The effect of narcissism on relationships is well-documented in psychological literature. Most people in a loving relationship, especially a romantic one, accept a certain amount of give and take between the participants. With narcissists, there is no give; their self-obsession means the entire relationship revolves around them and their wants or needs. People involved with narcissists will typically exhibit symptoms of both physical and psychological stress, or eventually leave them for their own protection. There is treatment for both parties, but the narcissist must exhibit a real commitment to change for it to be effective.
Pathological narcissism is defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM) as a personality disorder in which people have an extreme fixation with themselves. This disorder is found more often in men than women, and affects between 2% and 15% of the overall population. A fragile self-esteem is protected by an inflated sense of one’s own importance, and narcissists are usually convinced that they are always right. They will do anything to get what they want, regardless of how it makes others feel.
Narcissism on relationships that are romantic can be devastating. Usually narcissists will charm their partners at the beginning, but later more insidious traits may emerge. They demand unconditional love on their terms, and will withdraw affection when they are crossed. They may seek out partners who have abandonment issues similar to their own, so that they will not leave them no matter how poor their demeanor. Substance abuse, promiscuity and other self-soothing behaviors can emerge when they feel threatened or bored.
People with this disordered thinking are not usually interested in seeking long-term partners. The effect of their narcissism on relationships results in a focus on short-term pleasure in the form of sexual dalliances, without any real attachment. Commitment is not valuable to them unless it has some sort of self-serving motive. They are restless and always looking for the next encounter. This causes jealousy and anxiety in their partners, who then have to make a decision whether to go or stay.
One of the most visible effects of narcissism on relationships is domestic violence, when narcissists hurt their partners physically or emotionally. Instead of physical harm, some of them use passive-aggressive tactics to undermine their partners’ self-esteem, preventing abandonment and propping up the narcissist's own grandiose vision of self. Because of the narcissist’s abandonment issues, leaving a violent relationship is extremely risky for the abused partner.
Children of narcissistic parents may not get the affirmation they need to develop empathy for others and may end up this way themselves. Conversely, some researchers think the self-esteem movement may be to blame, with its intense focus on exclusively positive reinforcement. Effects of narcissism on relationships can be lifelong, but treatments with psychotherapy, cognitive behavioral therapy and drugs for underlying depression can help. The narcissist must be willing to make a change for therapy to be effective.