Psychological states and neuropsychological performances in chronic Lyme disease

The neuropsychiatric sequelae of chronic Lyme disease remains unclear. This study sought to characterize the psychological status of a group of participants who met criteria for post-Lyme syndrome (PLS). These measures were then used to examine the influence of psychological status on neuropsychological performances. Thirty PLS participants completed a structured psychiatric interview, the Positive and Negative Affect Schedule, the Lyme Symptom Checklist, and a battery of neuropsychological tests. As a group, the PLS participants did not appear to have an elevated incidence of psychiatric disorders, and psychiatric history was not useful for understanding neuropsychological performances or symptom reports. The mood of the PLS participants was characterized by lowered levels of positive affect (PA) and typical levels of negative affect. This combination can be distinguished from depression and is consistent with previous findings of affect patterns in individuals with chronic fatigue syndrome. PA was also linked to both total symptom severity and severity of cognitive complaints, but not to duration of illness, neurological manifestations at initial diagnosis, or treatment history. Relative to published normative data, neuropsychological performances were not in the impaired range on any measure. Neither psychological status nor symptom report were useful for understanding any aspect of cognitive functioning. It is concluded that decreased PA is the most useful marker of psychological functioning in PLS.