The "bible"of American psychiatry — a manual of mental health used around the world by doctors, consumers and insurance providers — has come under fire from a growing group of psychologists who worry that proposed revisions will feed into a culture of overdiagnosing, and overtreating, otherwise healthy people.

The Diagnostic and Statistical Manual of Mental Disorders, or the DSM, is undergoing its fifth major revision in the more than 60 years since it was first published by the American Psychiatric Association. The last update was in 1994, and the new manual is expected to be released in spring 2013.

Revisions to the DSM are often hotly debated, but after two decades of major, and frequently controversial, shifts in how mental health problems are diagnosed and treated in the United States, this latest update has become especially contentious, many mental health providers say.

Last month a group of psychologists with the Society for Humanistic Psychology posted a petition against many of the suggested DSM revisions, citing what they see as a broadening of the definition of mental health disorders, which, in turn, would lead to overtreatment with drugs. The petition now has more than 7,000 signatures, and it won the support of San Francisco's Saybrook University, with roughly 60 faculty members who emphasize a holistic approach to treating mental illnesses.

"There's this propensity to push pills instead of looking at what's really going on with the person,"said Saybrook President Mark Schulman. The APA has posted an online response to the petition, welcoming critiques to and comments on the proposed revisions. Their response notes that the manual is still a work in progress.

Since the last diagnostic manual update, research has increasingly pointed to biological causes for a wide variety of mental health conditions and, in response, treatment has turned toward pharmacological answers, some psychologists say. Drugs are being used to solve mental health problems that aren't problems at all, they add.

Therapy is still popular, but part of the problem is that there simply aren't enough trained counselors to fill the mental health need. Patients are turning to primary care doctors, but because many doctors rely on the DSM to help them understand and diagnose mental health problems, it's critical that the manual be as accurate and science-based as possible, say psychologists who have signed the petition.

Critics of the DSM update say that the task force assigned to make the revisions has suggested broadening the definitions of too many mental health problems. Grief after the death of a loved one, for example, may be included under the diagnosis of major depressive disorder. That means a person's grief could be labeled a pathological disorder, and not a normal human experience, said psychologist Brent Robbins, a professor at Point Park University in Pittsburgh and an author of the petition.

Dr. James Scully, medical director of the APA, said there's no doubt that the past two decades of research into mental health has opened the door to biological causes of disorders, but that doesn't mean that drugs are the obvious answer. And the new DSM, he said, will reflect that distinction.

"It's not the proposal to make it all psycho-biological. Even to know that it's biological does not mean the answer is pharmacology," Scully said.

(Email Erin Allday at eallday@sfchronicle.com.)