DEAR ABBY: In past months, some of the letters in your column have dealt with forgetfulness and aging. I would like to inform your readers about a research study designed to address the issue of memory loss found in normal aging compared to that seen in early Alzheimer's disease.

The Memory Impairment Study is taking place at 60 to 80 sites across the United States and Canada, and holds promise for medical intervention against the development of Alzheimer's disease. The study will investigate two treatments that will, we hope, lessen the likelihood of developing Alzheimer's disease in people with a condition known as mild cognitive impairment.

Mild cognitive impairment refers to a type of memory loss beyond that which is expected during the course of normal aging. Symptoms typically include forgetting recent experiences on an increasingly frequent basis. Persons with mild cognitive impairment are otherwise normal, engage in the usual activities of daily living, and do NOT have a diagnosis of dementia or Alzheimer's disease. Nevertheless, it appears that such individuals are at higher risk for developing Alzheimer's disease.

For the study, we are looking for men and women between the ages of 55 and 90 who are in good general health but are forgetful for their age. They must have a partner who is familiar with them and can accompany them to their clinic visits. The study will run for three years. Clinic visits occur approximately every six months. We will be testing two treatments in comparison to a placebo (an inactive pill).

Volunteers for this study are key to helping us provide hope for the millions of individuals affected by Alzheimer's disease.

We greatly appreciate your support for research in Alzheimer's disease and hope your readers will contact us if interested. -- RONALD C. PETERSEN, M.D., DIRECTOR, ALZHEIMER'S DISEASE RESEARCH CENTER, MAYO CLINIC, ROCHESTER, MINN.

DEAR DR. PETERSEN: Thank you for a fascinating letter. I'm sure that many will be interested in the direction that the latest, cutting-edge research is taking in the search for a cure for Alzheimer's disease. As the population of our country ages, it's a problem that will affect an increasing number of individuals and families.

According to the latest figures from the Alzheimer's Association, approximately 4 million Americans have Alzheimer's disease. Fourteen million Americans will have it by the year 2050, unless a cure or prevention is found.

Readers can obtain more information about the study by calling (888) 455-0655 or by visiting the Memory Impairment Study Web site at: www.memorystudy.org.

DEAR ABBY: Some of my friends tend to be a bit immature at times, about both serious and minor situations. I try to give good information if they don't know what to do, or if they're considering something foolish to get through their crisis.

Is there a certain approach or a time that is best to give out my information so that they take it as seriously as I would take it? -- KELLY IN PORT WASHINGTON, N.Y.

DEAR KELLY: Yes. The most unwelcome advice is that which is unasked for, so volunteer your information only when asked. The exception would be a life-threatening situation.

CONFIDENTIAL TO MY JEWISH READERS: Happy Hanukkah, one and all!

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DEAR ABBY: After reading your column about outrageous mothers-in-law, I had to write. When I was 17, I married my high school sweetheart. He was only 20. We were entirely too young to get married. However, his mother never said a negative word about it. In fact, she was our most ardent supporter.

The following year, we had a baby boy. We were too immature to have children, but my mother-in-law never said an unkind word. She was extremely kind and generous to my son and to me as well. She never once criticized the way I took care of the baby. When she came to visit, she asked me nicely what I wanted her to do, and then she did it. When I think of this now, it brings a smile. I was only 19 and knew nothing about babies, but still she respected my wishes as the mother of this child. If she had a negative opinion about me, she kept it to herself.

After a few years, the marriage fell apart. The subsequent divorce and custody battle got very ugly. My mother-in-law never took sides.

I am now happily remarried and live about 3,000 miles away from my former mother-in-law. My former husband has also remarried. Neither of us has had any more children, so my 12-year-old son is my former mother-in-law's only grandchild. He visits her every summer, and I keep her up-to-date as much as possible about his activities via e-mail and pictures.

Sometimes people are curious about why I work so hard to keep this connection to my ex-husband's family. After all, according to the world's expectations, we're supposed to "hate" each other, right? Wrong! This lady is a gem. She's a sterling example of how people should treat each other.

She and I had a long talk this summer about this very subject. I told her that I do not "own" my son. He's part of her, too. And I would be doing a grave disservice as a parent to deny my child the gift of knowing this wonderful grandma. I only hope that someday I will be as terrific a mother-in-law and grandmother as she is. -- RACHAEL IN CALIFORNIA

DEAR RACHAEL: I'm sure you will be -- because you fully appreciate the maturity, generosity and diplomacy that are required to fulfill those roles. Many people could take a lesson from your former mother-in-law.

DEAR ABBY: I read with interest the letter about checking to see that a security whistle is in working order. Many years ago, I had a persistent obscene caller. Hanging up on him did not dampen his enthusiasm, so I decided to blow a shrill whistle during his next call. As expected, he called late one night, so I grabbed the whistle and began to blow.

Instead of making a shrill noise, the whistle made an odd rattling sound. Undaunted, I continued trying to whistle -- but I began to laugh at the pathetic noise. A moment later, the caller asked in an incredulous voice, "What on earth is that noise?" I explained, laughing, "I'm trying to blow a whistle in your ear!" With that, he howled with laughter, hung up and never called back. -- STILL LAUGHING IN DALLAS

DEAR STILL LAUGHING: Congratulations. Even though the whistle malfunctioned, you succeeded in "blowing off" the obscene caller. That's a victory.

To order "How to Write Letters for All Occasions," send a business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Letter Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)

DEAR ABBY: Please alert your readers to a problem of grave concern. (No pun intended.) "Club drugs" are becoming the "rave" with teens and young adults at all-night dance parties across the country. While those who use Ecstasy, GHB, Rohypnol -- to name only a few of these drugs -- may think they have no side effects, the reality is that these drugs are potentially life-threatening. Whether kids knowingly use these drugs or have them surreptitiously slipped into their drinks at "rave" parties, they can produce a range of effects -- including hallucinations, paranoia, amnesia and even death.

Ecstasy, which goes by several names including "X," "Adam" and "MDMA," is both a stimulant and a hallucinogen. People may use Ecstasy for energy to keep on dancing and improve their mood. However, this drug increases the heart rate and body temperature, occasionally to the point of heart and kidney failure. It also appears to diminish the sense of thirst, and Ecstasy users have died from acute dehydration.

In addition, brain-imaging studies have shown that frequent Ecstasy use may damage brain cells that produce serotonin, a natural chemical that is partly responsible for memory and mood. It is still not known if these cells can regenerate, so the memory loss -- and perhaps additional, still-to-be discovered serotonin-related impairments -- may be long-lasting or permanent.

GHB ("G," "liquid Ecstasy") and Rohypnol ("roofie," "Roche") have been associated with "date rape" and sexual assault cases around the country. These two drugs, which are colorless, odorless and tasteless, have been easily slipped in the drinks of unknowing victims. Because both GHB and Rohypnol cause sedation and produce amnesia, they often prevent a sexual assault victim from identifying and successfully prosecuting the perpetrator.

Widespread use of Ecstasy, GHB and Rohypnol is relatively recent. The worst effects of these drugs may be the ones that are not yet known. Researchers, supported by the National Institute of Drug Abuse, are studying "club drugs" with a sense of urgency. Although we still have much to learn about the effects of these drugs, we already know that they can be extremely harmful.

On Dec. 2, we will launch a National Club Drug Initiative that will include issuing a Community Drug Alert Bulletin explaining what science says about the effects of these drugs. In addition, we will be working with several national organizations to get the word out to parents, teens and others about the dangers of these drugs. We also have information about these and other drugs on our Web site at www.drugabuse.gov. Or, your readers can call (800) 729-6686 to request free copies of these materials. Thank you for your help in getting the word out, Abby. -- ALAN I. LESHNER, Ph.D., DIRECTOR, NATIONAL INSTITUTE OF DRUG ABUSE

DEAR DR. LESHNER: I applaud your research, and I'm pleased to help.

When will people learn that there is no free lunch? There is a price to pay for every mood-altering chemical people put into their bodies. One can only hope that the substance is not addictive and the effects aren't permanent. Years ago, many people thought that cocaine was not addictive. Then fortunes were lost and lives were ruined or lost when the opposite turned out to be true.

I hope your Web site will be visited by people of all ages. Young people need to know everything they can about what they are putting into their bodies so they can make informed judgments. And as to the "date rape" drugs -- it has reached the point that people should not drink beverages at clubs or parties unless they have opened the container themselves and had the beverages in their possession AT ALL TIMES.

Good advice for everyone -- teens to seniors -- is in "The Anger in All of Us and How to Deal With It." To order, send a business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Anger Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)