Melanie Klein describes the earliest stages of infantile psychic life in terms of a successful completion of development through certain positions. A position for Klein describes is a set of psychic functions that correspond to a given phase of development, always appearing during the first year of life, but which are present at all times thereafter and can be reactivated at any time. There are two major positions: the paranoid-schizoid position and the depressive position. The earlier more primitive position is the paranoid-schizoid position and if everything is going well they are going through the depressive position.
The paranoid-schizoid position is conceived as the state of mind of children, from birth to four or six months of age. Although this position develops into the next position, it is normal to move back and forward between the two positions although some people operate in the paranoid schizoid position for much of the time. As one of the originators of Object Relations theory, Klein sees emotions as always related to other people or objects of emotions. Relations during these first months are not to whole objects but only to part objects, such as the breast, the mother's hands, her face etc.
Paranoid refers to the central paranoid anxiety, the fear of invasive malevolence. This is experienced as coming from the outside, but ultimately derives from the projection out of the death instinct. Paranoid anxiety can be understood in terms of anxiety about imminent annihilation and derives from a sense of the destructive or death instinct of the child. In this position before the secure internalistion of a good object to protect the ego, the immature ego deals with its anxiety by splitting off bad feelings and projecting them out. However, this causes paranoia. Schizoid refers to the central defense mechanism: splitting, the vigilant separation of the good object from the bad object.
Klein posited that a healthy development implies that the infant has to split its external world, its objects and itself into two categories: good (i.e., gratifying, loved, loving) and bad (i.e. frustrating, hated, persecutory). This splitting makes it possible to introject and identify with the good. In other words: splitting in this stage is useful because it protects the good from being destroyed by the bad. Later, when the ego has developed sufficiently, the bad can be integrated, and ambivalence and conflict can be tolerated.
Later with greater maturity and the resolution of the depressive position, the ego is able to bring together the good and bad object thereby leading to whole object relations. Achieving this involves mourning the loss of the idealised object, and associated depressive anxieties.
Klein described development as proceeding through two phases: the paranoid-schizoid position and the depressive position. In the paranoid-schizoid position, the main anxiety is paranoia and hypochondria, and the fear is for the self.
When things are going well, the mother is experienced as an all benign figure. However, when needs or desires of the young baby are not immediately met by the mother, because she is not there to fulfill them, the absence of the good object is experienced as the presence of the bad object. The bad object is then hated and in fantasy it is attacked. The hated frustrating object quickly becomes persecutory as it is imagined to get revenge in a similar way to how it is being treated. This is why the baby feels persecuted, hence the "paranoid" in paranoid schizoid.
Over time the baby becomes more able to tolerate frustration and hold onto the good object for increasing periods. Klein emphasizes that the good and bad parts of the self are projected onto or into the object. This represents the operation of the life and death drive, of love and hate.