The effects of L-amphetamine sulfate on cognition in MS patients: results of a randomized controlled trial

Defects in processing speed and memory are common in multiple sclerosis (MS) patients. In other populations, amphetamines have been shown to enhance cognition, but their use is limited by adverse behavioral effects. The L-isomer may have equivalent cognition enhancement with less adverse effects due to decreased potency in subcortical areas. The aim of this study was to assess the safety and efficacy of L-amphetamine sulfate in the treatment of cognitive dysfunction in MS. This was a 2:1 randomized, placebo-controlled, double-blind trial, involving 33 MS clinics across the USA. One hundred and fifty-one clinically definite MS patients with documented cognitive dysfunction who were relapse free for >or=90 days, with an Expanded Disability Status Scale (EDSS)