Fear of psychological destruction is the sole motivation for attacking others.
Children have these basic fears of being destroyed and of being abandoned, and the themes in many fairy tales address these fears by showing that it is possible to overcome them (Bettelheim, 1989).
Kohut (1977) and others propose that these fears are basic and remain mostly unmodified in adults who have not fully developed healthy narcissism (we are now coming to understand that the crucial factor here is that some stressful event, early in the development of the areas of the brain attributed to regulating emotions, primitive instincts and defences may have weakened pathways and systems of brain communication allowing an unregulated primitive fear response to impact upon behaviour, perception, interpretation and personality and that narcissistic behaviour is an outpouring of an unregulated non-conscious fear response reacting to a perceived or imagined threat. And that in fact nearly all behavioural and mental disorders share this core breakdown in pathways attributed to regulating primitive instictual impulses due to some form of trauma in early development). They remain in their archaic form as experienced in childhood and provide some of the basis for the exhibited behaviour. Further, there may also be competing fears. The adult may fear psychological destruction will result from intimacy and exhibit behaviours designed to prevent intimate relations from developing. On the other hand, the same person may also fear abandonment, so he or she is jealous. The target of these fears receive conflicting messages and are constantly kept off balance, not knowing what to expect, and left confused by the messages. On some days they are expected to get close and reassure that they will not leave, and at other times they are pushed away or frozen out. Little wonder, then, that these are not usually lasting relationships.
It may be helpful to remember that the destructive narcissist has ready access to their fears of being destroyed and abandoned, which continue to exist in the archaic form experienced in childhood. These fears underlie much of their behaviour, attitudes and feelings and, more important, destructive narcissists usually are not conscious of their fears. For example, these fears can be applied and illustrated to the four categories of narcissists proposed by Burnstein (1986): craving, paranoid, manipulative and phallic.
Narcissists who fall in to the craving category can be described as fearing psychological destruction in their incessant demands. They consider themselves incapable of fulfilling their needs, that is, they are helpless, and they face destruction if their needs aren’t met. The fear of abandonment is seen in their clinging behaviour; they fear they will not be able to continue to exist if the other person abandons them.
Narcissists who fall in to the paranoid category not only are very fearful of their own destructive capabilities but fear that others have the intent of destroying them. Thus, they perceive attacks where none was intended and seek to prevent attacks from others by attacking first or being suspicious and by criticising or blaming others. Fear of abandonment is displayed by jealousy, insistence on knowing everything about the other person, and hypersensitivity to perceived rejection.
Narcissists who fall into the manipulative category fear that if their mask were ever breached or seen through the other person would be so enraged at the impostor that they would then be destroyed, rejected and abandoned. Their lies and deceit are calculated to keep others off guard and at a distance so that they cannot discern the emptiness within.
An updated view of Narcissism can be found here; https://sycofx.wordpress.com/2011/03/24/narcissism-clearing-up-a-few-things/