There are actually several meanings of abandonment that can give rise to dream images.
The first links with the idea of being able to let go completely – to be without restraint – and links with the dionysian concept of abandoning the serious for fun, entering into a state of ecstasy and achieving an altered state of consciousness.
The second meaning has a more negative connotation and deals with a sense of loss and deprivation. From a spiritual perspective this can arise from the initial separation anxiety that a baby may suffer when it is first born and realizes that it is no longer in the safe environment of the womb.
There can also be a strong sense, as we progress spiritually, of having been abandoned or of having lost something important, perhaps our relationship with the divine. Dreams can often help us to reconnect as we become more conscious of needing to find a safe haven.