About one of every three people will need mental health services at some point in life, and psychiatric illnesses are the most disabling group of illnesses in the world today. So say Dr. Eugene H. Rubin and Dr. Charles F. Zorumski in their new book, “Demystifying Psychiatry: A Resource for Patients and Families” (Oxford University Press).

Together, these physicians have more than 50 years of experience treating psychiatric patients and helping patients’ families. Both are affiliated with the Washington University School of Medicine and both say that psychiatric disorders often are “under-diagnosed, poorly treated and highly stigmatized.”

Rubin, 60, earned his bachelor’s degree at the University of Rochester in Rochester, N.Y. At Washington University School of Medicine, he then earned a doctorate in pharmacology and a medical degree, and he also completed his residency training at the school. In 2009, the school honored Rubin with a Distinguished Educator Award.

Asked what drew him to his profession, Rubin replied, “I have always been interested in normal and abnormal behaviors. I was a psychology major and math minor before neuroscience was a field. The medical model approach at Washington University is why I am here–we look at psychiatric illnesses through testing and research, we gain new knowledge and we advance treatments.”

Rubin made time recently to talk about his new book, the third he has co-authored with Zorumski.

Why did you write this book?

To raise awareness. Many times when a person with a psychiatric illness goes to see a general doctor, that doctor may not ask questions to screen for common disorders, disorders as common and as significant as depression or alcohol dependence. If the doctor does not ask directly, the doctor may not pick up on these illnesses in a brief eight-minute interview.

Why would a doctor not ask?

There is no incentive for a doctor to open that can of worms. Yet if someone has signs of depression, that should be pursued. Psychiatric illnesses as a group lead to major causes of death–and psychiatric illnesses also are the most disabling of all medical diseases.

What might a patient say to open the conversation?

Unless someone jumps to the head of the line and says something to the doctor about not eating, not sleeping or feeling that life is not worth living, most doctors won’t ask the right questions. Patients need time with their doctors, and they need to be listened to.

Are those symptoms always indicative of serious illness?

With many psychiatric disorders, people do well throughout their lives, but they may require treatment. It may be something as simple as a psychotherapy booster session every six months or a prescription for lithium. Or the patient may need continuing exercise, good nutrition –some lifestyle changes that result in good, normal rhythms of sleeping and of eating healthy meals.

What if a person has more significant symptoms?

If a person is overtly psychotic — hearing voices or seeing visions — usually a family member brings that person to a doctor. Those symptoms are not ignored. In more severe instances – schizophrenia, bipolar disorder or dementia – some internists are uncomfortable treating those, or don’t know how to treat them.

Are patients always aware of their own illness?

No. One major difference between psychiatric illnesses and other medical illnesses is that as the psychiatric illness become more serious, the brain loses insight. Instead of thinking, ‘Oh my gosh–I’m getting depressed, things are going badly,’ you lose insight and begin to think, ‘I am a failure, a worthless human being.’

So depression may be more serious than a person realizes?

Yes. We are just starting to understand the mechanism in the brain that makes this possible. And depression frequently begins when you are young. It comes and goes, sometimes interfering with relationships and jobs. Depression can be disabling for 50 years or longer.

And all this is in your new book?

The book lays out the nuts and bolts of what psychiatric illnesses are, the different approaches to treatment and what the future holds in terms of research and health care delivery. Much of the pubic and some physicians are uncertain about these illnesses, and yet psychiatric disorders influence so many people — if not the person in mirror, then someone close to them.

Eugene H. Rubin, M.D.

WORK: Professor of psychiatry at Washington University School of Medicine and vice chairman for education, department of psychiatry.

HOME: University City

FAMILY: Married to Dottie Kinscherf, residency director/coordinator in the department of psychiatry at Washington University School of Medicine. They have a son, 28, and a daughter, 24, who live on the West Coast.

HOBBIES: Going to the gym, playing table tennis, taking walks, watching movies, spending time with his wife and children.

PERSONAL ACCOMPLISHMENT: Along with Dr. Charles F. Zorumski, Rubin is the co-author of “Demystifying Psychiatry: A Resource for Patients and Families” (Oxford University Press).