The authors relate the results of studying intellectual work fitness in patients with anorexia nervosa (in the stage of cachexia) receiving the vitamin-like drugs carnitine and cobamamide. It has been shown that the long-term food deprivation leads to a reduction of intellectual work fitness, lability of productivity, fluctuations in the work quality, appearance of latent fatigue. In spite of the fact that standard nonspecific treatment ameliorates intellectual work fitness, it does not lead to its normalization. The use of carnitine and cobamamide in the course of nonspecific treatment results in the reduction of the time spent on task implementation, a rise of the work rate as compared to the control group. However, this does not fully remove latent fatigue and does not bring about complete recovery to normal of intellectual work fitness. The combined use of carnitine and cobamamide eliminates fluctuations in the work rate and normalizes the scope and productivity of intellectual work.