Speak of the Devil:
Darkness Brought to Light
“The greatest trick the Devil ever pulled was convincing the world he didn’t exist.”
— Charles Baudelaire (1821-1867), French poet
By Chris and the Editors
Updated 3/15/2024
In Scripture, Jesus Christ was famous throughout his ministry for two astounding feats: healing the physically sick and performing exorcisms on the demonically possessed. The Catholic Church teaches that demonic influences exist even today, and Christ granted his apostles the authority to cast them out, a power passed down through the priesthood. Today, about 250 priests across 30 countries practice the rite of exorcism. But how do we know that “demonic possession” is anything more than mental illness or hallucination?
To find out, I spoke with two well-known exorcists and a psychiatrist (and professor of psychiatry) who consults for exorcists, and also examined written witness testimony of recent exorcisms.
‘As a psychiatrist, I diagnose mental illness. Also, I help spot demonic possession.’
Dr. Richard Gallagher, a psychiatrist who has been requested by the Church to perform psychiatric screening evaluations on potential candidates for exorcisms, started out as a skeptic of exorcisms and ended up a believer. When I emailed him asking him about how one could convince others that demonic possessions are real, he responded,
Yes, skeptics can probably come up with rationalizations for everything — hysteria, mania, emergencies. But there are cases which are so unbelievable even those exaggerated claims would hardly hold.
You have to look at the overall context, of course, and often the sheer magnitude. It is the totality of the case that suggests a sound judgement of an answer.
His measured, evidence-based approach is apparent in an article he wrote for the Washington Post (“As a psychiatrist, I diagnose mental illness. Also, I help spot demonic possession.”) about his experience evaluating patients who might be possessed:
The same habits that shape what I do as a professor and psychiatrist — open-mindedness, respect for evidence and compassion for suffering people — led me to aid in the work of discerning attacks by what I believe are evil spirits and, just as critically, differentiating these extremely rare events from medical conditions.
Dr. Richard Gallagher is a practicing board-certified psychiatrist in Valhalla, New York and a professor of clinical psychiatry at New York Medical College (LinkedIn). He graduated from Princeton with an A.B. in Classics (phi beta kappa), earned his M.D. at SUNY Downstate, completed his residency in psychiatry at Yale, and lectured at Columbia in psychoanalysis.
His book Demonic Foes: My Twenty-Five Years as a Psychiatrist Investigating Possessions, Diabolic Attacks, and the Paranormal (originally published in 2019) documents his work helping “clergy from multiple denominations and faiths to filter episodes of mental illness — which represent the overwhelming majority of cases — from, literally, the devil’s work” (Gallagher #1). He told the first priest who requested his help that he “retained a deep skepticism of demonic possessions.” The priest replied, “This is why you’re the perfect man for the job” (Gallagher #2 28).
Demonic Foes starts with an endorsement by Dr. Joseph T. English, past president of the American Psychiatric Association (1992-1993) and Distinguished Professor of Psychiatry and Behavioral Sciences at New York Medical College:
As his past academic chairman for many years, I can attest that Dr. Richard Gallagher is a multitalented psychiatrist and a highly respected clinician who is also a valued teacher ... a superbly credentialed academic physician — a full professor of psychiatry — who can accurately offer personally informed accounts in painstaking detail of modern-day examples [of demonic possession] (Gallagher #2 ix).
Of Dr. Gallagher’s accounts of the various people he evaluated for the Church, the most dramatic is that of a woman he calls Julia in his book. Julia offered him permission to tell her story some day, saying, “It’s the least I can do, to maybe warn some other vulnerable people” (Gallagher #2 68).
He notes in the aforementioned Washington Post article,
In the late 1980s, I was introduced to a self-styled Satanic high priestess. She called herself a witch and dressed the part, with flowing dark clothes and black eye shadow around to her temples. In our many discussions, she acknowledged worshiping Satan as his ‘queen’ (Gallagher #1).
Julia had belonged to a satanic cult that performed various rituals including using her aborted fetuses at black masses (Gallagher #2 57).
Dr. Gallagher recounts his unusual interactions with Julia:
“But one night around 3 a.m., ... our two normally docile cats were going at it, smacking and clawing at each other, intent on inflicting some serious harm … ‘How’d you like those cats last night?’ she asked [the following day]” (Gallagher #2 43).
“She once told me how my own mother had died by the precise cause of ovarian cancer, which she had no way of knowing” (Gallagher #2 53).
“She calmly claimed that she could ‘see’ Father A. ‘in a blue windbreaker and khakis,’ walking along the seashore … She had never visited his home and knew nothing about where he lived … I immediately called Father A. on his cell phone and asked where he was and what he was wearing. ‘I’m usually in the rectory at this hour but decided to take a walk tonight … I’m saying my breviary along the shore in my khaki pants and a windbreaker’” (Gallagher #2 60).
Julia attended an exorcism attended by two exorcists, two nuns, and four laymen (including three strong men), and all eight witnesses attested to Dr. Gallagher that Julia levitated for half an hour:
Julia visibly rose about a foot off the chair and, in the clear impression of all attendees, would have ascended higher if it hadn’t been for several of those present, including all the men, laboring mightily to hold her down (Gallagher #2 63, 64).
While some of these details seem incredible, Gallagher makes it clear that what he saw with Julia is not an everyday occurrence. He notes that in his normal professional work as a psychiatrist, none of the ~25,000 cases he examined ever involved a possession (Gallagher #2 7). He is an experienced physician who diagnoses and treats patients with mental illnesses such as schizophrenia, bipolar disorder, delusional disorder, and dissociative identity disorder (previously known as “multiple personality disorder”). He is well aware that people may experience psychosis — a loss of contact with reality — and visual and auditory hallucinations. He notes,
Throughout my career, I have sometimes had to bluntly tell suffering patients and families, ‘No, the patient is ill, and there is no “demon of schizophrenia”’ (Gallagher #2 116).
The rarity of true demonic possessions, along with the long history of mental or physical illnesses confused with possessions in the past, does not detract from the fact that modern credible witnesses attest to signs of demonic possession that cannot be easily explained by science. Author Matt Baglio writes in his 2009 book The Rite: The Making of a Modern Exorcist:
Paranormal events — mind reading, levitation, speaking in previously unknown foreign languages — continue to elude scientific explanation. Perhaps one day science will be able to explain why these things happen. Until then, however, it would seem a betrayal of the tenets of scientific curiosity to discount a whole range of experiences affecting the lives of so many people simply because they defy such explanation (Baglio 207).
Dr. Richard Gallagher, Professor of Clinical Psychiatry at New York Medical College
Demonic possession is not mental illness
Exorcisms are rare and selective
Exorcists conduct exorcisms for only a minority of cases in which they’re consulted:
Fr. Grob estimates that about eighty-five percent of people who come to him do not need an exorcist … For Fr. Thomas, only ten percent of the people he saw had an issue of the diabolical (Fraune 42).
In the paper “Mastering the devil: A sociological analysis of the practice of a Catholic exorcist,” Giuseppe Giordan (University of Padova) and Adam Possamai (Western Sydney University) analyzed the 200-page notes of an Italian exorcist and discovered that only 55 cases out of 1075 initial consultations (5%) lead to a ritual of exorcism (Giordan & Possamai 2).
In the majority of cases, the person does not qualify for an exorcism because he or she does not display any definitive signs of possession, and psychiatric screening confirms psychological causes of erratic behavior.
Physical and psychiatric screening
Although people who consult exorcists do so because they have already seen multiple doctors without relief (Baglio 112), Catholic bishops often expect physical and psychiatric evaluations by qualified medical professionals before approving exorcisms, especially in the United States (Gallagher #2 8, Lampert 59). An exorcist typically has “a team of individuals (a psychiatrist, psychologist, and perhaps a neurologist) whom he trusts to help him with discernment” (Baglio 112). Msgr. Stephen Rossetti, the official exorcist for the Archdiocese of Washington, D.C., notes, “When someone is depressed, our first intervention is to suggest seeing a mental health professional and perhaps a psychiatrist to prescribe medication” (Rossetti 120).
Dr. Gallagher explains,
The role of the psychiatrist is to make sure that these phenomena don’t have a natural explanation before jumping to a preternatural or supernatural one. There are many individuals for one reason or another in life that become psychotic briefly; they are delusional, they may well hallucinate and they are prone to think that God, the Devil, a spirit, aliens, are communicating with them and they really believe it (Baglio 112).
He is careful to look for organic causes of symptoms. For example, he describes performing lab testing, an MRI, and an electroencephalogram (EEG) to rule out an underlying medical problem in a person reporting symptoms that could be interpreted as seizures or demonic attacks (Gallagher #2 125). All the medical testing was normal, and the patient’s symptoms improved after spiritual help.
Signs of a possession
Adam Blai is a layman (i.e. non-clergy) who has served as a demonology and exorcism expert in the Pittsburgh diocese (contact page). He has an M.S. in adult clinical psychology from Penn State and has assisted at dozens of exorcisms. He was interviewed about his experiences on CBS News: “Exorcism Expert A Former Skeptic, Now Trains Priests In Exorcisms.”
Blai states that the signs of possession include “understanding and speaking all languages, knowing secret details the person could not know by natural means, reacting against the holy (objects, persons, and so on), and strength beyond their physical condition” (Blai 10).
Testing for these possessions often involves blind tests to weed out fake possessions. For example, “exorcists will use regular water instead of holy water, or even read Latin prose out of a text instead of reciting a prayer to see whether the person responds” (Baglio 113).
Blai recounts his experiences working alongside exorcists in his book The Exorcism Files: True Stories of Demonic Possession (published in 2022):
“When several priests were present who spoke different languages, the woman was questioned in English, French, Latin, Lithuanian, and German. She grew up on a farm, had a high school education, and only spoke English. Regardless, she either spoke or correctly answered all the questions. She also could correctly tell if something was blessed just by looking at it. The sign of unusual strength was shown in the actual exorcisms, where it sometimes took five healthy men to keep her restrained, and even then, she never tired over multiple hours” (Blai 55).
“Luis responded correctly to questions in Latin, Hebrew, and German. He may have had some previous knowledge of Latin, but he later confirmed that he knew neither Hebrew nor German. At the beginning of the next session, we held a box of relics near him, and he could tell us the genders, descriptions, and in some cases, names of the saints they came from” (Blai 67).
Blai notes details that have parallels with the case described by Dr. Gallagher. Julia also had access to hidden knowledge and showed unusual strength that required multiple strong people to hold her down.
Exorcism defined
Most people who think they are possessed are not; many of them need medical help. However, in the rare cases when a person exhibits signs of demonic possession that can’t be explained by mental or physical illness, spiritual help is more appropriate.
There are two types of exorcisms: minor and major. Minor exorcisms are simple prayers requesting God for freedom from sin, such as those performed at baptisms. A major exorcism is the full-blown rite that people usually think of when they hear the word “exorcism,” directed toward the “expulsion of demons or to the liberation from demonic possession” as defined by the Catechism of the Catholic Church (Sophia Institute Press 37). A “possession” involves the complete demonic takeover of a person’s body and consciousness (Sophia Institute Press 27). Major exorcisms consist of deliverance prayers and the use of sacramentals, which are blessed objects such as salt, oil, and water.
We’ll talk later about the circumstances leading up to an exorcism, as well as the aftermath. For now, let’s dive straight into more testimonies about exorcisms, many of which bear similarities.
By the way, in case you suspect that these witnesses are liars or lunatics (to borrow words from C.S. Lewis), you can always talk to these people before reaching a conclusion. I cold-emailed several of them, leading to dozens of back-and-forth messages, and received kind and helpful responses. I’ve included links to their contact info, as well as a list of all my sources (at the bottom of this page) for your own perusal.
Adam Blai, demonology expert for the Diocese of Pittsburgh
Testimonies by Exorcists
Monsignor Stephen Rossetti, Ph.D. (1951-), Washington, D.C., USA (Wikipedia)
Msgr. Stephen Rossetti has served as the exorcist for the Archdiocese of Washington, D.C., for the past 15 years. He has also been the chaplain of the Washington Nationals for the past 10 years, as described in the Washington Post: “‘Bless these bats’: Meet the Nationals’ priest praying for a World Series victory.”
He is also a licensed psychologist, with a Ph.D. in counseling psychology from Boston College, and a research associate professor at the Catholic University of America (profile/contact page).
He graduated from the US Air Force Academy in 1973 and served as a second lieutenant in the US Air Force, where he worked for six years.
Msgr. Rossetti recounts his learnings and experiences running an exorcism team in his book Diary of an American Exorcist: Demons, Possession, and the Modern-Day Battle against Ancient Evil (originally published in 2021):
“One day, I had in hand a small, 1½-inch-diameter theca, or container, with a relic of St. Peter in it. I laid the theca on the temple of the afflicted person, and the body visibly jerked. I commanded him to tell us which saint it was (keeping the theca’s identity hidden), and he said ‘Peter’” (Rossetti #1 192).
“In one session, a man began to manifest and the entire eyeballs of his blue eyes turned completely black” (Rossetti #2).
Fr. Gabriele Amorth (1925-2016), Rome, Italy (Wikipedia)
Fr. Amorth was a prominent exorcist for the Diocese of Rome who founded the International Association of Exorcists. He received the War Cross for Military Valor for his involvement in the Italian resistance movement during World War II, serving as commander of the 3rd Battalion of the 2nd Italian Brigade. He also served as a deputy for Giulio Andreotti, who later became Italian prime minister, helping him draft the country’s new constitution (Sophia Institute Press 8).
Fr. Amorth was a highly prolific author of works on demonology and exorcisms (five of them are referenced in this article), and his long history as an exorcist includes many noteworthy events as follows.
From An Exorcist Explains the Demonic: The Antics of Satan and His Army of Fallen Angels (2016):
“... a young mechanic … even before the exorcism was initiated, began to levitate just as I placed my hand on his shoulder. Five people could not hold him still” (Amorth #1 100).
“He exorcized a young peasant girl of seventeen, who was more accustomed to speaking in her dialect than in Italian ... he said to them in Greek rather than in Italian, ‘Shut up! Stop that!’ Immediately the girl turned toward him and asked him, in a satanic manner: ‘Why do you order me to be quiet? Tell it to these two who continue to interrupt you!’” (Amorth #1 100).
From Father Amorth: My Battle against Satan (2018):
“Just as I entered the front door, all the chairs around the table fell to the floor, and from the ceiling pieces of paper with strange names written on them began to fall. During the benediction, the person began to vomit some pins, which surely had not come from her stomach; rather they materialized in a dense saliva as it came out of her mouth” (Amorth #4 76).
“During an exorcism, the beast said to me, ‘If you do not leave me alone in this woman, I shall touch something that is most dear to you.’ I knew immediately that he was speaking of my mother. That same day, Momma fell from the stairs and broke her thigh bone, but I did not know it immediately. The next day, while I was exorcizing the same woman, the Devil said to me, ‘Now are you content with what I did?’” (Amorth #4 89).
From The Devil Is Afraid of Me: The Life and Work of the World's Most Popular Exorcist (2020):
“... the demon resumed his shrieks, making the possessed turn his head back and his eyes roll; and he remained like this with his back arched for a quarter of an hour … All of a sudden, the room became extremely cold and iced crystals formed on the windows and the walls … the young man’s body stiffened so much that he became hard and at a certain point began to levitate; and for several minutes, he remained hovering three feet in the air” (Amorth #5 44).
Fr. Vincent Lampert (1963-), Indiana, USA (Wikipedia)
Fr. Vince Lampert has been an exorcist for the Diocese of Indianapolis since 2000. As part of this training, he assisted in 40 exorcisms led by Fr. Carmine de Filippis, a mentor for exorcists in Rome (Lampert #2). Fr. Vince mentioned a particularly memorable possession in one of those exorcisms with Fr. Carmine, in his 2020 book Exorcism: The Battle against Satan and His Demons and in an interview with Matt Baglio:
“Immediately their eyes rolled in the back of their head, they began foaming at the mouth, and uttered blasphemies against God and the exorcist … and began to levitate” (Lampert #1 27).
“A woman in her early forties … had shaken so violently that Father Vince had seen her levitate five inches off the chair, at which point Father Carmine had simply pushed her back down with the palm of his hand” (Baglio 163).
Fr. José Antonio Fortea (1968-), Madrid, Spain (Wikipedia)
Fr. Fortea, a priest and novelist, served as an exorcist for the Diocese of Alcalá de Henares in Spain and narrated his life experiences, including exorcisms, in his 2008 Spanish memoir Memorias de un Exorcista:
“During the prayers for the poor and unfortunate boy, what surprised us all the most was his improvised version of the Christmas carol Adeste Fideles, with blasphemous lyrics. Apart from the physical strength he developed, which was astonishing. Five men had to put in a lot of effort to hold him down. And that was while the boy was lying on his back, on a mat. And those who held him tried to restrain him by putting all their weight on him. But the strength he displayed for three hours was incredible … He revealed many hidden sins of all those present … But as soon as the holy water fell on him, it seemed to scorch him and he only screamed in agony. At another moment he shouted, ‘I saw your Son of God buried! He did not rise!’” (Fortea 219-220).
“But a few details betrayed the presence of the Demon. A certain order I gave in complicated Latin had been understood and obeyed instantly. That, along with the aversion to the crucifix, holy water, and relics, betrayed the Demon, no matter how much it tried to appear as if it was the woman's madness” (Fortea 296).
Fr. Candido Amantini (1914-1992), Rome, Italy (Wikipedia)
Fr. Candido Amantini was an exorcist for the Diocese of Rome for 36 years and Fr. Gabriele Amorth’s mentor (Stanze Vaticane). Fr. Amorth documented many exorcisms which he conducted jointly with Fr. Candido, as detailed in An Exorcist Tells His Story:
“Father Candido was exorcizing a possessed individual. The sacristan approached him with the aspergillum [an implement for sprinkling holy water] and the bucket of holy water. Immediately the demon turned to him and said, ‘With that water you can wash your snout!’ Only then the sacristan remembered that he had filled the bucket at the faucet but had forgotten to have it blessed” (Amorth #3 122).
“One day Father Candido invited a priest who prided himself on his skepticism to be present during an exorcism … At one point, the demon turned to him, saying, ‘You say that you do not believe I exist. But you believe in women; yes, you believe in women, and how!’ That poor unfortunate priest, quietly and walking backward, reached the door and quickly disappeared” (Amorth #3 94).
“After working on her without any result all evening and half the night, the exorcists decided to quit. The next morning, Father Candido was exorcizing a small boy, six or seven years old. The devil, from within that boy, began to mock the priest: ‘Last night you worked hard, but you did not gain anything. We won! And I was there too!’” (Amorth #3 74).
Monsignor Stephen Rossetti, exorcist for the Archdiosese of Washington, D.C.
Fr. José Antonio Fortea
Cost of an exorcism: $0
Many of these possessions demonstrate similar paranormal features: hidden knowledge, including foreign languages that the person does not know, unusual strength, and levitation. The afflicted people often react against holy objects but not unblessed ones. Understandably, many people are skeptical of stories of the paranormal, but one striking feature of these testimonies is the credibility of these witnesses. They are well-regarded leaders whose profession emphasizes the importance of trustworthiness and integrity. Exorcisms are usually performed within a team, including a female helper or assistants to help restrain the afflicted person if needed (Baglio 78), and medical professionals are generally consulted as well. These witnesses corroborate one another’s testimony.
Of course, one of the most common motives in any fraudulent scheme is money. Dr. Gallagher describes people with mercenary motives who may call themselves “psychic healers,” “parapsychologists,” or “demonologists” despite their lack of training or experience so that they can charge large fees to suffering people. Even some ministers or televangelists may ask for a large payment or “donation.” He warns:
As a physician, I generally consult upon these cases pro bono, and I am not, of course, directly offering spiritual assistance or spiritual advice. I recommend to victims of demonic assault that they find someone truly committed and spiritually advanced to help them out, and I advise that they be extremely leery of anyone who charges them money. Pastoral help should be a vocation, not a business (Gallagher #2 196).
Fr. Gary Thomas, the priest who is the main focus of Baglio’s book The Rite, explained to me over email in February 2024:
There is no extra compensation for priests involved in the ministry of exorcism. I receive my normal salary as any diocesan priest would but nothing more. In fact, there is an unwritten rule that exorcists do not take any money personally for the ministry they provide nor do any members of their respective team.
There have been times when people have offered me money for what we were able to do to liberate them and I always first say that ‘no money or fee is necessary nor required.’ If they continue, then I can direct them to provide an account that our diocese manages that is used for people who cannot afford the psychological testing and interviews that are required, workshops that I would like to attend specific to this ministry or sending my team on workshops for the same purpose but never take any money for myself. That is an unwritten rule but made very clear in Rome at the school at the Regina Apostolorum and also the school in Chicago.
Protocols for patient privacy
The Church has strict privacy regulations on exorcisms akin to what is expected for medical patients in the healthcare industry.
When I asked Fr. Gary whether I would be able to ever observe an exorcism, he replied:
Since you are not part of a deliverance/exorcism team, I cannot imagine a circumstance in which a priest exorcist or a team can allow you to witness these proceedings for several reasons:
1) Privacy of the person who is the subject of the deliverance/exorcism.
2) Liability that could expose the diocese, parish and even the individual members of the team and priest or deacon
3) Every person must be fingerprinted by the diocese in order to work with people who are vulnerable adults or minors
…
Even speaking with victims of possession who have been liberated is not always easy.
I have had a number of media outlets who have contacted me over the years who were inquiring about interviewing some of the people whom I ministered. There again are privacy issues. It is a very embarrassing experience for someone to disclose both the ways that the demonic become attached and the process of becoming liberated even though it is highly evangelizing because of the freedom that the person experiences as well as for the family who often have suffered along with the person.
The major emphasis on privacy also explains the lack of visible public video or photographic evidence for exorcisms, as Fr. Gary explains:
The forward to the Rite of Exorcism specifically prohibits any recordings, audio or visual, and any kinds of media from being used in the performance of solemn rites or deliverances by a priest exorcist or members of his team.
Causes of demonic afflictions
Paragraphs 2116 and 2117 of the Catechism of the Catholic Church notes:
All forms of divination are to be rejected: recourse to Satan or demons, conjuring up the dead or other practices falsely supposed to ‘unveil’ the future. Consulting horoscopes, astrology, palm reading, interpretation of omens and lots, the phenomena of clairvoyance, and recourse to mediums all conceal a desire for power over time, history, and, in the last analysis, other human beings, as well as a wish to conciliate hidden powers. They contradict the honor, respect, and loving fear that we owe to God alone.
All practices of magic or sorcery, by which one attempts to tame occult powers, so as to place them at one’s service and have a supernatural power over others — even if this were for the sake of restoring their health — are gravely contrary to the virtue of religion. These practices are even more to be condemned when accompanied by the intention of harming someone, or when they have recourse to the intervention of demons. Wearing charms is also reprehensible. Spiritism often implies divination or magical practices; the Church for her part warns the faithful against it. Recourse to so-called traditional cures does not justify either the invocation of evil powers or the exploitation of another’s credulity.
Exorcists universally claim that these occult practices are responsible for demonic influences. The exorcism cases listed by Fr. Amorth, Blai, Dr. Gallagher, and others typically involve people who belonged to Satanic sects, practiced divination, engaged in witchcraft or other pagan rituals, etc.
The study by Giordan and Possamai showed that in 19.1% of the exorcism consultation cases that they analyzed the participants openly admitted “involvement with occult arts, alternative spiritualities, Satanic sects and rituals, folk/alternative healing practices, and also Masonry” (Giordan and Possamai 11).
The remedy: faith and forgiveness
Exorcists also point to the lack of a faith life as a contributing factor to inviting demonic influence. In contrast to the dramatic nature of some exorcisms, exorcists regularly prescribe a seemingly boring (but challenging) remedy for a permanent recovery from demonic afflictions and for preventing them in the first place: living a good Christian life. For people who already practice other faiths, Fr. Amorth tells them to pray and fulfill their existing spiritual, professional, and moral duties (Baglio 192). He says that “spiritual help, such as serious prayer and the confession of one’s sins, are often more valuable than exorcisms” (Gallagher #2 196).
Exorcists regularly state that sincere repentance and confessions are stronger than exorcisms and can make exorcisms entirely unnecessary, especially in the milder cases (Amorth #3 86, Baglio 62). Father Giancarlo Gramolazzo, past president of the International Association of Exorcists, once said that “90 percent of what helps possessed individuals occurs outside the exorcism rituals” (Gallagher #2 196).
Furthermore, in the cases where the demonic disturbances involve tensions with other individuals, sincere forgiveness is cited as an important medicine for liberation (Amorth #2 80, Palilla 1581).
Conversions are the strongest evidence
When I emailed Msgr. Rossetti, he pointed out to me that “the strongest evidence [for the authenticity of exorcisms] is the stories and experiences of those who went through it and converted.” Indeed, books such as Rescued from Satan: 14 People Recount Their Journey from Demonic Possession to Liberation (published in 2018) are filled with testimony from people who underwent exorcisms, were liberated, and became faithful Christian believers as a result.
In addition, Dr. Gallagher and Adam Blai started out skeptical themselves and became believers after their extensive experience working with people with signs of demonic possession, as well as seeing the healing power of exorcism with their own eyes.
My personal favorite story is that of Matt Baglio, the author of The Rite: The Making of a Modern Exorcist. A non-practicing “cultural Catholic” who had attended Mass only a few times a year (Baglio 244), he set out to write a book chronicling the training and formation of future exorcist Fr. Gary Thomas. In the process, he interviewed many exorcists in Rome, spoke with the victims of demonic possessions, and observed several exorcisms firsthand. By the end of this journey, he became a believer. (And the book is very good too!)
Sources
Amorth, Gabriele. An Exorcist Explains the Demonic: The Antics of Satan and His Army of Fallen Angels. Sophia Institute Press, 20 Oct. 2016.
Amorth, Gabriele. An Exorcist: More Stories. Ignatius Press, 15 Sept. 2015.
Amorth, Gabriele. An Exorcist Tells His Story. Ignatius Press, 21 July 2015.
Amorth, Gabriele. Father Amorth: My Battle against Satan. Sophia Institute Press, 2 Oct. 2018.
Amorth, Gabriele. The Devil Is Afraid of Me: The Life and Work of the World's Most Popular Exorcist. Sophia Institute Press, 26 Feb. 2020.
Blai, Adam. The Exorcism Files: True Stories of Demonic Possession. Sophia Institute Press, 27 Sept. 2022.
Baglio, Matt. The Rite: The Making of a Modern Exorcist. Doubleday, 5 Mar. 2009.
Fortea, José Antonio. Memorias de Un Exorcista. Planeta Publishing, 1 Feb. 2009.
Fraune, Charles. Slaying Dragons: What Exorcists See & What We Should Know. The Retreat Box Press, 28 Sept. 2019.
Gallagher, Richard. “As a Psychiatrist, I Diagnose Mental Illness. Also, I Help Spot Demonic Possession.” Washington Post, 1 July 2016, www.washingtonpost.com/posteverything/wp/2016/07/01/as-a-psychiatrist-i-diagnose-mental-illness-and-sometimes-demonic-possession.
Gallagher, Richard. Demonic Foes: My Twenty-Five Years as a Psychiatrist Investigating Possessions, Diabolic Attacks, and the Paranormal. Harper One, 6 Oct. 2020.
Giordan, Giuseppe & Possamai, Adam. (2017). Mastering the devil: A sociological analysis of the practice of a Catholic exorcist. Current Sociology. 66. 001139211668681. 10.1177/0011392116686817.
Krieger Spivak, Diane. “Exorcist priest knows how to fight evil.” Joliet Herald News, 27 Jan. 2011.
Lampert, Vincent. Exorcism: The Battle against Satan and His Demons. Emmaus Road Publishing, 24 Sept. 2020.
Lampert, Vincent. “The Truth about Exorcism.” Catholic Answers, 5 Oct. 2020, www.catholic.com/audio/caf/the-truth-about-exorcism.
Palilla, Benigno. Rescued from Satan: 14 People Recount their Journey from Demonic Possession to Liberation. Padre Pio Press, 13 Sept. 2018.
Rossetti, Stephen. Diary of an American Exorcist: Demons, Possession, and the Modern-Day Battle against Ancient Evil. Sophia Institute Press, 17 May 2021.
Rossetti, Stephen. “Exorcist Diary #123: A Week in Hell.” St. Michael Center, 30 Jan. 2021, www.catholicexorcism.org/post/exorcist-diary-119-a-week-in-hell.
Sophia Institute Press. The Pope’s Exorcist: 101 Questions about Fr. Gabriele Amorth. Sophia Institute Press, 23 Mar. 2023.
Stanze Vaticane. “Rome’s Chief Exorcist Reveals the Secrets of Hell.” Aleteia, 9 Aug. 2014, aleteia.org/2014/08/09/romes-chief-exorcist-reveals-the-secrets-of-hell.