Authorities in Texas say that nearly 120 reported drug overdoses in Austin and Dallas in a five-day period might be linked to the same Dallas supplier.

The overdoses involve K2, a synthetic drug that is supposed to mimic the effects of marijuana. It is also marketed under other names, like Spice and Black Mamba.

"Several [patients] came in with similar symptoms of psychosis, altered mental status, abnormal behavior -- ranged from very sedated to an agitated state," Dr. James d’Etienne of Baylor Medical Center told WFAA. “We don't know what they are putting into these synthetic drugs."

Patients ranged from teens to individuals in their mid-50s, doctors told the station. Some of them were so sick that they had to be watched to keep from harming themselves.

Toxicology tests will determine whether all the drugs came from the same batch, according to police. Authorities will also investigate whether the K2 was laced with other drugs.

K2 is difficult to regulate because makers change the ingredients often, Stacey Davis, director of prevention programs for the Council on Alcohol and Drug Abuse in Dallas, told WFAA in a separate report.

“The compound is changed,” Davis told the station. “And it’s not illegal, because they have not banned that compilation of the drug.”

Still, some municipalities have enacted bans on K2 and other synthetic substances.

In 2013, three deaths in Colorado were investigated for possible connections to synthetic marijuana use, prompting officials to call for people to "stop using [the drug] and destroy it."