Reports have suggested that isoniazid treatment may be associated with poor concentration
and subtle reduction in memory. This study examines attentional function and processing speed
in a group of 25 adolescents who received isoniazid prophylaxis for at least 6 months. As
adolescents often face major educational assessment milestones, such cognitive side effects may
have important implications. Participants were assessed before treatment, 1 month into
treatment and at least 1 week after treatment cessation. Measures included the Paced Auditory
Serial Addition Test and subtests of the appropriate Wechsler scale sensitive to attention and
speed of information processing. Isoniazid does not appear to cause significant adverse effects
on attentional function in adolescents.