The aims of this study were to follow a cohort of HIV-infected individuals for 2 years to assess changes in depression and neuropsychological performance over time, to explore the relationship between depression, HIV illness and neuropsychological performance, and to examine the natural history of the effect of highly active antiretroviral therapy (HAART) on depression and neurocognitive performance.

HIV-seropositive out-patients were assessed at baseline and at 2-year follow-up. At each assessment, patients were assessed for depression [using the Beck Depression Inventory (BDI) and Structured Clinical Interview (SCID-CV)] and completed a battery of neuropsychological tests including the Cambridge Neuropsychological Test Automated Battery (CANTAB) and the Hopkins HIV Dementia Scale (HDS).

At baseline, 34.8% scored > or =14 on the BDI [> or =14 suggests depressive symptoms (DS)]. The SCID-CV revealed that 27% of participants met the criteria for current mood disorder. Seven per cent of the participants' scores on the HDS indicated HIV-associated cognitive changes. Eighty participants were re-tested at 2-year follow-up and were split into two groups based on BDI scores at baseline. CANTAB results revealed that the cohort were significantly impaired on nine of 10 measures compared with age-matched normative data. Neurocognitive performance significantly improved for participants with no DS at baseline, whereas participants with DS at baseline did not show as much improvement. Multivariate analysis revealed that 40% of the change in cognitive performance was attributable to the variables age, AIDS and HAART regimen.

These results suggest a significant decline in depression scores and an improvement in several neurocognitive domains over time, with a relationship between HIV illness, HAART, symptoms of depression and neurocognitive performance.