Asklemmy

The caregiver or partner then continues to present the person as being sick or injured, convincing others of the condition/s and their own suffering as the caregiver.

The causes of FDIA are generally unknown, yet it is believed among physicians and mental health professionals that the disorder is associated with the ‘caregiver’ having experienced traumatic events during childhood

The primary motive is believed to be to gain significant attention and sympathy, often with an underlying need to lie and a desire to manipulate others

Drag isn't especially familiar with MBP, but this is what Wikipedia says in the introduction. That the caregiver is convinced that they're suffering and that they need attention and sympathy. Those are the actions of someone who's in pain, and a link to trauma makes it all make sense.

But yes, the fact that medicine is for helping patients is controversial in the psychiatric community. There's considerable debate on the subject. But the guy who wrote the DSM IV criteria for NPD has stated in multiple interviews that Trump doesn't have NPD, because he isn't suffering.

American psychiatrists have to follow the Goldwater Rule, which says not to speculate on the disorders of public figures. Why? Because that's not what diagnosis is for. Diagnosis is the first step in a plan to treat a patient and help them. Diagnosis should never be about insulting, labelling, or stigmatising a patient in the eyes of others. That's a violation of the Hippocratic Oath.

Number 6 is the only one that’s defined by the treatment of others

All 9 of those criteria only apply if they distress or impair the patient. Also, they're outdated. That's the DSM-IV's criteria. And they've been criticised -

The NPD diagnosis in DSM has been criticized for being one-sided and relying primarily on external socially and interpersonally striking and provocative features.

As such, it has failed to capture the full range of narcissistic personality pathology, especially the internal vulnerability and insecurity characterized by severe self-criticism, insecurity, confusion, shame, aloneness, and fear.

Instead, the diagnosis has primarily emphasized external characteristics related to boasted grandiosity, and obviously adverse interpersonal functioning.

https://www.mind-diagnostics.org/blog/narcissistic-personality/narcissistic-personality-disorder-dsm-5-criteria-and-treatment-options

That's why the DSM 5 criteria have more focus on the individual's impairment and distress:

The essential features of a personality disorder are impairments in personality (self and interpersonal) functioning and pathological personality traits.

To diagnose a narcissistic personality disorder, the following criteria must be met:

A. Significant impairments in personality functioning manifest by:

1. Impairments in self-functioning (a or b):

a. Identity: Excessive reference to others for self-definition and self-esteem regulation; exaggerated self-appraisal may be inflated or deflated, or vacillate between extremes; emotional regulation mirrors fluctuations in self-esteem.

b. Self-direction: Goal-setting is based on gaining approval from others; personal standards are unreasonably high to see oneself as exceptional or too low based on a sense of entitlement, often unaware of their own motivations.

2. Impairments in interpersonal functioning (a or b):

a. Empathy: Impaired ability to recognize or identify with the feelings and needs of others; excessively attuned to reactions of others, but only if perceived as relevant to self; over- or underestimate of own effect on others.

b. Intimacy: Relationships largely superficial and exist to serve self-esteem regulation; mutuality constrained by little genuine interest in others‟ experiences and predominance of a need for personal gain

B. Pathological personality traits in the following domain:

1. Antagonism, characterized by:

a. Grandiosity: Feelings of entitlement, either overt or covert self-centeredness; firmly holding to the belief that one is better than others, condescending toward others.

b. Attention seeking: Excessive attempts to attract and be the focus of the attention of others; admiration seeking.

C. The impairments in personality functioning and the individual’s personality trait expression are relatively stable across time and consistent across situations.

D. The impairments in personality functioning and the individual’s personality trait expression are not better understood as normative for the individual’s developmental stage or socio-cultural environment.

E. The impairments in personality functioning and the individual’s personality trait expression are not solely due to the direct physiological effects (e.g., a drug of abuse, medication) or a general medical condition (e.g., severe head trauma).