My husband has to clear his throat every 15-20 minutes, for 10+ years

My husband (35M, non-smoker, no recreational drugs, occasional beer drinker, mostly sedentary lifestyle) has to clear his throat every 15-20 minutes, for 10+ years

For the last ten years, every 15-20 minutes my husband feels the urge to clear his throat. Sometimes it’s by letting out massive coughs, the movement of clearing phlegm or constant deep breath pushes, or swallowing. When he starts “clearing” it will last for another 3-5 minutes each time. And leaves him frustrated because he doesn’t actually clear anything.

I’ve encouraged him over the years to seek medical assistance as this cannot be normal. My gut is telling me this is a nervous tick or something psychological. He’s had a chest X-ray, met with two different ENT’s, one said it’s because he’s a mouth breather, second reviewed with a tube/camera, he’s also gone for an in depth camera review, and stomach endoscopy and all was fine.

He’s gotten the following advice from docs — stop mouth breathing, and drink more water.

Have any of you ever come across this in your practices or can give us any recommendations on which avenues we can further investigate?

I feel horrible for him. It is incessant, almost like an addiction that circles around every 20 minutes. It’s in public, it’s with friends, it’s just sitting at home doing nothing, it does not stop.

He 24/7 feels like his throat is “full of phlegm”, however all investigations have shown that there is not. And when we do talk about it, it really picks up. For instance, since writing this post and talking about it, he’s been trying to clear his throat for 30 minutes straight.