It's difficult to estimate how many people have eating disorders, simply because sufferers are so good at hiding them.

Eating disorders generally take one of three forms: anorexia nervosa, bulimia nervosa and binge-eating disorder. Those with anorexia are usually malnourished and emaciated, but stop eating or severely restrict food because they think they are fat. Bulimics, who purge or exercise excessively after eating, can be the most successful at hiding their problem because they often are at a normal weight or even a little overweight. Binge-eaters, the most recently recognized form of eating disorder, eat compulsively without compensating behavior, and might be overweight or obese.

Experts say seeking professional help with an eating disorder, particularly anorexia, is usually the best course. But it can take months away from work or school, and isn't always covered by health insurance.

Dr. Pauline Powers, a psychiatrist who has been treating eating disorders for more than 40 years, says she suspects many people try the self-help route. "So many aren't in treatment, aren't reporting it to their doctors,'' said Powers, who retired from USF Health's psychiatry division in 2013 and is now in private practice in Temple Terrace and Clearwater.

"Questions about disordered eating need to be a standard part of primary care . . . I think it should be done like asking about diabetes and blood pressure," she said.

Powers recently spoke with the Times about what's new in treatment and research.

Can you know who will succeed with self-help?

Generally, the longer the eating disorder has been going on, the more likely they will need to be hospitalized. This is certainly true with anorexia because it also usually has other complicating conditions like depression, substance abuse or bipolar disorder. Also, patients who have failed at conservative treatment attempts, and those who don't have a network of family members who can form a team to watch the patient, usually need hospitalization.

It depends on how committed patients are to getting better. Some, who have had an eating disorder for years, realize it doesn't make sense anymore and they want to get better.

What's new in treatment?

Something we call family-based treatment for adolescents with anorexia. What we do is teach the family, primarily the parents, how to get patients to eat so patients can stay at home rather than having to be hospitalized. Some can even continue going to school. We are finding that this doesn't work well with adults, but teens and adolescents under 18 are still under their parent's control and respond well to this. It takes a lot of patient visits, usually one — but sometimes as many as three — therapy sessions a week. But in the long run it will be much less expensive for families and may get patients into treatment sooner. And we know the sooner we start treatment after onset, the better the outcome.

Any new medications?

We still only have one drug FDA-approved for bulimia, Prozac; it's not wonderful but it helps some, especially when combined with cognitive behavioral therapy. The theory is that it raises serotonin in the brain, which relieves depression, which may help improve the eating disorder.

Are most patients still women ages 25 and younger?

Yes, but we are seeing more and more men with eating disorders. And we don't suspect that in men, so they tend to get to treatment late. About a third of patients with anorexia are men. Bulimia is also quite common in men. Especially men in military service, where there can be rigid rules about weight and fitness. We have at least one study that says eating disorders are more common in male service personnel than in the general (male) population.

We're also hearing about more middle-aged and elderly women with eating disorders.

What's new in research?

It looks like there's a whole circuit in the brain that goes wrong in people with eating disorders. We want to understand what happens to this circuit, what keeps them from eating when they get hungry. We may also learn more about eating disorders from research into alcoholism and obesity.

Contact Irene Maher at imaher@tampabay.com.