Some doctors hope the newest edition of psychiatry's bible is the last of its kind.

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders or DSM comes out on Saturday at the American Psychiatric Association's annual meeting in San Francisco. It was controversial before the ink dried.

It's the first revision since 1994 to what's long been considered the authoritative source in North America for diagnosing mental problems.

But Dr. Thomas Insel, director of the U.S. National Institute of Mental Health, complains that the book lacks scientific validity.

On CBC Radio's The Current on Friday, Insel said the method used to classify mental illnesses in the DSM-5 is faulty because it relies on clusters of symptoms rather than scientific data.

Under the new definitions, grief soon after a loved one's death could be considered major depression. Certain "senior moments" become labelled as "mild neurocognitive disorder."

This week, Insel and the psychiatrists group issued an olive branch in the form of a joint statement saying they have similar goals for improving the diagnosis and treatment of mental illness.

Dr. Michael First, a professor of clinical psychiatry at Columbia University and an editorial consultant for the latest issue, acknowledged it is imperfect. First said it's the best available model for clinical work because the science is not yet advanced enough to offer an alternative.

The 947-page volume sells for $199 US.  

With files from Associated Press