Chitta is an envelope of subtle energies which surrounds the head and permeates the brain. The astral body is the emotional body; the chitta is the mental body. They are both intimately linked and operate together.
Ching is sexual energy and is a synthesis of the chi produced in the various glands and organs throughout the body (the etheric/chi body). Chitta is similar to ching as it is a synthesis of the various astral forces which make up the astral body. It is also a synthesis of the chi energies and ching. The brain is fed by the chi from the various organs and glands as well as ching (sexual energy). A very subtle envelope of chi is created through this process which is able to interact with the physical brain as well as the astral forces. The astral body interacts with this envelope of refined chi and as a baby grows up the structure of Astral Substance in this area grows more and more complex. When the baby is young the chitta is basically this refined chi and has not been filled with Astral Substance. At this time the higher light of the baby is reflected through the chitta and so the consciousness is very clear. The Astral Substances have not yet crystallized in the chitta so the light shines through.
As the baby grows up and the astral forces are impacting into the etheric body they are also impacting into the chitta (incarnating). As the chitta is such a refined and subtle form of chi the astral forces can interact with it better than the rest of the etheric body. Thought processes become more complex as more Astral Substance becomes a part of it. The Astral Substances begin to mix with the chi layer of the chitta, creating a synthesis of chi and astrality. Each belief or piece of knowledge the baby gathers is formed in the chitta as astral crystallizations. The more complex the structure formed by these crystallizations, the more complex the thought processes become. So eventually the chitta becomes a very subtle and refined but very complex structure of astral and chi energies. The more complex the structure the more it will block the light of the Higher Self just like the crystallized astral body. If the belief patterns formed are true and in line with the truth of the Higher Self the structure will not be as solid and so the light will not be blocked as much. False beliefs however, whether they are about yourself, others or the World around you need to be more solid. Because your higher light is sending the truth to you at all times, a false belief will require a more solid crystallization in the chitta. If the chitta is full of false beliefs it will block the higher light more.
The structure in the chitta is just like that of the astral body and can also be seen as being made up of Samskaras. The difference is that the Samskaras in the astral body are caused by intense emotions and tend to be much larger. As the chitta is such a refined substance, Samskaras can be created very easily and are much smaller. Large emotional Samskaras are also created in the chitta and these ones will again form a foundation of personality just like the astral bodies Samskaras. The two bodies interact with each other and any large Samskara in the astral body will be accompanied by a group of smaller ones in the chitta. The repression of the intense emotions in the astral body is helped along by the chitta and its increased structure. This structure can be very complicated and its purpose is to keep emotional pain under the surface.
The increased structure in the chitta and its repression of emotions in the astral body lead to a state of being stuck in your head. The thoughts will not stop and you have no control of them.
The chitta depends on ching for its health and optimum functioning. There is an intimate link between sexual energy and the chitta. When puberty is reached we begin to lose sexual energy and so the chitta loses a large part of its nutrition. When girls begin menstruation and boys begin to ejaculate, a large amount of ching is lost. If this loss did not occur there would be far more energy for the chitta and it would be much healthier. When sexual energy is lost, the chitta will actually give some of its energy to the making of new ching which is used in the production of sperm and eggs. If this is then lost through further ejaculation or menstruation, the chitta will again give energy. If this loss of sexual energy is stopped through the proper tantric techniques, the chitta will instead be fed by the ching and will not have to give itself to produce more sexual energy. The cycle of loss is turned into enormous amounts of energy for the chitta which in turn will make the brain far healthier. The consequences of this interaction should not be overlooked, especially if you are on a spiritual path.