Back in high school, I had a friend who was depressed. His teacher, who had seen us together in the halls frequently, pulled me aside one day to express her concerns because he had developed a bad attitude and started sleeping in class, and his grades were plummeting.

This teacher has stayed on my mind throughout the years because she took the time to investigate a student's behavior she found troubling instead of just disciplining him repeatedly. By reaching out to his friends, she was able to identify that he had in fact been struggling with depression and then took the steps to get him help.

Unfortunately, depression in high school is becoming more common these days. According to a new report by the U.S. Substance Abuse and Mental Health Services Administration, 2.7 million teenagers in America suffered from depression between 2013 and 2014. Compared with previous data from the year before, the overall rate jumped from 9.9 percent to 11 percent.

In May 2014, the World Health Organization also released a report revealing depression to be the No. 1 cause of illness and disability for 10- to 19-year-olds, with suicide being one of the top three causes of adolescent deaths worldwide. After being on the decline in the U.S. from 1986 through 1999, overall suicide rates have jumped 24 percent from 1999 through 2014 according to a study by The National Center for Health Statistics.

With these staggering increases in both depression and suicide, this brings up one important question: What is behind the rise in teen depression?

Rosemary Rubin, co-chair of the LA County Child and Adolescent Review Committee and former board member and founding member of California Association of School Counselors, thinks a combination of factors play into it.

"Social media may be a part of it," she said. "Certainly when we think of the role social media plays in bullying and the inability to escape from it, for some young people that can lead to depression and possible feelings of suicide."

With social media becoming more and more prevalent, it's a factor not to be taken lightly. Statistically speaking, 92 percent of teenagers go online daily with 71 percent reporting that they use more than one social networking platform.

"When we see or hear about young people who spend more time on their phones or electronic devices rather than communicating face-to-face, that can add to the feeling of disconnection and isolation, which can lead to depression," Rubin added.

Aside from the overuse of technology and social media, the following are general reasons she's encountered for why teenagers struggle with depression:

• High or unrealistic expectations, such as the desire to get good grades, be accepted by everyone or land a great-paying job
• Bullying or cyberbullying
• Biological family history of depression or mental illness
• Abuse in any form — substance, physical, emotional or sexual
• Personal trauma or disruptive circumstances, such as parental divorce or the death of a family member
• Lack of support from family and/or friends
• Unbalanced lifestyle, such as insufficient exercise, sleep or free time

Manpreet K. Singh, director of the Pediatric Mood Disorders Clinic and an assistant professor of psychiatry and behavioral sciences at Lucile Packard Children's Hospital at Stanford, told Deseret News National that depression rates for adolescents are increasing, and it could be because "we're recognizing it more."

Another possibility is that more teens may be willing to admit to their depression as our society slowly removes the stigmas associated with mental illness. During National Mental Health Awareness Month in April, President Barack Obama issued a proclamation, part of which stated:

"This month, we renew our commitment to ridding our society of the stigma associated with mental illness, encourage those living with mental health conditions to get the help they need and reaffirm our pledge to ensure those who need help have access to the support, acceptance and resources they deserve."

While the solution is not black and white, one thing is certain: Teen depression needs to be addressed. So how should teachers approach this issue if they believe a student in their class could be going through it?

Rubin believes it's important for teachers to be knowledgeable about depression. She emphasized that recognizing the signs of depression and getting help for the student are crucial. By referring him or her to the school counselor or school nurse, they will be able to follow up with the student's parents and get the additional help that's needed.

"It's also important for [teachers] to be aware that depression can be masked," Rubin said. "In other words, it does not always appear as we think of it. Sometimes 'acting out' can be a form of depression."

The online publication, "Interventions That Work" by the Association for Supervision and Curriculum Development, states that students dealing with depression typically "give up more quickly on tasks they perceive as daunting, refuse to attempt academic work they find too difficult and quickly doubt their ability to independently complete academic tasks or solve problems."

Like my friend from high school, teens with depression may withdraw and refuse to participate in class, or the opposite, becoming more defiant and troublesome instead. Any noticeable changes are worth taking into account.

To find out about the additional symptoms of teen depression, there is an online guide by HelpGuide.org with more information. For those who are concerned that a teen may be contemplating suicide the signs are listed on TeenSuicide.us.

Because students spend a lot of time at school, teachers play a key role when it comes to identifying depression. Sometimes all it takes is a teacher reaching out to the teen or in my case, the teen's friends.