Bail was set at $1 million.
According to a criminal complaint, Everson possessed explosive materials with the intent of making a destructive device and had a gun in his on-campus dormitory room.
According to campus police Chief Anne Glavin, Everson had been referred to see campus counselors by the school's residential life staff, who said it was apparent that Everson was clearly a danger to himself and others.
After a psychological assessment, he was taken to a mental health facility. Shortly thereafter, police discovered a shotgun and explosive materials in his dormitory.
Glavin said Everson had made indirect threats to students and faculty during his counseling sessions.
"The charges of possession of a firearm on a campus and possessing some ingredients that can blow up," said defense attorney Stanley Greenberg.
Along with a shotgun, there were bomb-making materials. Authorities would not specify what the ingredients were.
"I will simply say I am absolutely confident that something could have happened with what he had at his disposal," said CSUN Police Chief Anne Glavin.
Everson was a student last semester but was not enrolled for the spring semester.
Everson had been ordered into a campus counseling program after concerns about his well-being were voiced by his family.
According to police, he made indirect threats against students and staff while in counseling, leading to his arrest.
CSUN students were in shock after finding out about the arrest, and some say the arrest most likely averted a possible tragedy.
"It's kind of surprising and a little shocking. I feel that this is usually kind of a safe campus, but it sounds like they handled it though," said student Aaron Collins.
Staff at CSUN said the arrest and the tragedy in Tucson is a message that society needs to pay more attention to mental health issues.
"I think we need to pay attention when people are showing signs that there's difficulties, we need to say something," said LaShonna Goodman, executive director of the Family Focus Resource and Empowerment Center at CSUN.
Everson's arrest has some students on edge, saying they'll be more aware of their surroundings.
"There is always a possibility that something could happen. You just need to be on your toes and be aware of things," said student Leatrice Innocent.
Everson was scheduled to be arraigned Friday at the North Valley Superior Court.
Police are still investigating the incident.