My tics are like that friend who crashes on your couch. He eats all your food, he breaks your favorite guitar and he embarrasses you in front of every girl you meet. You wake up 11 years later, and he’s still there. – Trevor Smith

Eighteen-year-old Trevor Smith is ruled by thousands of tics, constant movements that batter his body and disrupt his day.

They dictate if he can walk in a straight line or make it smoothly up a flight of stairs. They can take him left when he wanted to go right. It’s his arms, his legs, his head. It’s sitting. It’s standing. It’s all of it — everything.

After 11 years, his joints have taken a lot of abuse. The friend on the couch has more than worn out his welcome.

Trevor has Tourette Syndrome, a neurodevelopmental disorder that packs its punch with sudden, uncontrollable movements and sounds, known as tics. One in every 100 children between 5 and 17 in the U.S. has a tic disorder, but an alarming half go undiagnosed, according to the Centers For Disease Control and Prevention.

Trevor’s case is severe and in his case medications don’t work, behavioral therapy doesn’t work, and time hasn’t made it better, like doctors early on thought it would. He has little control over the tics and how they abuse his body. As Trevor puts it, “It’s up to the whims of the day.”

Trevor and his family live in Greene, Iowa, two hours northeast of Des Moines — “kind of in the middle of a cornfield.” He pauses, full of humor and wisdom that belie his 18 years: “No, exactly in the middle of a cornfield.”

It’s the humor that some don’t get to witness if they can’t get past the constant motions. The tics began barging into Trevor’s life when he was 7, starting with subtle eye twitches and ballooning from there. As the family moved frequently with his dad’s jobs, the tics tagged along.

When Trevor was 7, a doctor diagnosed him with a generalized Tic Disorder, predicting he’d grow out of it by the end of his teens. At 8, the diagnosis was official Tourette Syndrome. At 9 and 10, new arm and leg tics made that seem doubtful. At 14, his symptoms rapidly worsened and he began an uncontrollable humming noise and a cough. At that point the tics had officially unpacked their bags to stay.

By then, his mom had mostly been homeschooling Trevor and his younger sisters. It was a relief from bullying and the classmates who taunted that you’d catch “a disease” if you touched him.

Soon enough, Trevor found that loud rock music quieted the jerking movements and made him forget about the tics. Picking up his guitar and playing Metallica has been the only treatment that truly helps. Folks around him comment on the transformation. He’d play 24/7 if he could.

Trevor has tried half a dozen medications. The last one, they thought, was a miracle. But the effects didn’t last. A few months after he started taking it, the tics started pushing through the medication, so his doctor kept upping the dose to square off against them. Then Trevor reached a point where he couldn’t safely take another increase.

One of the side effects was weight gain. He put on 100 pounds (which he later lost). He felt defeated.

But new — and promising — hope came February 4. That friend who crashes on the couch might finally get the boot, thanks to an experimental surgery called Deep Brain Stimulation or DBS.

The procedure had been part of the discussion for a few years now, but it was out of Trevor’s reach. Because it’s not FDA-approved for Tourette Syndrome, the costly procedure was denied by three insurance companies. Along with personal fundraising efforts and scrambling to save enough money on their own, it was a battle that consumed the family. In December, an appeal to approve the surgery, with Mayo covering nearly 90 percent, was granted by the Mayo Clinic’s charitable foundation.

“Everyone in my family called it a Christmas miracle,” Trevor said.

Trevor and his family are cautiously optimistic about the DBS surgery, where electrodes were implanted to regulate his brain’s abnormal impulses. While the procedure comes with significant risks, the family has been told they can expect a dramatic reduction in tics. The early indicators look good, according to his dad.

If the good news keeps coming, Trevor may find preparing for an engineering degree in his community college classes easier, and have more time for his beloved music. He knows his tics don’t make him who he is. All along, he’s been way more than the constant, cruel movements that his body endures. He thinks it’s time the rest of the world knows too.