SHIZUOKA (Kyodo) -- Japanese actor Ryoko Hirosue was released from custody on Wednesday, her office said on her official website, after being arrested on suspicion of assaulting a nurse at a central Japan hospital following a traffic accident.

No alcohol or illicit drugs were detected in her system after tests by police in Shizuoka Prefecture, the office said, adding she has shown signs of emotional instability and will undergo treatment.

The actor, who sustained minor injuries in the expressway collision on April 7, was brought to the hospital in Shimada, Shizuoka. There, she allegedly kicked a female nurse multiple times and scratched her arm after the nurse sought to prevent her from wandering around the hospital.

Hirosue rear-ended a truck on the Shin-Tomei Expressway while driving with a male passenger who suffered a fracture. The truck driver was uninjured.

According to a statement posted earlier on her website, the incident with the nurse occurred after the accident "left her in a panic."

Hirosue, who rose to fame in the 1990s, appeared in a string of TV dramas such as "Beach Boys" and starred in films including the Oscar-winning "Departures."