"This is a major form of acting out," she said. "She's not using words and language as a way to express what's going on. She's doing things -- the crotch shots, shaving her head, the tattoos. It says that she hasn't learned to assert herself and become independent through self assertion rather than through acting out.
"The hair represents the stylists, the handlers, people who are in control of her life and manage her looks," Marshall added. "Now she's saying, I'm in charge of my looks."
By going bald, Spears may be seeking a rebirth.
"I think the shaving of her hair is a fresh start, is a new beginning, taking matters into her own hands, doing it her own way," Marshall said. "I think most importantly, in her own maybe distorted way, it's getting rid of the superficial and getting down to something deeper."
According to the entertainment news show "Access Hollywood," on Friday, a representative from Spears' record label admitted rumors that the pop star checked into a rehab facility last week but left quickly were true.
ABC News has not confirmed reports of the alleged rehab visit, but if they're true, Marshall said that Spears' head shaving and tattooing could be her way of rebelling against rehab.
"Like her hair, which represents other people telling her what to do, rehab is experienced by her as one more act of rote conformity. So she rebelled by walking out, shaving her hair, getting the tattoos," she said.
Marshall's prescription for Britney is simple: therapy and time away from Hollywood.
"I think psychotherapy would be the best thing for her," she said. "Seek therapy, have her own autonomous life … step out of the limelight for a while."
Salon owner Tognozzi hopes Spears' mom, Lynne, will step in and take charge of her daughter and her young sons.
"I would say, 'Please take your daughter and get her off the media circus, and just take her home for a while, and take care of her and her babies,'" Tognozzi told "Extra."
In fact, Lynne may be coming to her daughter's rescue. Perezhilton.com reports that Spears' mom was spotted on a flight from her Louisiana home to Los Angeles on Saturday and gave the paparazzi a "thumbs-up" signal.
Even if she does get help, Spears' head-shaving is likely to haunt her long after her locks grow back. Marshall believes that if going bald can help Spears discover her true self, then picking up the buzzer may have been a good move.
"If the cutting off of the hair is getting rid of the superficial, getting down to something more meaningful, then I think everybody should back off and let her get down to something deeper," she said.