P&S Journal: Winter 1998, Vol.18, No.1
Lyme Disease and Psychiatric Disorders
Brain scans and neuropsychiatric tests can help doctors determine whether psychiatric problems are a result of Lyme disease or a primary psychiatric disorder, P&S research has demonstrated.
The findings are important because many people with Lyme disease do not exhibit the classic rash and flu-like symptoms but later experience secondary symptoms, such as depression, panic attacks, paranoia, personality changes, mood swings, attention problems, or short-term memory loss. These symptoms can be easily attributed to primary psychiatric disorders, especially when the patient's clinical presentation does not include joint swelling or Bell's palsy, two of the more commonly recognized signs of Lyme disease, and when standard laboratory tests for the disease prove inconclusive, which can be the case in chronic Lyme disease.
"Such mislabeling may have particularly detrimental effects on the Lyme disease patient, as a delay in diagnosis and treatment may result in a curable acute infection becoming a chronic, treatment-refractory illness, wrote study leader Dr. Brian Fallon, associate professor of clinical psychiatry at P&S, in an issue of Clinical Infectious Diseases.
In an earlier study, Dr. Fallon found that depression was three times more common in patients with Lyme disease than in patients with comparable diseases (lupus, rheumatoid arthritis, and osteoarthritis). "That was surprising to us, and it suggested that there is something going on in the brain of Lyme patients that is directly causing the depression.
Dr. Fallon, in collaboration with Dr. Ronald Van Heertum, Dr. Jeffrey J. Plutchok and their colleagues in radiology, subsequently found that at least half of patients with chronic Lyme disease have brain abnormalities, evident on SPECT (single photon emission computed tomography) scans. "The specific appearance is a heterogeneous pattern of decreased perfusion," says Dr. Fallon, who is also director of the Lyme disease research program at the New York State Psychiatric Institute.
In a follow-up study, the researchers found that blood flow to the affected areas of the brain improved in approximately half of the patients who were given intravenous antibiotic treatments.
Since this pattern of decreased brain perfusion is seen in patients with other diseases, including HIV encephalopathy, chronic cocaine abuse, chronic fatigue syndrome, and lupus, SPECT imaging alone cannot be used to confirm a diagnosis of chronic Lyme disease, says Dr. Fallon. A thorough evaluation should include a physical examination and standard laboratory tests plus formal neuropsychological testing, such as the Wechsler Memory Scale, and brain imaging, such as MRI, SPECT, or PET scanning.
When should a doctor suspect that a neuropsychiatric problem is the result of Lyme disease? If the only thing a patient has is depression or anxiety, Lyme disease would be low on the list of possibilities, Dr. Fallon says. "But if he or she has mood swings, attention problems, or memory problems, as well as some joint pains and some numbness and tingling, you have to consider Lyme disease, especially in the greater New York area, where it is endemic. And anytime you see a young patient with memory problems, then you have to start wondering: Could this be Lyme disease?