Chandra Grahan or Lunar Eclipse Dosha is a situation when the Moon is in a birth chart with Rahu or Ketu. As a matter of fact, Rahu and Ketu orbit around the sun in the opposite direction. In addition, they stay on each planet for 18 months and in a house depending on their ascendant. As they move, there might come a time when Chandra or moon will be in the same house as Rahu/ Ketu. This situation is called Chandra Dosha. If this Dosha occurs at the time of the birth of a baby, then the child will have a birth chart with the Chandra Dosha.In fact, the instable planets, Rahu and Ketu will disorganise the effects of the moon. The moon controls the mind. It is the ruler of the mind. Under the effect of Rahu/ Ketu, the moon will lose control of the mind, hence leading to mental disorders.