DEAR DR. ROACH: My daughter is a registered nurse, and tells me that when getting blood tests, it is not necessary to fast eight to 12 hours even though my doctor says to do so. Four hours is enough, she claims. Is this true, or is my daughter trying to be a doctor, if you know what I mean? — L.C.

ANSWER: I probably agree with your daughter the nurse more than I do with your doctor in this case. Most routine blood testing does not require fasting. There is controversy about whether cholesterol testing is best done fasting or not: Most recent evidence suggests that fasting is not necessary. However, many physicians still continue to use fasting levels, as that is what they are used to. Nonfasting numbers may reflect the true state of risk to the arteries more so than fasting levels.

A few seldom-ordered tests, such as insulin levels, may need to be drawn precisely a certain period of time after feeding to be able to interpret them. In most cases, your daughter is probably right that prolonged fasting is unnecessary. I still recommend following your doctor’s orders.

Your daughter is providing you with up-to-date medical knowledge. Any nurse or doctor should do the same.

DEAR DR. ROACH: Can hypnosis bring a person out of depression? — J.C.A.

ANSWER: There is limited evidence that hypnosis, or hypnotherapy, is a potential treatment for depression. A 2010 study of 84 patients showed that approximately equal benefit of hypnotherapy compared with cognitive behavioral therapy, which is an accepted treatment for depression. I did not find a study comparing hypnotherapy with medication treatment. However, it may be worth considering hypnotherapy in someone with mild depression and no good response to other treatments or who is unwilling to use medication. I would not recommend hypnotherapy for severe depression.

For someone interested in this kind of therapy, finding a qualified therapist for hypnosis may not be easy. One suggestion is to look for membership in the American Society of Clinical Hypnosis or the Society for Clinical and Experimental Hypnosis.

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