When moon is alone in a house and if there is no planets on either side of the house, the yoga is a kemdrum yoga. For example: When moon is in 4th house and there are no other planets on third and fifth house, it forms a Kemdrum yoga.
Interpretation of Kemdrum yoga
With time, there are other definitions of kemdrum yoga besides the above one which is basically the original one. However, below are the other definitions of Kemdrum yoga.
If moon is with Rahu and Ketu and there are no planets on either side of moon, then also it forms Kemdrum yoga.
There is also a belief that if Moon is aspected by any planet, it cancels the kemdrum yoga. However, it not the case.
Why moon needs planets on either side
As moon is a soft planet and it represents mind, planets on either side of moon gives strength to moon. Planets around moon can easily influence moon. So moon can rely on the planets surrounding it and can have thoughts related to the planets.
When moon is alone, it cannot rely on any planet and such type of native are basically loners. They feel less connected with people around. However, analysis of the entire horoscope is must before conclusion.
However, dignity of moon is always important. If moon is in friendly , own or exalted sign, it may not give much trouble even if the yoga is present. The yoga can be challenging when moon is debilitated or in enemy sign.
Meditation can be a great help for people with this yoga. It balances the mind and helps moon to remain stable.