Fawzi et al. [25] found that the change in total energy and BMI during Ramadan fasting were significant and independent variables associated with the increase in serum BDNF levels by 44%; however, they could not demonstrate any benefits in schizophrenia patients as a lower BDNF level may worsen the psychiatric status, such as a relapse of bipolar disorder. Here, BDNF is linked to bipolar disorder.