The Neurocognitive Sub-study of Encore1

The Neurocognitive Sub Study of Encore1:A Randomised, Double-Blind, Placebo-Controlled, Clinical Trial to Compare the Safety and Efficacy of Reduced Dose Efavirenz (EFV) With Standard Dose EFV Plus 2N(t)RTI in Antiretroviral-naïve HIV-Infected Individuals Over 96 Weeks A Randomised, Double-blind, Placebo-controlled, Clinical Trial to Compare the Safety and Efficacy of Reduced Dose Efavirenz (EFV) With Standard Dose EFV Plus Two Nucleotide Reverse Transcriptase Inhibitors (N(t)RTI) in Antiretroviral-naïve HIV-infected Individuals Over 96 Weeks

The purpose is to investigate whether HIV and HIV medication can affect certain areas of brain function. This study will look at possible changes in brain function including memory, concentration and thought processes to see if there are any differences between the two doses of efavirenz used in the Encore1 study and also the level of efavirenz in the blood

Inclusion Criteria:

• All subjects entering into the main study protocol at participating centres will be eligible to enter this sub-study.

Exclusion Criteria:

• Existing neurological brain disease
• Recent (<6months ) head injury
• Current major depression or psychosis
• Current alcohol abuse
• Intended use of recreational drugs during study period
• Uncontrolled medical conditions deemed to potentially interfere with cognitive function (e.g. uncontrolled diabetes, pyrexial illness, uraemia etc)