Most people who are utilizing defense mechanisms in levels 1-3 are going to have issues with reality testing, which means that they are not able to sort out what is occurring in their own mind versus what is
happening in the external world. Those using pathological defense mechanisms typically have a very low ability to move beyond the perceptual defenses in their head to what is objectively occurring around them. This lack of reality testing makes working with these individuals very difficult (think about trying to convince someone to step off a curb into a street, where the person you are trying to convince only sees a sheer drop off the curb).
The first on our list of pathological defense mechanisms, delusional projection, is a prime example of what happens when individuals lack the ability to do reality testing. A client who is using this defense typically has issues trusting others and in order to cope with their lack of trust in others, they project onto others/the external world, delusions of persecution, e.g., that someone is out to get them. Individuals who use this defense mechanism have very few, if any close social connections, and rarely (at least initially) engage in therapy willingly. Depending on the severity, it can be “treated” with medicine at the far end (if the person is actually suffering from a psychotic break), or through cognitive behavioral therapy at the low end. The CBT treatment would focus on exceptions to the persecution, e.g., when have you trusted people and it has been okay/helpful?
The defense of conversion manifests in psychosomatic issues. The individuals’ inability to deal with intrapsychic issues manifests as physical symptoms (without an actual physiological basis) including at the high-end blindness, deafness, paralysis, or numbness, and at the low-end physical aches and headache (this is particularly true for certain cultures). The goal of therapy is to help the client identify and resolve the underlying psychic conflict at which point the physical symptoms should also resolve.
Denial is probably one of the defense mechanisms that most people are familiar with. In a severe clinical presentation, denial is not just ignoring an issue (e.g., not addressing conflict in a relationship because a person wants to avoid conflict), it is taking it to the extreme where the person actively cannot perceive the issue. This is something that may be seen in individuals with hording behavior; outside observers can see that a house is filthy and unhealthy to live in, whereas the client identifies the living environment as perfectly acceptable.
This can be contrasted or paired with the defense mechanism of distortion, where a person bends the reality to a perceived reality to have their needs met. Using the hoarders again as an example, this person says that each piece of the 30,000 plates s/he has will be used at some point. A rational person knows that 30,000 plates would never be needed, but the person using distortion as a defense mechanism can justify that at some point s/he may need each of those plates, and to not have all 30,000 would leave her/him unprepared. The goal for both denial and distortion is to work with the person on managing the anxiety (which is often the reason for the use of these two defense mechanisms) and help them recognize steps they need to take to get back in touch with reality (and how their world won’t collapse in giving up these defense mechanisms).
Splitting is another defense mechanisms that can very easily lead to psychosis. In the use of the defense mechanism, a person cuts off a part of their psyche that they are unable to accept (in contrast to a self-actualized individual). These individuals view themselves as all good or all bad, and cannot accept that they may have parts of the other side (e.g., Annie is all bad, so when her teacher tells her she did a good job, she cannot be talking about Annie because Annie cannot be good). In its extreme, this defense mechanism can lead to disassociation of parts of self, leading to a fractured or split personality. In therapy, the goal is to help a person reintegrate all the aspects of the self into a unified whole, which includes helping the person recognize that they can do “bad things” without making them a bad person, or that there are parts of the self that others value and are worth valuing.
Extreme projection, separate from delusional projection, is the overt denial of a moral or psychological deficiency. This seems to be frequently seen in politicians (at least in America), where the person denounces something like homosexuality (aspect of self s/he cannot accept) and attacks those who are gay or support gay rights, but in private or intrapsychically is in actuality gay. In therapy the goal is to help this individuals accept the aspects of themselves which they have rejected.
The final two pathological defense mechanisms are superiority and inferiority complexes. In both of these, the individual denies reality by either over or under valuing themselves. The people with a superiority complex, internally, view themselves as insignificant or inferior; to counter this they present a superior front beyond reproach. The people with an inferiority complex views themselves as worthless, and doubts their confidence, even when they have demonstrated competence and others have overtly stated their value. The superiority complex is hard to work with because it involves the person admitting to vulnerability, whereas the inferiority complex involves the person accepting that they are worthy of being valued.