Dr. Laura Berman Says She 'Regularly' Tested Her Son for Drugs Before His Fatal Overdose

Dr. Laura Berman is opening up about her 16-year-old son Sammy after he died from an accidental drug overdose. On Tuesday's episode of The Dr. Oz Show, Berman said she and her husband, Samuel Chapman, were "regularly" testing Sammy for drugs after discovering he had "experimented with cannabis several months prior."

Berman and Chapman said Sammy had "never done anything beyond" cannabis and that they had no inclination he was experimenting with any other drugs. Berman, 51, said that they "came down very firmly" on him and had a "zero-tolerance" when it came to drugs. "We even got him a drug counselor that he met with and continued to," she said in the sneak peek from PEOPLE. "There was also a therapist that he met with once a week; we tested him regularly."

Berman, a sex and relationship therapist who hosts In the Bedroom on OWN, the Oprah Winfrey Network, announced earlier this month on Instagram that her son died, revealing at the time that "a drug dealer connected with him on Snapchat and give him [fentanyl] laced Xanax, and he overdosed in his room." Berman told Dr. Oz that she believes Sammy obtained the drugs from the drug dealer while he was either on a walk or when the family was sleeping.

"What we were able to piece together after the fact from his friends was that we believe that — the toxicology reports will tell us exactly what he took — but that we believe it was probably he got it on Wednesday night. He took it on Sunday," she explains. "He just went outside either when we were sleeping or during the day maybe when he took a walk and he met this drug dealer that he had connected with on Snapchat and got it that way."

Fentanyl, a fast-acting opioid, is 80 times as potent as morphine and hundreds of times more potent than heroin, the Centers for Disease Control and Prevention estimates. Classified as a Schedule II drug by the federal government, its medical uses are usually for pain management after surgery or chronic pain.

Snapchat has said that the company is "committed to working together with law enforcement in this case and in all instances where Snapchat is used for illegal purposes." The company says it has "zero tolerance for using Snapchat to buy illegal drugs."

Since Sammy's death in early February, Berman and Chapman have spoken out one other time on the Today show. Berman told NBC News' Kate Snow that she "didn't intend for us to be on the news, I just felt helpless. All I was thinking about is that this couldn't happen again and I was so furious and helpless."

The parents insist that there is "no way" Sammy knew the drugs he bought had fentanyl in them. "Each different drug had a different color, the way a kid would love to see it," Chapman said of the "menu" Sammy used to purchase the drugs on the social media app.