Advocates of the Buteyko method claim that it can treat a wide range of other diseases and symptoms (numbering up to 150), including diabetes, reproductive disorders and psychological disorders, which they believe is aggravated by hyperventilation and hypocapnia, and therefore are treated by use of the Buteyko method. However, research into the effectiveness of Buteyko have focused almost exclusively on asthma with a small amount of research on sleep apnea. Members of the medical community have been skeptical of the efficacy of Buteyko due to the often "exaggerated and unsubstantiated claims" earlier made by Buteyko practitioners.