The clinical and social consequences of AIDS dementia complex/HIV-1 associated cognitive/motor complex (ADC/HACC) in drug users have not been well documented. The value of prospective serial neuropsychological, neuroradiological and neurophysiological measurements to assist diagnosis of ADC/HACC in patients with premorbid personality disorder and intercurrent drug use is demonstrated. The psychosocial problems resulting from ADC/HACC with respect to community care and the location of hospitalization is considered. The relevance of the 1984 Mental Health Act (Scotland) with regard to drug users with ADC/HACC is discussed.