The patient, a boy in middle school, had witnessed a relative choke to the point of unconsciousness in a restaurant seven months before.

His parents had brought him for a psychological evaluation because he had been miserable ever since.

His eating had suffered, too – it was as though he had been the one for whom the paramedics had been called that day.

"It got worse and worse until I had to chew everything until it was liquid and I took the smallest bites ever," he said. He rapidly lost more than 10 pounds.  He then restricted his eating to mostly smooth liquid foods such yogurt and pudding and calorie supplement drinks.  He had gained back most of the weight but lost not an ounce of the misery.

Although he had once been an easygoing, social boy who "loved to eat," he also began avoiding restaurants, the crowded lunch table at school, and the relative who had choked (and was fine, by the way). His parents said their son was easily upset by the sight of peers talking with their mouths full or the sound of coughing.

They had taken him to a therapist six months before, but it hadn't been helpful: "It was about 5 minutes of talking and the rest playing."

This boy had experienced a traumatic event and had severely restricted his diet and many of his activities.  Was the more appropriate diagnosis post-traumatic stress disorder or specific phobia of choking?

SOLUTION:

To a large extent, the boy's diagnosis didn't matter. The effective, scientifically based psychological treatment for both PTSD and specific phobia is called exposure, a form of behavioral therapy. Patients are encouraged in therapy sessions to gradually approach what they would rather avoid on the rationale that avoiding a safe situation causes greater fear of that situation, which in turn drives greater avoidance.

Hence, in exposure therapy, patients are encouraged and praised for every step they take toward sticking with what scares them until it doesn't scare them anymore.  In the case of PTSD, that's typically the memory of the trauma, because even though the traumatic event itself was dangerous, a memory of it – no matter how unpleasant – is safe.

In the case of choking phobia, the gradual exposure is to food, specifically swallowing it.

In the case of this patient, avoiding swallowing was far more dangerous than avoiding a memory.  We proceeded with a provisional diagnosis of choking phobia and focused our therapy efforts on having him eat increasingly chewy foods, without over-chewing them. Sessions were not about playing, they were about swallowing.

It worked. Once this brave boy had made enough progress with good bites and quick swallows in my office, we began holding sessions in restaurants. He graduated to French fries, then hoagies, then pizza, then steak.  His eating and weight went back to normal. He could discuss the memory of his relative choking without tears. He returned to his happy, carefree self – and his lunch table.

Katherine Dahlsgaard is lead psychologist of the Anxiety Behaviors Clinic at Children's Hospital of Philadelphia.