This research is a cross-sectional study to determine the frequency of neurocognitive impairment and psychiatric comorbidity among Thais maintained on highly active antiretroviral therapy (HAART) with undetectable plasma human immunodeficiency virus (HIV) RNA in the 2NN Cohort. Sixty-four subjects were evaluated with neurological examinations, neuropsychological testing, and psychiatric questionnaires. Twenty-four subjects (37.5%) were found to have neurocognitive impairment, with 13 (20.3%), 10 (15.6%), and 1 (1.6%) classified as asymptomatic neurocognitive disorder (ANI), mild neurocognitive disorder (MND), and HIV-associated dementia (HAD), respectively. Three subjects (4.7%) had depression and no cases had significant symptoms of anxiety. A notable proportion of well-controlled individuals exhibited neurocognitive impairment. Anxiety and depression were uncommon.