for tourists who suddenly want to leave the group and go off on their own. The most extreme manifestation of Jerusalem Syndrome is when a person puts on robes and goes to a holy site in Jerusalem to give a sermon, usually to tell humanity to repent or prepare for the End of Days.

Treatment usually involves medicating and sedating the person to immediately remove them from the Jerusalem vicinity. After several weeks in treatment with a mental health professional, sufferers of Jerusalem Syndrome typically recover to their pre-psychosis break.

There are many theories as to what causes Jerusalem Syndrome. Professor Eliezer Witztum, a psychiatrist at Jerusalem’s Herzog Memorial Hospital, explains that “many Christians view Jerusalem as the site of the Armageddon and the second coming. When they visit Jerusalem, they may experience cognitive dissonance because of the conflict between their mental image of ancient Jerusalem and the reality of the modern city. Religious Jews with the syndrome may believe that the building of the third temple is imminent, that the ancient animal sacrifices will be restored, and that their own Messiah will soon arrive.”

It may sound unfair, as if the city itself, a modern bustling metropolis, is being blamed for driving people insane. Unfortunately, there may be some basis to that. Jerusalem is unique in its spiritual and religious nature. It is the focus of much religious thought and the setting where religions clash.  Jerusalem physically looks different, and the Old City is still very similar to how it appeared in Biblical times. Great events have occurred in the ancient city and even more are expected to occur in the future. It is the focus of religious pilgrimage and the religious fervor is palpable. In many ways, Jerusalem is emotionally overwhelming and exceeds expectations. Simply walking the streets awakens sensitivities that could have lain dormant in any other setting.

However, Jerusalem Syndrome can have drastic consequences. In 1969, Michael Rohan, a non-Jewish tourist from Australia, set fire to the Al Aqsa Mosque, triggering massive Muslim riots. At his trial, Rohan told the court that he believed himself to be “the Lord’s emissary” in accordance with a prophecy in the Book of Zechariah. As a result of the incident, non-Muslims were banned from the Temple Mount for three years. This was not an isolated incident, as there have been similar incidents by Jews and non-Jews.

Jerusalem Syndrome has even become a part of pop culture, being featured in various novels, episodes of the X-Files, Dig, and even Homer Simpson developed Jerusalem Syndrome when he came to visit the city with his religious Christian Neighbor, Ed Flanders.