Ask someone to recite the symptoms of Lyme disease, and you'll probably hear all the classic signs: bull's eye rash, fever and aching joints.

But what about depression, memory loss and other cognitive disorders?

Surprisingly, Lyme disease - in its chronic form - can also be the culprit for a host of psychiatric problems in anywhere from 15 to 40 per cent of cases.

Island psychiatrist Dr. Charles Silberstein said that he now routinely sends patients suffering from depression to the hospital lab for a Lyme disease blood test.

"In my practice, I see people who present with symptoms of depression who turn out to have chronic Lyme never diagnosed," he said in a telephone interview yesterday. "Chronic fatigue, low moods, decreased motivation and drive are all symptoms of chronic Lyme."

"You wouldn't think about that in a region that's not endemic with Lyme, but the prevalence here is extraordinary," he added.

The Vineyard boasts the second highest rate of Lyme disease incidence in the state, trailing only behind Nantucket. In 2000, there were 33 confirmed cases on the Island.

Experts agree that Lyme disease is notoriously under-reported. According to the Columbia University psychiatrist heading up a new Lyme study that will recruit Island participants this Saturday, only 10 per cent of all cases are actually reported to the public health agencies.

For all the publicity about Lyme disease, the focus has been mostly on prevention and quick treatment at the first signs of infection. Those are the best scenarios, since the disease is best treated early on.

But chronic Lyme disease appears to come from cases that weren't treated quickly. Even today, scientists know remarkably little - and differ widely - about what exactly chronic Lyme disease is and how they should treat it.

Dr. Brian Fallon's focus is squarely on chronic Lyme and its effects on the brain. Three years ago, researchers at Columbia won a $4.7 million grant from the National Institutes of Health aimed at unlocking the mysteries of chronic Lyme disease.

His team is coming to the Vineyard this Saturday with a special invitation to Islanders between the ages of 18 and 65 who have already undergone a round of intravenous antibiotic treatment for Lyme but are still having memory problems.

A blood test from noon to 4 p.m. at the Tisbury Senior Center will be used to screen people for the study. If selected, participants would be given a 10-week treatment of an intravenous antibiotic called Rocephin. The one catch is that this is also a placebo study, meaning that one of three participants won't be injected with an antibiotic, but a placebo.

At the end of six months, the participants who received a placebo would be given a six-week treatment, according to Dr. Fallon.

It won't be easy to qualify for the study. The blood tests must also show a current infection. So far, only one out of every 120 people tested have made the final cut to take part in the study.

Dr. Fallon, the study's lead investigator, is counting on better odds in places such as the Vineyard and Nantucket. For would-be participants, the pay-off could be a ticket to a pre-infection status and an enormous cost-savings.

Cost of the antibiotics alone is nearly $2,000 a week. The study would also cover most of the cost of traveling to New York City four times over 24 weeks.

The goals of the study sound simple. Dr. Fallon wants to know not only whether 10 weeks of IV antibiotic treatment will improve the health of patients, but also why they have had persistent symptoms in the first place.

That second question is what makes this chronic Lyme study different from some of the others that have arrived on the Island, trolling for patients. This study will include a series of brain-imaging tests known as positron emission tomography (PET).

"As opposed to MRI that looks at the structure, this is imaging of the functioning of the brain, the blood flow and the nerve cells," said Dr. Fallon in a telephone interview last Friday with the Gazette.

"We're trying to determine why patients have cognitive problems, memory and verbal fluency problems," he added. "Nobody really knows: Is it primarily with Lyme a blood flow or a nerve tissue functioning problem?"

If the mental effects of chronic Lyme are less well known among the general public, that's not the case in the medical profession.

From the very beginning, scientists from Yale University who discovered Lyme disease in the coastal town of Old Lyme, Conn., were documenting mood swings and irritability in almost 35 per cent of the original cases, said Dr. Fallon.

Dr. Fallon also pointed to the history books to show the similarities between Lyme disease and syphilis, a spiral-shaped bacteria like the Lyme organism. One of the first symptoms of syphilis was also a rash, and left untreated, its victim frequently suffered from psychiatric problems, ranging from memory loss to mania, psychosis and dementia.

"In the 1930s, 40 per cent of the people in mental hospitals were patients with syphilis," said Dr. Fallon.

With chronic Lyme disease, it can take more than a year for cognitive symptoms to appear, according to the information on the Columbia web site,

Sleep disturbances and headaches can be followed by brain fog, a hypersensitivity to light, spatial orientation problems and stuttering or reversing of words, the web site also stated.

If chronic Lyme sufferers cannot make it to the screening, they are asked to contact the Columbia Lyme program at 212- 543-6510 or through e-mail at