Bipolar disorder can be stabilized by regulating the levels of norepinephrine and serotonin. Norepinephrine can heighten blood pressure which can lift up a person's emotions. Serotonin can level heightened emotions. These two can are prescribed to people who suffer from bipolar disorder.
speed of light does not change, it has to travel more in a medium than in vacuum, When light is passing through a medium, the electrons in the medium absorbs the energy from the light and gets excited and releases them back.But Light waves are made up of both an electric and magnetic wave, so changing those quantities (permittivity and permeability) will change the measured speed of light.