In RCTs with a treatment duration of 4 weeks or more, however, no positive effect could be demonstrated on cognitive functioning with modafinil and armodafinil addition. Yet, four single-dose crossover RCTs of modafinil addition show significant positive effects on executive functioning, verbal memory span, visual memory, working memory, spatial planning, slowing in latency, impulse control and recognition of faces expressing sadness and sadness misattribution in the context of disgust recognition. The addition of modafinil or armodafinil to an antipsychotic regime, despite theoretical and preclinical considerations, has not been proved to enhance cognitive function, attenuate fatigue, enhance activity, improve negative symptoms and reduce weight in patients with schizophrenia.