SALEM, N.H. — An 18-year-old man attacked his mother after she threatened to withhold a prescription drug he was taking, then eluded capture as local schools went briefly into lockdown, police in Salem said.

Police, who initially said they were investigating an attempted homicide, said George stabbed 49-year-old Catherine George in the neck, leg and hand and hit her in the head with a hammer. She was airlifted to a Boston hospital. Her condition wasn’t immediately known.

After the 8 a.m. assault, George fled in one car before ditching it in Derry and stealing another, police said. He was taken into custody when he returned to the scene of the attack, according to Salem Deputy Police Chief Shawn Patten.

In court later Thursday, prosecutors said his mother was worried he was taking too much Adderall, a drug often prescribed to treat attention deficit disorder. He became angry and attacked his mother when she said she would keep the drug from him.

Salem High School and Pinkerton Academy in Derry were put in precautionary lockdown as police sought George. Chip Underhill, a spokesman for Pinkerton, said George had been a student there for three years and withdrew at the end of last year.

George was charged with two felony counts of first-degree assault with a deadly weapon and ordered held on $250,000 bail. He’s scheduled to return to court on Oct. 31.

Catherine George surrendered her nursing license in June after admitting she killed her 55-year-old brother-in-law, Randall Percival, in October 2012 by giving him 300 units of insulin. She told police that Percival was terminally ill and didn’t want to suffer anymore. George pleaded guilty to unlawfully possessing the drug.