People with personality disorders tend to exhibit problems with impulse control. These problems can manifest as either over-controlled or under-controlled impulses. (Under-controlled impulse control is commonly called a "lack of impulse control". In the same manner that people with personality disorders may have problems with over- or under-controlled affective (emotional) regulation, they also tend to have problems regulating their impulses. Here, too, we can think of impulse regulation along a continuum ranging from over-control to under-control, with healthy personalities falling somewhere in the middle between these two extreme poles.
Consider the issue of self-control and the need for a healthy balance between overcontrol and under-control. On the one hand, we need to control our impulses and to consider the consequences of acting upon an impulse. Having considered the consequences, we then decide how to act accordingly. We determine whether to allow ourselves to indulge the impulse, or whether to inhibit it. The inhibition of certain impulses enables us to behave in ways that are both responsible and socially acceptable. Therefore, in some circumstances the inhibition of our impulses serves to promote our success in both relationships and in the workplace. Two areas of particular concern are aggressive and sexual impulses. If we were to act on our every aggressive or sexual impulse, we would easily get ourselves into a great deal of trouble. On the other hand, the over-control of impulses leads to its own set of problems. A certain amount of carefully considered risk-taking is necessary to reap the benefits of creative expression, rewarding relationships, and successful problem-solving. Some amount of risk-taking is part of the excitement, fun, and spontaneity associated with an enjoyable life. With too much impulse control, we end up feeling restricted, bored, and dull; with too little we can get ourselves into a great deal of trouble. Clearly, a balance between these two extreme poles of over- and under-control would represent a healthy personality.
The challenge to strike the right balance of impulse control affects everyone from time-to-time, including people with healthy personalities. We all have had occasions where we behaved irresponsibly, or unwisely chose to act upon an impulse. At other times, we may have been too controlled, failing to take a risk that would have ultimately benefitted us. Once again, flexibility enables healthy personalities to achieve the proper balance of impulse control most of the time. People with personality disorders are distinguished by the rigidity of their pattern of over- or under-control, and the severity and persistence of their impulse control problems. Rigid and persistent over-control of impulse can manifest itself as inhibition, reluctance to do anything that involves any type of uncertainty or risk, reluctance to start new things or try new activities, and over-conscientiousness or scrupulousness. Rigid and persistent under-control can manifest itself as recklessness and a disregard for rights and needs of other people. This pattern can lead to troublesome or dangerous problems such as drug use, dangerous or risky sexual liaisons, over-spending, assault, or self-injury.
Examples of personality disorders with impulse control problems
Now let's look at some examples of specific personality disorders to illustrate these problems of over- or under-control of impulses.
On the over-controlled side of the continuum is the Avoidant Personality Disorder. People with this disorder are afraid to try new things for fear of embarrassment, and fear of ridicule. They hold back when they are with other people and can come across as stiff and constricted. They lack spontaneity as every action must be considered for its potential to result in embarrassment or ridicule. Subsequently, people with this disorder end up missing out on some of life's unplanned but enriching adventures. Similarly, people with Obsessive-Compulsive Personality Disorder also tend to over-control their impulses. Overly worried about rules and regulations, they can be very scrupulous, and tend to be excessively focused on conscientiousness, morals, and ethics. Preoccupied with lists, and a rigid sense of right and wrong, they rivet their attention toward the smallest details and become unable to complete a task; i.e., they become so distracted by so many small details that they can't see the forest for the trees.
On the other side of the continuum are problems with under-control, or more commonly stated, a lack of impulse control. This lack of impulse control can manifest itself as failure to plan ahead or to think about the long-term consequences. Lack of impulse control is evidenced by such things as impulsive spending; risky sexual behavior; combative and assaultive behaviors; substance abuse; recklessness and excessive risk-taking; gambling; and binge eating. The Antisocial Personality Disorder provides a prime example of these problems with impulse control. Persons with this disorder don't really plan ahead and this type of reckless disregard can cause them to engage in risky behavior merely because it feels good in that one moment. They do not consider the consequences of their behavior, nor its effect on other people or themselves. This is how they end up breaking the law, getting themselves into trouble, and hurting others.
People with Borderline Personality Disorder can have similar problems. As mentioned previously, for someone with Borderline Personality Disorder, the inability to regulate their intense emotions when coupled with poor impulse control can lead to dire consequences. An emotion can become so intense that it becomes very difficult to avoid acting upon the immediate impulse or the urge to do something. Powerful negative emotions such as anger, coupled with a lack of impulse control, will often have disastrous results such as assault or self-injury. Some impulsive behaviors such as alcohol or other drug use, risky sex, and binge eating can also function as coping mechanisms for people with Borderline Personality Disorder. These behaviors may represent ineffective attempts to cope with intense and difficult emotions. These behaviors are dysfunctional because while the behavior may enable the person feel relieved and better in the moment, it ultimately has harmful long-term consequences.
As we have emphasized throughout, these first three core features of personality disorders 1) problems with disordered thinking, 2) problems with affective regulation (feeling), and 3) problems with impulse control (behavior) all have a profound and negative impact upon interpersonal relationships. As a result, the fourth core feature of personality disorders, which we are about to discuss, is considered the most significant and defining feature of all personality disorders.