Emotionally unstable personality disorder / borderline personality disorder

Emotionally unstable personality disorder (colloquially: borderline personality disorder, hereafter abbreviated to borderline or BPD) is a common misdiagnosis in cases of severe ADHD-C or ADHD-HI.
Semmler attributes this to the fact that the most widely used borderline test, the SKID-II interview, as well as its successor, the SKID-5, ask about the dimensions of emotional instability and impulsivity in a joint construct and therefore mix them inappropriately. The SKID interviews are said to cause frequent misdiagnoses as a result. The IKP (Inventory of Clinical Personality Accentuations) separates these two dimensions and can be re-explored with the Borderline Personality Inventory (BPI) in the case of high scores.¹

• 1. Prevalence of borderline BPD
• 2. Borderline with ADHD
• 3. Differential diagnosis of borderline and ADHD
  • 3.1. Common symptoms of borderline and ADHD
  • 3.2. ADHD symptoms that are atypical for Borderline:
  • 3.3. Symptoms of Borderline that are atypical for ADHD:

1. Prevalence of borderline BPD¶

Borderline prevalence: 0.7 % - 2.7 %², 1 % - 3 %³, 5 %⁴⁵ In psychiatric patients, the prevalence increases to 11 %⁶ to 12 %², in hospitalized patients to 22 %² to 50 %.⁶

75% of people with ADHD are women.

2. Borderline with ADHD¶

ADHD increases the risk of a BPD diagnosis to 33.7%⁷. More on this at Borderline PS / Emotionally unstable PS In the article Psychiatric comorbidities in ADHD.
However, we are seeing a high number of borderline diagnoses that ultimately turn out to be ADHD, which is fully treatable with stimulants. Given the high symptom similarity and the only slowly developing awareness of how far-reaching symptoms and consequences ADHD can have, this is not surprising in our view.

In the case of borderline, in addition to a symptom similarity to ADHD, a comorbid occurrence of ADHD is often found.²⁸⁹ One study addresses the question of whether one of the disorders (ADHD or borderline) can develop into one of the other disorders over time. Apparently, ADHD is more likely to be a preceding Disorder and Borderline is more likely to be a subsequent Disorder in adulthood. The increased number of traumatic childhood experiences in borderline was reported as a significant difference in environmental influences. This, as well as the different genetic disposition described below, argues against a regular developmental sequence between the two disorders. Nevertheless, we are aware of individual cases in which we consider a development from ADHD to a later borderline or a later addition of borderline to be a plausible explanation for the symptom pattern.¹⁰

Since borderline is associated with a genetic disposition on the MAO-A gene, which is also associated with aggression and behavioral disorders, borderline is likely to co-occur primarily with ADHD-HI and barely with ADHD-I.
ADHD resembles a personality disorder in its course (early onset, persistent behavior patterns and possible continuation into adulthood).¹¹
There are those who view ADHD-HI (with hyperactivity) and borderline as a continuum that varies in symptom intensity. One study found that ADHD and borderline are less distinguishable on the basis of individual symptoms, but differ primarily in the intensity of borderline symptoms.¹² Hallowell reports an ADHD-HI type with borderline overtones.¹³ We also see a conspicuous relationship, to the point of strong confusability for laypersons, but assume that the aggressiveness associated with borderline is mediated by genes that are not typical for ADHD. As the correlating gene variants show, ADHD is characterized by a deficit of dopamine and noradrenaline in the dlPFC and striatum, while borderline is characterized by a normal dopamine level in the PFC and an excess of dopamine in the striatum (see below).

3. Differential diagnosis of borderline and ADHD¶

Borderline and ADHD have very similar symptoms, which are easily confused, and a high level of comorbidity. Around 50% of people with ADHD also suffer from borderline ADHD.
The “inner pressure” described in borderline (which can lead to self-harming behavior) is also known in ADHD.

Many adult women with borderline report increased ADHD symptoms in childhood,¹⁴

Differentiation of the symptoms of ADHD and borderline:¹⁵

The previous assumption that ADHD and borderline differ in the time of onset (ADHD earlier, borderline later) is now being questioned.⁹

The BPFSC-11 appears to be good at differentiating borderline and ADHD.¹⁶

3.1. Common symptoms of borderline and ADHD¶

• Impulsiveness^{1718 19 20}
  • Significantly stronger in ADHD-HI/ADHD-C than in Borderline
  • High impulsivity in borderline is thought to indicate ADHD-HI comorbidity.
  • Other view: high aggressive impulsivity an endophenotype of BPD.²¹ We think this is more likely because DAT 9R, the gene suspected in borderline for aggressive-impulsive behavior, is not associated with ADHD. (see below).
  • One study found increased self-reported impulsivity in ADHD and borderline, but increased action impulsivity only in ADHD²²
  • Borderline: Impulsivity only in relation to negative affects, ADHD: Impulsivity also in relation to positive affects²³
  • Borderline: Impulsivity only under stress; ADHD: independent of stress²⁴
  • Addiction problems¹⁸
• Affective lability (ADHD-HI) / affective instability (borderline)¹⁸
  • In persons with ADHD-HI (with hyperactivity) and borderline people with ADHD, behavior and affect regulation are similarly disturbed.
  • Rapid mood swings¹⁷
  • Emotional dysregulation is even more pronounced in borderline than in ADHD. People with ADHD have a better use of adaptive cognitive emotional strategies than borderline sufferers.²⁵ All emotions are perceived considerably more intensely (and with more stressful intensity) than in non-affected persons.⁵
  • Borderline behavioral dysregulation also does not occur in neutral life circumstances, but only in stressful moments.¹⁹
  • Mood swings:
    • Borderline: Anger and aggression, often caused by interactional triggers.²⁶
    • ADHD: can become angry quickly. Anger is almost always short-lived and not regularly directed at interactional triggers. However, the affect can also tip over into hypomania.²⁶
• Attention deficit disorders
  • In ADHD often with too little arousal (lack of activation / stimulation)¹⁸
  • More frequent in BPD with voltage increase as a dissociative phenomenon¹¹
  • Borderline: no attention problems with boring things, ADHD: attention problems especially with boring things²³
• Dissatisfaction
• Dysphoria with inactivity
• Boredom (ADHD-HI) / Dysphoria, boredom, emptiness (borderline)
• Self-esteem issues / offendedness / rejection sensitivity¹⁸
  • Especially Rejection Sensitivity (RS) ⇒ Rejection sensitivity: offendedness / sensitivity to rejection and criticism as a specific ADHD symptom
    • RS has so far been confirmed by most of the people with ADHD we have interviewed
    • Whereby this sickliness is a core symptom in borderline, i.e. much stronger than in ADHD
      • Often extreme jealousy (borderline)
• Excitability, outbursts of anger
• Stress intolerance
  • Stressors lead to considerably higher stress levels in borderline patients, which decrease much more slowly than in those not affected.⁵
• Conflictual relationships (ADHD-HI) / instability in relationships (borderline)¹⁸
• Social weakness, impaired social behavior
• Sleep problems common
  • Borderline often shows a prolonged REM phase and nightmares (on average every 2nd night).²⁷ Nightmares are atypical for ADHD.
  • Difficulty falling asleep, shortened sleep duration, low sleep efficiency with subjectively less restful sleep are common in Borderline,²⁷ as well as in ADHD.
  • Difficulty falling asleep in borderline patients is said to improve well with clonidine.²⁷ Guanfacine could probably also be helpful.
• Inner restlessness, restlessness¹⁷
  • Required voltage reduction
    • For ADHD-HI (more often men): sports, sex¹⁸
    • In BPD (more often women): Dissociation, freezing, self-harm,¹⁸ sex
• Risk behavior
  • BPD: Inner motive: coming out of numbness or self-punishment²⁶
  • ADHD: Inner motive: having fun or relaxation through overstimulation²⁶

3.2. ADHD symptoms that are atypical for Borderline:¶

• Concentration problems¹⁷²⁴
• Attention problems¹⁷²⁴
  • Attention problems with boring things²³
• Distractibility²⁴
• Hyperfocus²⁴
• Motivation problems²⁴
• Cognitive impairments²²
• Hyperactivity²⁴
• Dysphoria with inactivity
• High flow of speech (logorrhea, polyphrasia)¹⁷
• Chasing thoughts, circling thoughts¹⁷
• Disorders of executive functions
  • Disorganization²⁴
• One study found increased self-reported impulsivity in ADHD and borderline, but increased action impulsivity only in ADHD²²
• Slowing of reaction time²⁸ although other studies have also found shorter reaction times in ADHD

3.3. Symptoms of Borderline that are atypical for ADHD:¶

• Self-harming / self-injurious behavior
  Impulsive behavior in response to intense negative feelings (“negative urgency”)²² is one of the most distinctive symptoms that characterize Borderline²⁹
  • E.g. scratching (however, not all self-harming behavior is borderline)
    • Self-injury reduces the very high subjective stress load and objective amygdala activity (by increasing connectivity in frontal-limbic brain regions that dampen amygdala activity) in persons with ADHD after a stress test, while it further increases the (lower) stress load and objective amygdala activity in non-affected persons.⁵
    • Self-injuries that are unintentional or serve more as self-stimulation therefore do not point to borderline, but rather to ADHD
  • Differentiating here: Blay et al.³⁰
• Thinking black and white
  • Shades of gray, both-and, mediating positions are difficult to perceive and hard to bear.
  • In discussions, people with ADHD tend to take extreme positions. For the person with ADHD, this can feel as if they are always slipping off a bar of soap, either falling into one extreme or the other, but not being able to take a middle, both/and or mediating position.
• Identity disorders
• Dissociation
• Unstable self-image¹⁷
• Fear of abandonment¹⁷²⁴
  • Feeling lonely, even when among people.⁵ We suspect that this is much more pronounced in borderline than the feeling of not belonging in ADHD
• Unstable relationships¹⁷²⁴
  • Exaggeration at the beginning²⁴
  • Devaluation at the end²⁴
  • Fear of closeness and fear of abandonment²⁶
  • Often paranoid cognitions at an older age²⁶
  • Often resentful.²⁶
• Suicidal thoughts¹⁷
• Paranoid symptoms¹⁷
• Strong sense of guilt and shame
• Pervasive feeling of inner emptiness²⁴

Comorbid ADHD + Borderline in particular are said to be more pronounced:⁹

• Impulsivity (than with ADHD alone)
• Symptoms of regulation of traits and emotions (as in borderline alone)

In children and adolescents, certain character traits increase the risk of a later borderline personality disorder:⁶

• Affective instability
• Negative affectivity
• Negative emotionality
• Inappropriate anger
• Poor emotional control
• Impulsiveness
• Aggression

People with ADHD differ from those with other personality disorders primarily in their pronounced histrionic and more frequent narcissistic, bipolar/cyclothymic or aggressive characteristics. There is greater instability in relation to anger and anxiety and a greater oscillation in occurrence between depression and anxiety. Surprisingly, the level of intensity of emotion perception is not higher. Obsessive-compulsive, schizoid and anxious-avoidant manifestations, on the other hand, are rarer. These results are independent of gender.³¹

The use of stimulants in borderline personality disorder is controversial.

• On the other hand:
  • Dopaminergic substances (stimulants) can provoke impulsive and aggressive behavior in borderline patients.²¹ This indicates an excess of dopamine in borderline, which differs from the dopamine deficit in ADHD.
    This is consistent with the results of studies according to which borderline correlates with the DAT1 gene variants 9/9 and 9/10, which cause lower DAT expression in the striatum, so that a higher dopamine level in the striatum can be expected due to the lower dopamine degradation caused by DAT.³²
• For this:
  • ADHD treatment with stimulants is also possible in cases of comorbid borderline²³
  • MPH can improve impulsivity in pure borderline (without ADHD)³³

It should be considered that stimulants can reduce impulsivity, hyperactivity and attention problems in the DAT-KO mouse as well as in several other animal models with ADHD symptoms characterized by excessive extracellular dopamine. More on this at ADHD animal models with elevated extracellular dopamine

The 9-repeat variant of the DAT1 gene causes an excess of dopamine in the synaptic cleft because the dopamine transporters then only reabsorb the dopamine insufficiently presynaptically. DAT 9R is associated with affective disorders and borderline personality disorder.³⁴
Borderline correlated more frequently with³²

• DAT1 9/9 (OR = 2.67)
• DAT1 9/10 (OR = 3.67)
• HTR1A G/G (OR = 2.03)

The risk of borderline increases for carriers of the gene variant combinations³²

• DAT1 9/10 and HTR1A G/G (OR = 6.64)
• DAT1 9/9 and HTR1A C/G (OR = 5.42).

ADHD is not associated with DAT1 9R, but with DAT1 10/10, which causes increased DAT expression in the striatum, which is associated with increased dopamine efflux and therefore decreased dopamine levels in the striatum. This now explains why stimulants that increase dopamine and noradrenaline levels in the PFC and striatum work well in ADHD, while they can be counterproductive in borderline.

In contrast, a review reports that DAT1 9R is associated with childhood ADHD and DAT1 10R with adult ADHD³⁵ and that DAT1 9R correlates with increased DAT activity in healthy individuals (meta-analysis, k = 12, n = 511)³⁶.

5 HTTPLR and 5-HT2c are two other candit data genes in Borderline.³⁷

People with ADHD may have more regional μ-opioid receptors in some brain regions and fewer regional μ-opioid receptors in other brain regions. Emotional dysregulation (sadness) is said to correlate with the deviation of μ-opioid receptors compared to non-affected people.³⁸

In BPD, antipsychotics bring about significant but small improvements in cognitive symptoms, mood instability and global functions. The effect on anger/rage is more pronounced. They have no significant effect on behavioral impulsivity, depression and anxiety.³⁹

A study of n = 17,532 patients with BPD found with different forms of treatment:⁴⁰

• the risk of psychiatric rehospitalization
  • increased by
    • Benzodiazepines (HR = 1.38)
    • Antipsychotics (HR = 1.19)
    • Antidepressants (HR = 1.18)
  • unchanged by
    • Mood stabilizers
  • reduced by
    • ADHD medication (HR = 0.88)
    • Clozapine (HR = 0.54)
    • Lisdexamfetamine (HR = 0.79)
    • Bupropion (HR = 0.84)
    • Methylphenidate (HR = 0.90)
• the risk of hospitalization or death
  • increased by
    • Benzodiazepines (HR = 1.37)
    • Antipsychotics (HR = 1.21)
    • Antidepressants (HR = 1.17)
  • unchanged by
    • Mood stabilizers
  • reduced by
  • ADHD medication (HR = 0.86)