When Jacob was just 3 years old, his mom noticed that he was acting a little differently than his siblings had at that age.

He had started to develop certain habits and tendencies that were somewhat disconcerting to his family. By the time he turned 5, his pediatrician had diagnosed him with autism.

But after that, his behavioral issues only got worse.

All photos via Dignity Health.

Not only was he falling behind academically, he started acting out uncontrollably in class. One time, he had such a bad tantrum that the students had to be evacuated from the classroom while members of the faculty subdued him.

His teacher saw enormous potential in Jacob, but she was unable to get through to him.

"He's a brilliant kid, he has great ideas," she says, "Putting that on paper is really hard."

His mother, Erika, felt similarly.

"I know he felt alone, and he didn't know how to express himself well enough to have us even understand how it was impacting him, but we could see it in his face," Erika explains.

She felt at the end of her rope. She knew she had to do something new to help him since what they were currently doing didn't seem to be working.

So Erika decided to take him to see a new pediatrician — Dignity Health's Dr. Andrew Katz.

And he made a surprising suggestion — maybe Jacob's autism diagnosis was wrong?

"Erika's main concern was does my child have autism, but it wasn't really my leading thought," Katz says.

Katz with Jacob and his mom.

While this second opinion was certainly momentous, it's not all that strange given this country's pre-occupation with autism.

Studies have shown that ever since researchers started tracking autism rates in the United States in 2000, the number of cases has risen dramatically, almost in tandem with the growing awareness. This suggests that it's more likely to come up as a possible diagnosis simply because it's on parents' and doctors' radars.

Thankfully, however, Katz is very discerning. He listened intently to what both Erika and Jacob had to say and came to a totally different conclusion than what they'd heard in the past.

Katz told Erika he thought her son actually had a severe case of attention deficit hyperactive disorder (ADHD).

He also said that Jacob's behavioral issues would likely resolve once he was on the right medication.

Sure enough, within just a few days of being properly medicated, Jacob's behavior totally turned around. He began talking more articulately and focusing on tasks. His experience at school changed; he was more social, he was able to deal with disappointments in much more constructive ways, and his academic performance improved significantly.

The switch was truly amazing for everyone who cared about him to behold.

"For a while with the diagnosis of autism, we were wondering if Jacob would ever be able to live on his own or get a job," Erika remarks. "And now, he's capable of taking care of himself, and I really don't question that anymore."

Of course, not all diagnoses are misdiagnoses, but sometimes it's worth getting a second opinion, especially when you're dealing with unfamiliar territory.

For Jacob's family, the move was life-changing. Anyone who's met him can see that.

"He's compassionate, he's intelligent, he's thoughtful, he's organized, which is amazing for someone with the diagnosis he has," Jacob's teacher says. "In the future, I think Jacob can do whatever he wants. I think he'll be just fine."

Check out the whole story behind Jacob's diagnosis here: