The co-occurrence of Borderline Personality Disorder (BPD) and Intellectual Disability (ID) is a sparsely covered area in the literature. This case series looks to describe the common presentations of these two disorders, both commonly presenting with self-harm, impulsivity, and intense anger. Additionally, three treatment courses of individuals with co-occurring ID and BPD will be described, illustrating the commonalities as well as the modifications of BPD treatment for individuals and in adapting ID supports for those with BPD.

Of the 3,028 children, 16% of those without autism or a learning disability had been diagnosed with a psychotic disorder. And, for children who had autism or a learning disability, only 7% of those given antipsychotics had a psychotic disorder.

Looking further at these records, we found that the children with an intellectual disability or autism were more likely to be given an antipsychotic drug. In fact, 2.8% of the children with an intellectual disability had been prescribed antipsychotics, and 75% of these had autism. By contrast, 0.15% of those without an intellectual disability had been prescribed the medication.

There is little information concerning the prevalence of individuals with intellectual disability (ID) and co-occurring Borderline Personality Disorder (BPD). BPD is the “pervasive pattern of instability of interpersonal relationships, self-images, and affects” that can affect 6% of the population in the US. While the prevalence of ID is estimated to be about 1% worldwide, the prevalence of co-occurrence of BPD and ID is not well understood the similarities of some of the presenting symptoms of each of these disorders can cause diagnostic confusion. BPD can present with self-injury as deliberate self-harm, and individuals with ID have higher rates of self-injury than the general population. Symptoms of BPD may be attributed to the individual’s disability rather that to the separate entity of BPD in what is described as ‘diagnostic overshadowing’. In addition to the diagnostic difficulty, some authors advise not diagnosing patients with a stigmatized disorder, i.e., BPD, when they have already been diagnosed with ID.

The Diagnostic Manual for Intellectual Disabilities-2 (DM-ID-2) describes several limitations in diagnosing individuals with ID and personality disorders including “[taking] into account personal characteristics in the context of a normal cultural framework” . This could mean a boisterous airing of grievances needing to be interpreted in the context of the patient’s culture. A helpful question could be “Does the patient’s family of origin see the noted behaviors as aberrant or unusual?” DM-ID-2 also suggests that IDD itself may have features in common with personality disorders including impulsivity and difficulty regulating frustration and emotions, and because many people with ID have a protected upbringing, they may have limited experience with social norms and community skills. The DM-ID-2 also suggests the adaptation of moving the age of diagnosis to 22 rather than the DSM-5’s 18 years of age.

The criteria, otherwise, should be met with a “pervasive pattern of instability of interpersonal relationships, self-image, and affects, and marked impulsivity” and also including five of the nine diagnostic criteria including fears of abandonment, chaotic relationships, unstable self-image, potentially harmful impulsivity, suicidal threats or self-injury, affective instability, persisting feelings of emptiness, anger dysregulation, and stress-induced paranoia . Interpersonal hypersensitivity, while not explicitly one of the diagnostic criteria, is considered an intrinsic component of BPD. Because this disorder can also be considered significantly heritable, with around 50% of variance explained by genetic factors, families can benefit from knowing the disorder is not an individual’s “fault..

Case 1- Too many feelings

Ms. A is a 25-year-old black woman with a history of Mild ID and asthma presented for evaluation to the outpatient psychiatric clinic for self-injury. She had previously been administered the Wechsler Adult Intelligence Scale (WAIS)-IV with a verbal score of 66 and full scale score of 64. Ms. A reports, “When I get too many feelings, I go crazy. When I get too upset, it’s the only thing that makes me feel better is hurting myself. I mean, I know it’s not good for me, and I try to stop, but it just happens.”

Her team brings her in for increased self-harming. Her mother reports, “She’s always seemed so sensitive—like her feelings get hurt even when people don’t mean it”. Ms. A reports the last significant episode of self-injury occurred when her boyfriend broke up with her at workshop. She reports, “He did it on purpose just to make me mad to try to get me fired”. This demonstrates transient stress-related paranoia and anger dysregulation. When asked if she were more sensitive to interactions with others, she agreed that it felt like it was easy to hurt her feelings. She reports that when her habilitation specialist did not say hi to her first thing in the morning, she “knew” that her habilitation specialist was mad at her. As previously noted, individuals with BPD are sensitive to interpersonal rejection which can precipitate dysphoria and suicidality. When screened for idealization and devaluation, she reported that she tends to love her boyfriends and friends when they first meet until she becomes angry at them for some small or large infraction. She reports that they are then “dead to her.” She reports that she feels that her mood is overly reactive to her environment, the criterion for affective instability, and that she worries about people leaving her despite having had a stable upbringing and reliable home providers. She reports sometimes she “acts up” just because she knows they’ll leave, which is a common manifestation of the fear of abandonment. When screened for impulsive behaviors, her team reports that while she has not had risky sexual behaviors, she has received reprimands at workshop for “making out under the stairs” with two of her last three boyfriends. The team also notes that she will eat anything that is left out, even to the point of making herself sick. The criterion for identity was not able to be elicited as the concept was likely more abstract than could successfully be explained. She did not report dissociative episodes.

Ms. A was diagnosed with Borderline Personality Disorder in accordance with Good Psychiatric Management of Borderline Personality Disorder, by going through each criterion with the team and with Ms. A  She and her team were offered psychoeducation about the diagnosis, typical course of the disease including remission in 85% in 10 years, and that the symptoms are significantly heritable . They were relieved and voiced appreciation for the diagnosis.

Treatment: She began individual sessions 2-4 times a month with her mental health counselor. She was started on low dose lamotrigine, which was titrated slowly to an effective dose of 100 mg/day. At 6 months, Ms. A reported a significant decrease in self-injury and was better able to implement the copings skills that she and her therapist had devised together. At 3 year followup, Ms. A reports affective instability, anger dysregulation, and overeating but reports that she feels much better. Her self-injury was reduced to 2-3 times a year and under unusually stressful circumstances.