One of the most problematic aspects of having a mother with borderline personality disorder is dealing with their emotional volatility. Borderlines seek support and validation from their child, which they could never get from their own parents. Moving in and out of poorly integrated ego states, it’s impossible to know what will trigger them to jump ship from, say, a caregiving persona to its opposite (and regressively childish) care-demanding demeanour. Regrettably, however, it’s mostly a guessing game. Unable to predict which parent will show up next leaves you confused and anxious.

What’s Adaptive in Living with a BPD Parent
In the end, just as the BPD’s genetic endowment and environmental contingencies sabotaged their healthy development, so do their children often sabotage their non-maternal relationships because of how they felt they had to “program” themselves to fit into their own chaotically dysregulated environment.
Here are four areas of juvenile adaptations to BPD parents that cause children to regard themselves adversely and cast a negative spell on their personal and professional relationships later on.

Emotional Instability and Insecurity
Unable to take charge of their emotions, BPD moms could hardly be worse models for their kids. Children learn to gain control of their feelings because they’re taught how by parents who help them appreciate things from a broader, more balanced, and rational perspective.
But maturationally arrested BPDs can’t do this themselves, doubtless because of their own inherited and trauma-generated deficits. Given their non-chosen limitations, BPDs are doing the best they can. They don’t consciously mean to harm their children, yet they’re cursed with enormous blind spots that all too easily can be passed onto their progeny. For example, their uncontrollable mood swings and the indiscriminate intensity of their emotional reactions may be involuntary.

Irresponsibility in Caretaking
As already alluded to, in several ways BPDs unintentionally parentify their children. When they’ve been triggered and regressed to a childhood ego state, they can self-deludedly mistake their child for an adult. Consequently, they’ll insist – with the almost limitless power they hold over their offspring – that the child offer them the validation never received when they were in the custody of their own ignorantly irresponsible parents. Additionally, or alternatively, the child may be assigned parental responsibility for their younger siblings. As a result, such children may struggle in their efforts to evolve a sense of autonomy distinct from this mutually dependent caregiving role.

Inability to Validate Their Child’s Thoughts and Feelings
Desperately needing their child to confirm their perspective, rarely supported by their own parents originally, BPDs have great difficulty validating their child’s emotions and viewpoints when they diverge from their own. And when, therefore, they’re compelled to disconfirm their offspring’s reality, they can be understood as gaslighting their child.
The tragic outcome of their obliviousness is that the child is left afflicted with self-doubt, unable to trust the truth of their personal experience. Moreover, the child – accidentally abandoned emotionally – is left with a distorted sense of reality, reduced confidence and self-esteem, and mistrust in their own judgment. That, in turn, can create irresolvable difficulties in comfortably asserting reasonable boundaries with others. Because their cognitions and emotions go down different paths, their boundaries don’t feel reasonable.

Modeling Dysfunctional Methods of Coping with Stress
As much as kids learn to cope with adversity through observing how their dominant parent has handled disappointments and failures, they’re also highly subject to developing mental disorders aligned to their caretakers. Susceptible to complex PTSD, as transferred to them through the emotional turmoil prevalent in their homes, they can grow into individuals plagued by such dysphoric states as guilt, shame, anxiety, or depressive disorders; eating and other functional disturbances – and (hardly surprising) impulsiveness, aggression, obstinacy, and (alas) full-blown BPD.
Their mother’s primitive, dysregulated coping devices may well become their own. Inevitably, just as was true earlier for their unresilient mother, they’ll wind up unconsciously manifesting retaliatory behaviours almost guaranteed to jeopardise their later attachments.

The Solution to This Enduring Dilemma Is Complicated
Seldom is there any simple solution for the widespread problems experienced by children of borderlines. If they can, non-defensively and protractedly, engage with a highly proficient therapist and receive what might best be designated “corrective re-parenting”, they may finally be able to cultivate healthier beliefs, attitudes, and communication skills untenable in their youth. Beyond that, establishing warm, supportive, and understanding relationships – from friends in whom they can safely confide – can significantly advance positive change. That is, with a liberating growth mindset, they can grasp more fully what happened to them in childhood and begin to revise residual feelings of distrust and hyper-vigilance. Support groups, too, can be valuable in helping them alter the no-longer-adaptive programming so deeply ingrained in the past.