(CNN) -- An Oregon teen accused of planning to bomb his high school suffers from a rare form of obsessive-compulsive disorder, his family said.
"My heart goes out to everyone affected by Grant's struggle with PANDAS, a rare form of OCD," Grant Acord's mother said through her attorney.
"I grieve for my son, but understand and support the efforts of law enforcement to keep our beloved community safe," the mother, Marianne Fox, added. "This is a challenging and confusing time for everyone who knows Grant. I will have no further comment while I wait with the rest of you to see what unfolds."
Acord, 17, is expected to appear in court for the first time Tuesday. He will be charged as an adult with attempted aggravated murder.
Acord's goal, said Benton County District Attorney John Haroldson, "was to model the Columbine shootings with some adjustments that would make it a greater success."
PANDAS, which stands for pediatric autoimmune neuropsychiatric disorder associated with streptococcus, is caused by the body's immune reaction to a strep infection, not the infection itself, according to the International OCD Foundation.
But there is no clear diagnostic criteria for PANDAS, according to the PANDAS Network.
Alan Lanker, the attorney for the mother, said Acord has received treatment, but said he did not know the details of the teen's treatment.
"He's very mentally ill. He has PANDAS. It's a brain infection that's causing a mental illness. It's been their concern for some time," Lanker said.
Police found six types of explosives after they arrested Acord on Thursday night at a home in Albany, Oregon, Haroldson said. Authorities believe he was planning to bomb West Albany High School.
They recovered napalm, pipe and drain cleaner bombs, as well as Molotov cocktails Friday from "a secret compartment that had been created in the floorboards" of the teen's bedroom, Haroldson said.
With the help of checklists and diagrams, the prosecutor said, Acord wanted to outdo the Columbine shootings.
The 1999 massacre at Colorado's Columbine High School left one teacher and 14 students dead, including the two gunmen.
Albany police became suspicious after they received information suggesting Acord was making a bomb with the intent of detonating it at a school.
"I've been doing this job for a while, and this was probably the scariest moment I've ever had as a school resource officer," Sgt. Alan Lynn told CNN affiliate KPTV.
"Luckily in this incident, somebody had the courage to come forward and say, 'This is what I know,' reported that to us, and we were able to investigate that. And because of that information, we were able to stop a horrific event (from) occurring in our community."
CNN's Jake Carpenter and AnneClaire Stapleton contributed to this report.