WESTPORT — Though Mel Schwartz is 66 years old, he has no plans to retire anytime soon.

As a psychotherapist and marriage counselor, Schwartz runs a private practice out of Westport where he’s lived for 12 years. On Sept. 1, his second book “The Possibility Principle” was released. The self-help book explores how quantum physics can improve the way people think and live their lives, helping them overcome depression, anxiety and relationship woes.

However, Schwartz said he wasn’t a physics student, nor did he initially study to become a psychotherapist.

Up until he was in his forties, Schwartz worked in business but found it wasn’t rewarding. In what he describes as a “defining moment,” he decided to close his business and enroll in a masters program at Columbia University to become a psychotherapist so he could do something he felt could really help other people.

Schwartz also found the inspiration for his latest book around the same time. Going through a divorce, he decided to take a bike ride on a spring afternoon and had a panic attack in the middle of it. He went home and perused his book shelf, settling on a book by a quantum physicist to help him calm down.

“I noticed 10 to 15 minutes into it, I was calm,” he said. “My anxiety retreated. If it did that for me, why don’t I continue that research?”

Schwartz began incorporating the principles into his own work with his clients.

“It’s not about the science, but what the science tells us,” he said. “Science tells us reality is completely unpredictable. When people create too much certainty, it creates anxiety. I see it all the time in therapy. Quantum physics tells us reality is uncertain. If we try to be free of uncertainty, we live in fear. But what if we embrace uncertainty?”

The idea of embracing uncertainty is one Schwartz tells his clients and is also a focal point in his new book.

In addition to psychotherapy, Schwartz offers marriage counseling and uses the principle of connectivity — building relationships through shared experiences — to help people thrive in their relationships. Schwartz uses the principle to help people develop a sense of compassion toward their partner, as well as focusing on what they’re feeling rather than accusing their partner of wrongdoing.

“If I say I feel, I can’t be told I’m wrong for what I feel,” he said. “These principles set the stage for living life without feat.”

Schwartz said through employing these principles, clients can change their thinking and help overcome anxiety and depression. And through learning to see your thoughts without becoming them — a take on a quantum physics theory — clients and readers can get a hold on feelings of fear or stress.

“The relationship that is going to impact you the most is the relationship with your thoughts,” he said. “You need to make them your ally.”

In the 22 years he’s been practicing, Schwartz said he’s seen a hike in people diagnosed with mental health disorders, something he says can be harmful.

“Coping (with mental health disorders) is an important first step but I’m a lot more optimistic than simply managing,” he said. “I’ve helped a number of people overcome anxiety. I’m an optimist. I don’t believe in managing. I believe in thriving.”

In addition to running practices in Westport and New York City, Schwartz writes a blog, “A Shift of Mind,” and has also had his work featured in “Psychology Today.”

He moved to Westport after visiting the town while speaking about his first book, “The Art of Intimacy, The Pleasure of Passion,” published in 1999. It was during that trip he fell in love with the town, as well as met his partner, Leslie, whom he resides with today. Drawn to the town’s coastlines, the couple lives on the beach and enjoys the town’s great restaurants.

“There’s a dynamic quality to Westport,” he said.

ekayata@hearstmediact.com; @erin_kayata