Are cognitive and olfactory dysfunctions in neuropsychiatric lupus erythematosus dependent on anxiety or depression?

Depressed mood and cognitive impairments are common findings in systemic lupus erythematosus (SLE) and frequently coexist. We assessed the neuropsychological functioning of patients with SLE and investigated its association with psychopathological symptoms.

A total of 85 patients with SLE (28 with neuropsychiatric syndromes: NPSLE) and 85 healthy control subjects with similar demographic characteristics were asked to perform a series of neuropsychological tests. A self-report questionnaire (the Hospital Anxiety and Depression Scale) was used to screen for psychopathology symptoms. Patients with SLE underwent a neurological examination.

Patients with NPSLE were more depressed and were more frequently impaired in cognitive and olfactory functions than controls or non-NPSLE patients. The NPSLE group remained statistically different from the other 2 groups on a series of neuropsychological measures (the Auditory Verbal Learning Test, Trail Making Test - Part A, Nine-Hole Peg Test, and Brief Smell Identification Test) even after control for elevated anxiety and depressed mood. Non-NPSLE and control groups were not significantly different regarding either psychopathological symptoms or neuropsychological functioning.

Verbal memory, psychomotor speed, and olfaction are particularly vulnerable to dysfunction in NPSLE; impairment in these neuropsychological domains is not completely explained by psychopathology symptoms.