Mohammod Youssuf Abdulazeez, who killed five service members in Tennessee on Thursday, was reportedly suffering depression and fighting drug and alcohol abuse since his early teen years, a family spokesman said, according to the Associated Press (AP). He added that these personal issues were the root cause of the shooting at Chattanooga military sites, in which the 24-year-old was also shot dead by police gunfire.

The spokesman said, according to the AP, that last year the Kuwait-born Jordanian spent several months in Jordan under a mutual agreement with his parents to try and quit alcohol and drugs, and disconnect with some friends who relatives believed were bad influence. At the age of about 13 years, he was treated by a child psychiatrist for depression, said the family representative, who spoke on condition of anonymity.

"They (Abdulazeez’s relatives) do not know of anything else to explain it," the spokesman said, according to the AP, adding: "He was medicated like many children are. Through high school and college he did a better job sometimes than others staying with it."

Relatives also reportedly tried to admit him to an in-patient program for drug and alcohol abuse several years ago, but were not successful because a health insurer refused to approve the expenses. Abdulazeez had owned guns for years and called himself an “Arab redneck” or “Muslim redneck,” and shot at squirrels when he was a child, the representative added.

Several recent incidents fit the pattern described by the spokesman. In May 2013, Abdulazeez lost his job at a nuclear power plant in Ohio due to a failed drug test, federal officials reportedly said. Prior to the shooting, he had started working night shift at a manufacturing plant and was taking medicines because he had trouble sleeping during the day, the representative said, according to the AP. Abdulazeez  also had a prescription for muscle relaxants for his back problem.

After returning from Jordan, Abdulazeez was arrested in April for driving under influence in the pre-dawn hours. According to a police report, he was with friends who had been smoking marijuana and also had white powder on his nose. He reportedly told the police officer that he had sniffed powdered caffeine.

"In our culture, if a son or daughter is having those sorts of problems, they keep it a secret because of the shame," Bassam Issa, president of the Islamic Society of Greater Chattanooga, told the AP, adding: "As a parent, you always want to be able to say your child is making you proud, not that they are struggling." Issa said that despite knowing Abdulazeez’s father well, he knew nothing of the drug problems.

Abdul Ofoli, who teaches electrical engineering at the University of Tennessee, where Abdulazeez graduated in 2012, said that he met his former student in the mosque six days before the shooting, and saw “the same friendly guy as before.”

FBI Special Agent Ed Reinhold reportedly said that the agents were currently looking into all aspects of Abdulazeez’s life, and had not yet found a connection to Islamic terror groups. Also, it remains unclear why he targeted military facilities, which killed four Marines and injured a sailor, who died Saturday.