(CNN) Spencer Smith was an outgoing 16-year-old high school sophomore who loved teasing his sisters, spending time with friends and -- most of all -- football.
If he wasn't out on the field, he was on the couch watching his beloved New England Patriots on TV, his father, Jay, told CNN.
"Every time football season ended, he was on a high, win or lose," he said.
Like so many children, Spencer was frustrated when schools closed amid the coronavirus pandemic last spring, his father said. To get him through, he immersed himself in football, looking toward the fall season when he expected to be a lineman for his high school team in Brunswick, Maine.
"He focused on building up his muscles," Smith said, adding his son went on a special diet and bought all the equipment he could, in addition to riding his bike and jogging.
"He got an old tire ... tied a rope around it and cut up a backpack. All the neighbors would see him out there dragging it around the lawn. He raked the lawn almost all summer long with that tire. It was full of grass."
But when the pandemic dragged on and the school first announced a scaled-back football season and then a switch to flag football, Smith said Spencer began to worry. He was a tackler, not a runner, after all.
Ultimately, he left the team. He stopped working out and began to take more naps. Previously an honor roll student, Spencer also struggled with remote learning.
Looking back, Spencer's dad say there were signs how much he was missing his teammates and the barbecues and Thursday night spaghetti suppers.
But nothing could have prepared him for that December morning.
Jay Smith got a text from his wife saying Spencer must have overslept again, as he had missed homeroom. He went to his son's bedroom. He was dead by suicide.
"I just asked, 'Spencer, why?'" his father said.
A growing number of families are like the Smiths -- losing a child to suicide during the pandemic.
Youth suicides had generally been rising before the pandemic and it is too early to link an increase in deaths directly to school closures, said Katrina Rufino, an associate professor of psychology at the University of Houston.
But she co-authored a study that found there had been a significant increase in the number of ER visits to a Houston children's hospital related to mental health since coronavirus hit the US.
In Houston, the rise in teenagers having suicidal thoughts and harming themselves coincided with shutdowns linked to the pandemic, including school closures, Rufino and colleagues wrote in the paper published in Pediatrics, the journal of the American Academy of Pediatrics.
"Our analysis found that there were significantly higher rates of suicide ideation in March and July 2020 -- that is when you really saw the effects here in Houston," said Rufino about the study, which examined ER admittance to Texas Children's Hospital for youth aged 11 to 21.
"March was when things were first hitting, things started shutting down. Here in Houston, we had the rodeo closed, schools went home after Spring Break. And then July is when we really started to see our surge here in Houston."
In north Texas, 37 students were admitted to a Fort Worth hospital following suicide attempts in September -- the highest monthly total since tracking began in 2015, CNN affiliate KTVT reported.
These statistics mirror trends experts are monitoring on a national level. According to the CDC, the proportion of emergency room visits related to mental health concerns doubled between April and October for children between the ages of 5 and 11, and tripled for those between the ages of 12 and 17, compared to the same period in 2019.
There are concerns across the nation about students' mental health. In Nevada, Clark County school district, the fifth largest in the country, which includes Las Vegas, has been particularly hard hit.
Nineteen student suicides have been reported in the last nine months, more than double the number reported for the whole of 2019.
The youngest child to die was just nine years old.
Superintendent Jesus Jara says he feels the losses personally.
"It's heartbreaking as a superintendent when you lose a child. It's heartbreaking as a leader," he said.
Jara said some children are struggling with not enough to eat. For some, their parents have perhaps lost jobs or the children are having to take on new responsibilities with schools out.
Signs of trouble began in early fall when a warning system on school-issued laptops and tablets, programmed to detect mental and emotional struggles, showed an increase in alarming searches.
"Kids are googling 'how to suicide.' You get the alerts -- you get four or five a day," Jara said.
He said he understood the fear of teachers returning to classrooms as cases continued to soar in Nevada, but added he knew he had to get his 350,000 students back to in-person learning.
The Clark County school board has now backed a plan to resume in-person teaching for elementary students from March, which is welcome news to Jara.
"My teachers are working really hard, but it's that face-to-face interaction. You can't take for granted a loud lunchroom," he said.
In-person schools can also help to stop more students feeling overwhelmed after the loss of a classmate -- a process Rufino from the University of Houston calls "postvention" and which she says is critically important in conjunction with prevention measures.
"In a youth suicide, you really need to worry about things like suicide contagion or suicide clusters, because they are rather common in youth," she told CNN. "When a youth suicide takes place, a school is going to rapidly implement a 'postvention' plan. It provides students and teachers with much needed support," she said, adding they could deal with the tragic loss together.
"However, if schools aren't on campus, it's going to be really difficult to implement any sort of a postvention plan. And it's possible that it's going to leave parents floundering, unsure of how to talk to their kids."
President Joe Biden has committed to reopening schools in 100 days, investing in Covid testing and getting needed funds to districts. Recent data has also shown that schools can reopen safely if proper mitigation strategies are implemented.
Spencer Smith's parents believe that if schools and youth programs had been open with proper social distancing, allowing children to be together safely, he might not have died.
They urge other families not to take face-to-face interaction for granted.
"Check on them every morning, every night, no matter how old they are, if they're at home," Jay Smith said. "Always give them a hug, tell them how proud you are of them. I remember always telling Spencer that. I think I should have told him more."