Last year, a news column circulated the web, announcing the American Psychological Association had decided to classify strong religious beliefs as mental illness. According to the article, a five-year study by the APA concluded that devout belief in a deity could hinder “one’s ability to make conscientious decisions about common sense matters.” Refusals by Jehovah’s Witnesses to accept life-saving treatments, such as blood transfusions, were given as an example.

Of course, this turned out to be a fake news story. But it still drew legitimate media coverage and outrage from readers. Fact-checking websites like Snopes had to point out the column was satirical.

To many, this was a ridiculous stunt. But for me, a physician specializing in mental health, the satire hits home in many ways. My colleagues and I often care for patients suffering from hallucinations, prophesying, and claiming to speak with God, among other symptoms—in mental health care, it’s sometimes very difficult to tell apart religious belief from mental illness.

Part of this is because the classification of mental illness often relies on subjective criteria. We can’t diagnose many mental health conditions with brain scans or blood tests. Our conclusions frequently stem from the behaviors we see before us.

Take an example of a man who walks into an emergency department, mumbling incoherently. He says he’s hearing voices in his head, but insists there’s nothing wrong with him. He hasn’t used any drugs or alcohol. If he were to be evaluated by mental health professionals, there’s a good chance he might be diagnosed with a psychotic disorder like schizophrenia.

But what if that same man were deeply religious? What if his incomprehensible language was speaking in tongues? If he could hear Jesus speaking to him? He might also insist nothing were wrong with him. After all, he’s practicing his faith.

It’s not just the ambiguities of mental health diagnoses that create this problem—the vague nature of how we define religion further complicates matters. For example, the Church of Scientology argued with the Internal Revenue Service for years to be classified as a charitable religious organization and to qualify for tax-exempt status. The Church eventually won this battle in 1993, a major step towards becoming a mainstream American religion.

According to Going Clear: Scientology, Hollywood, and the Prison of Belief, a book by Pulitzer Prize-winning author Lawrence Wright, Scientologists believe in alien spirits inhabiting human bodies. Many believe they have special powers, like telekinesis and telepathy.

This puts mental health professionals in a tricky, cultural bind. Before 1993, should mental health professionals have treated patients expressing these beliefs as psychotic? After 1993, as faithful adherents?

These distinctions carry profound medical and legal implications. In his book Under the Banner of Heaven: A Story of Violent Faith, journalist Jon Krakauer chronicled the case of Utah v. Lafferty, which addressed the 1984 killings of a woman and a child by two Mormon fundamentalists, Ron and Dan Lafferty. Over the last several decades, the question of Ron Lafferty’s mental health has played a key role in the case, as both sides have battled over his competency to stand trial.

The defense has argued that Ron is mentally ill and therefore should not be put to death. In interviews, Ron has claimed to be a prophet, endorsed hearing the voice of Christ, and expressed fears about “an evil homosexual spirit trying to invade his body through his anus.” Psychiatric experts have testified that Ron appeared to suffer from a psychotic illness, such as schizoaffective disorder.

The prosecution has sought to uphold his competency to stand trial, relating his bizarre ideas to religious practices worldwide. In the words of Dr. Noel Gardner, a psychiatrist who testified for the prosecution, “the majority of people in our country believe in God. Most people in our country say they pray to God. It’s a common experience. And while the labels that Mr. Lafferty uses are certainly unusual, the thought forms themselves are really very common…to all of us.”

A local news column from 2013 summed up the complexities of this ongoing case—“Where is the line between faith and delusion? Between malice and mental illness?”

These are tough questions. The practices of Scientology and Mormon fundamentalism are far from the only examples of this oft-blurred line between religion and mental health care. Virtually every religion has unusual beliefs and rituals, from consuming the flesh and blood of Christ in Catholicism to fasting as a way of atoning for sins in Judaism.

Some have gone so far as to argue religion may actually be a form of mental illness. In 2006, biologist Richard Dawkins published his book The God Delusion, in which he characterizes belief in God as delusional. Dawkins cites the definition of a delusion as “a persistent false belief held in the face of strong contradictory evidence, especially as a symptom of a psychiatric disorder.”

Dawkins’ book has been wildly controversial, prompting academic rebuttals, hate mail, and even threats to jail his publishers. Still, as of 2014, The God Delusion has sold over 3 million copies worldwide.

As a mental health provider, I don’t believe it’s my job to cast judgment on patients’ religious beliefs. It’s my job to use medical evidence to evaluate and treat mental illness so as to alleviate suffering among my patients. Today, we have some objective medical tests to diagnose mental illness, as in neurosyphilis or B12 deficiency. But we need more to help guide us through the difficult circumstances in which mental health care and religion collide.

In time though, perhaps we will. I have faith.