Mental and psychiatric disorders

Author: Ulrich Brennecke
Review 08/2024: Dipl.-Psych. Waldemar Zdero

• 2.5.1. Anxiety disorders (annual prevalence: 22.9% (women), 9.7% (men))
  • 2.5.1.1. Panic disorder (3.2 to 3.6 %)
  • 2.5.1.2. Generalized anxiety disorder (1.9 to 31.1 %)
• 2.5.2. Excretory disorders (enuresis, defecation) (children: 18.5 %)
• 2.5.3. Affective disorders (10 to 17 %)
  • 2.5.3.1. Depression (10 % (men) 20 % (women))
  • 2.5.3.2. Bipolar Disorder (annual prevalence: 3.1 % (women), 2.8 % (men))
    • 2.5.3.2.1. Depressive episode of bipolar Disorder
    • 2.5.3.2.2. Manic episode of bipolar Disorder
  • 2.5.3.3. Cyclothymia (13 %)
• 2.5.4. Circumscribed developmental disorders (partial performance disorders) according to ICD-10 (approx. 10 to 15 % (?))
  • 2.5.4.1. Dyspraxia (5 to 6 %)
    • 2.5.4.1.1. Motor dyspraxia / circumscribed developmental disorder of motor functions (UEMF)
    • 2.5.4.1.2. Ideomotor dyspraxia
    • 2.5.4.1.3. Ideational dyspraxia
    • 2.5.4.1.4. Verbal dyspraxia
  • 2.5.4.2. Developmental coordination disorders
  • 2.5.4.3. Partial performance disorders
    • 2.5.4.2.1. Reading and spelling disorder (dyslexia) (5 %)
    • 2.5.4.2.2. Calculation disorder (dyscalculia) (5%)
• 2.5.5. Post-traumatic stress disorder (PTSD) (5 % (men), 10 % (women))
• 2.5.6. Tic disorders, Tourette syndrome (1 % to 15 %)
• 2.5.7. Internet addiction (3.9 %)
• 2.5.8. Disorder of social behavior / Conduct Disorder (1.5 % to 5 %)
• 2.5.9. Emotionally unstable personality disorder / borderline personality disorder (1 - 5 % (women), 1 % (men))
• 2.5.10. Obsessive-compulsive disorder (1 to 3 %)
• 2.5.11. Antisocial personality disorder (0.2 - 3 %)
• 2.5.12. Narcissism (0.5 to 2.5 %)
• 2.5.13. Schizophrenic Disorder (1 %)
• 2.5.14. Psychoses (1 %)
• 2.5.15. Autism spectrum disorder (ASD) (0.9 %)
• 2.5.16. Fragile X syndrome (0.22% (men) to 0.66% (women))
• 2.5.17. Pervasive developmental disorders (PDD) (0.06 %)
• 2.5.18. Wilson Disease (0.0033 %)
• 2.5.19. Monoamine neurotransmitter disorders
  • 2.5.19.1. Genetically caused BH4 disorders (approx. 0.0002 %)
  • 2.5.19.2. Missing or greatly reduced DAT
• 2.5.20. Predominantly milieu-related behavioral problems
• 2.5.21. Oppositional defiant behavior (ODD)
• 2.5.22. Auditory processing and perception disorder (AVWS)

2.5.1. Anxiety disorders (annual prevalence: 22.9% (women), 9.7% (men))¶

Prevalence: 22.9% of all women, 9.7% of all men within one year.¹²
Prevalence in girls under 18: 7.85%.³
Anxiety disorders are comorbid in 25% of people with ADHD,⁴ 16.7% of children with ADHD and 27.2% of adults with ADHD.⁵ Other sources cite 15% to 35%⁶ and 35.6% of adults in England in 2007.⁷

Performance anxiety is particularly common.⁸

Common symptoms of anxiety disorders and ADHD:⁹

• Inner restlessness
• Concentration problems
• Attention reduced
• Mood swings
• Sleep problems

ADHD symptoms that are atypical for anxiety disorders:

• High flow of speech (logorrhea, polyphrasia)
• Chasing thoughts, circling thoughts
• Impulsivity (atypical for ADHD-I)
• Impaired executive functions¹⁰

Symptoms of anxiety disorders that are atypical of ADHD:

• Fatigue
• Muscle tension

Anxiety in ADHD may partially reduce impulsivity and response inhibition deficits, exacerbate working memory deficits, and appear to be qualitatively different from pure anxiety. Comorbid anxiety in ADHD appears to have divergent forms of expression:⁶¹¹

• Seem increased
  • Negative affect
  • Mood disorders
  • Disruptive social behavior
  • Attention problems
  • School phobia
• Seem reduced
  • Anxious / phobic behavior
  • Social competence

2.5.1.1. Panic disorder (3.2 to 3.6 %)¶

Prevalence of panic disorder: 3.2% to 3.6%¹²

2.5.1.2. Generalized anxiety disorder (1.9 to 31.1 %)¶

Prevalence of generalized anxiety disorder: 1.9% to 31.1%¹²

2.5.2. Excretory disorders (enuresis, defecation) (children: 18.5 %)¶

18.5% of children with ADHD are affected.⁵

2.5.3. Affective disorders (10 to 17 %)¶

Prevalence:
Lifetime: 10 % to 17 %¹³
under the age of 18: Girls 2.54 %, boys 1.10 %.¹⁴

Affective disorders are described in 27.9% of children with ADHD and in 57.9% of adults with ADHD⁵. Furthermore, a prevalence of 37.1 % for mood instability and 29.9 % for depression in adults in England in 2007 is cited.¹⁵

2.5.3.1. Depression (10 % (men) 20 % (women))¶

Depression must be distinguished from mere dysphoria during inactivity, which is a typical symptom of ADHD and does not constitute depression. Treatment with antidepressants would be inappropriate here.
For more details, visit ⇒ Depression and dysphoria in ADHD In this chapter.

12% to 50% of children with ADHD also suffer from depression, which is five times more common than in children without ADHD.⁶ A study of young adult persons with ADHD reported a lifetime prevalence of ADHD of 25.9%,¹⁶ which is also around five times higher.
The lifetime prevalence of major depression is 15%¹⁷; women are affected twice as often as men, i.e. women 20%, men 10%.

In children with ADHD, emotional dysregulation occurs before comorbid depression.¹⁸¹⁹ This is not surprising, as emotional dysregulation is an original ADHD symptom, while depression can occur as a comorbid Disorder. Nevertheless, the degree of emotional dysregulation in children with ADHD appears to moderate the likelihood of later depression.²⁰

Common symptoms of depression and ADHD:⁹

• Inner restlessness (typical in atypical depression, less so in melancholic depression)
• Concentration problems
• Attention problems²¹
• Memory problems²¹
• Sleep problems
• Daytime sleepiness (typical in atypical depression, atypical in melancholic depression, possible in ADHD)
• Negative self-image⁸

ADHD symptoms that are atypical for depression:

• Rapid mood swings
• Dysphoria only during inactivity
• High flow of speech (logorrhea, polyphrasia)
• Chasing thoughts, circling thoughts
• Impulsivity (atypical for ADHD-I, atypical for melancholic depression)
• Problems with cognitive control²²

Symptoms of depression that are atypical for ADHD:

• Permanent depressive mood (even with things that are actually interesting)
• Low mood in the morning (melancholic depression)
• Low mood in the evening (atypical depression)
• Weight loss (in ADHD at most as a side effect of stimulants)
• Reduced interest in activities (in the case of ADHD rather withdrawal due to increased sensitivity or social phobia)
• Suicidal thoughts
• Low desire for rewards²²

In persons with ADHD, depression typically occurs years after the onset of ADHD symptoms.²³ In this case, it is essential to treat the underlying ADHD, which is often the cause of the depression, in addition to the existing depression. Otherwise, the depression would merely be treating a secondary symptom of ADHD.²⁴²³¹¹
Around 34% of all treatment-resistant depression is caused by previously unrecognized ADHD.

2.5.3.2. Bipolar Disorder (annual prevalence: 3.1 % (women), 2.8 % (men))¶

Prevalence: 3.1 % of all women, 2.8 % of all men within one year¹

Bipolar Disorder is characterized in particular by an alternation between depressive and manic symptoms. The changes can occur at different speeds. There is not always a change to a full-blown manic episode.

ADHD occurs more frequently than average in people with ADHD, but the comorbidity with ADHD is probably weaker than with other mental disorders.⁶ The prevalence of ADHD in people with ADHD differs according to the age at which the bipolar disorder first occurs²⁵

• Childhood: 80 to 95% have comorbid ADHD
• Youth: approx. 50 % have comorbid ADHD
• Adulthood: approx. 25 % have comorbid ADHD

In a reaction test study, both persons with ADHD and bipolar showed significantly increased variability of infrequent slow reactions compared to controls, while bipolar people showed significantly increased speed and variability of typical reactions in the flanker task compared to persons with ADHD and controls.²⁶

2.5.3.2.1. Depressive episode of bipolar Disorder¶

The common and different symptoms of depressive episode of bipolar Disorder and ADHD correspond to those of depression and ADHD.

See above under depression and at ⇒ Depression and dysphoria in ADHD In the section⇒ Detailed description of individual ADHD symptoms in the chapter*⇒ Symptoms.*

2.5.3.2.2. Manic episode of bipolar Disorder¶

Common symptoms of manic episode of bipolar Disorder and ADHD:

• Concentration problems⁹
• Attention problems²¹⁹
• Memory problems²¹⁹
• Sleep problems⁹
• Daytime sleepiness (typical in atypical depression, atypical in melancholic depression, possible in ADHD)⁹
• Rapid mood swings^{27 9}
• Chasing thoughts, circling thoughts^{27 9}
• Impulsivity (atypical for ADHD-I)²⁷⁹
• Problems relaxing (ADHD-HI, bipolar in manic phase)²⁷
• Regulation of own arousal, inner restlessness, restlessness²⁷
• Hypersexuality²⁵

ADHD symptoms that are atypical for manic episodes:

• Dysphoria only during inactivity

Symptoms of bipolar that are atypical of ADHD:

• Alternation between depressive and manic phases

In ADHD, mood swings tend to be triggered (reactive) and disappear quickly when distracted, whereas bipolar manic phases tend to be more continuous and longer lasting.²⁸

2.5.3.3. Cyclothymia (13 %)¶

Cyclothymia (cyclothymia) is a chronic rapid change in mood and drive without reaching the intensity of the symptoms of Bipolar Disorder. Hypomanic and depressive phases alternate. Cyclothymia has a prevalence of 13% in the general population.

Cyclothymia has been found in 75% of all people with ADHD and is significantly increased in ADHD and depression.²⁹

2.5.4. Circumscribed developmental disorders (partial performance disorders) according to ICD-10 (approx. 10 to 15 % (?))¶

Partial performance disorders are said to be a common comorbidity (especially in the ADHD-I subtype without hyperactivity).
Dyspraxia, on the other hand, is a purely motor development disorder that tends to be confused with ADHD-HI (without inattention).

2.5.4.1. Dyspraxia (5 to 6 %)¶

Prevalence 5 to 6 %³⁰³¹

Dyspraxia is also known as “clumsy child syndrome” or “clumsy child syndrome”.
Dyspraxia is a developmental disorder that lasts a lifetime.
Dyspraxia is very often comorbid with ADHD or ASD.
Children with dyspraxia show no deviations in intelligence.

There are different forms of dyspraxia.

2.5.4.1.1. Motor dyspraxia / circumscribed developmental disorder of motor functions (UEMF)¶

Problems with:

• Motor deceleration
• Balance problems
  • Impaired gait
  • Difficulty getting dressed while standing
• Clumsiness in complex movements that require balance and dexterity³²
  • Catch ball
  • Bounce
  • Jump
  • Climb
  • Cycling
  • Swim
  • Couple dance
• Impaired automation of fine motor and gross motor activities
  • Impaired handwriting
    • Difficulty guiding the pen with the correct pressure
    • Problems adhering to the boundaries of the sheet.
    • Writing on the computer is much better
  • Problems tying shoelaces or bows
  • Problems closing buttons
  • Difficulty eating with a knife and fork
  • Problems cutting out a figure cleanly
  • Frequent dropping of things
  • Problems with careful handling of glasses or crockery
  • Difficulties when pouring into glasses
  • Problems with crafting or wrapping gifts
• Difficulty in acquiring new motor skills
• Impaired eye-hand coordination
• Frequent confusion between right and left
• Problems with the Order of priority when putting on clothes
• Rapid fatigue during physical activity
  • Sports
  • Hiking
  • Physically active play
• Easily distracted during tasks
  • Too much information on one sheet confuses
  • Improved task performance with larger line spacing, larger font

No problems with:

• Hyperactivity.

2.5.4.1.2. Ideomotor dyspraxia¶

Problems with:³³

• Execution of your own action plan
• Complete actions in full
• Writing difficulties
• Action difficulties
• Execution of understood instructions impaired
• Order of priority is easily mixed up
• Impairment of imaginative or creative play

No problems with:

• Describe movement sequences
• Recognize the mistakes of others
• Read
• Talk

2.5.4.1.3. Ideational dyspraxia¶

Difficulties in planning and describing motor actions, but they have no motor impairment.³³

Problems with:

• Forming series (associated with memory loss)
• Describe sequences of actions
• Read words
• Work quickly
• Keep order

No problems with:

• Imitate individual movement sequences
• Write words

2.5.4.1.4. Verbal dyspraxia¶

Approximately 30% of children with dyspraxia also have a verbal developmental delay = verbal dyspraxia.³⁴

Verbal dyspraxia is a disorder of speech motor planning. The speech organs are not impaired (tongue, vocal cords).

• Problems with planning speech movements
• Difficulty pronouncing the right words at the right time in the right Order of priority.
• Frequent coughing or choking when eating
  • Sequence of sucking, swallowing and breathing made more difficult
  • High saliva production when switching from porridge to solid meals
• Language development significantly delayed
  • Significantly later start to speak
  • Only a few “babbling sounds” at the beginning
  • Later often vowel language without consonants (“Oaaaa”, “Eeea”).
• Often also problems with gross motor skills (see motor dyspraxia)
  • Stumble
  • Bump into each other, lots of bruises
  • Learning difficulties
    • Read
    • Spell

The risk factors for the development of dyspraxia are still unclear. As with ADHD, environmental influences during pregnancy and birth appear to increase the risk.

2.5.4.2. Developmental coordination disorders¶

The extent to which the concept of developmental coordination disorders differs from that of circumscribed developmental disorders of motor functions and developmental coordination disorder (DCD) is unclear.

There are said to be different subtypes with six main symptom groups:

1. general instability / slight tremor
2. reduced muscle tone
3. increased muscle tone
4. Inability to perform a smooth movement or to combine individual movement elements into an overall movement
5. Inability to form written symbols
6. Difficulties with visual perception associated with the development of the eye muscles

People with ADHD are said to have ADHD in 50% of cases.

The risk of ADHD is also increased in children aged 4 to 5 years with developmental coordination disorder.³⁵ However, the DSM-5 scale appears to be less effective here.³⁶

2.5.4.3. Partial performance disorders¶

The comorbidity of ADHD and learning disorders is reported to be between 10% and 90%.⁶
Learning disorders are said to correlate more frequently with ADHD-I than with ADHD-HI.³⁷ Writing disorders are said to be twice as common as reading, arithmetic or spelling disorders in persons with ADHD.³⁸

2.5.4.2.1. Reading and spelling disorder (dyslexia) (5 %)¶

While dyslexia is a genetically caused disorder, a reading disability is an acquired disorder and easier to improve through practice.
Dyslexia in 17.6% of children with ADHD before⁵ and is said to be more common in ADHD-I than in ADHD-HI.³⁹
Analyses of neuropsychological measures suggest that a co-occurrence of dyslexia and ADHD may be at least partly due to weaknesses in cognitive processing speed and working memory. In a psychoeducational assessment of reading difficulties, attention should always be paid to ADHD and other emotional and behavioral difficulties.⁴⁰
Cognitive profiles are better predictors of literacy achievement than diagnostic outcomes in children with severe ADHD symptoms.⁴¹

2.5.4.2.2. Calculation disorder (dyscalculia) (5%)¶

Dyscalculia is a genetically caused disorder, while dyscalculia is an acquired disorder and is easier to improve by practicing.
Dyscalculia is said to occur more frequently in ADHD-I than in ADHD-HI.³⁹

2.5.5. Post-traumatic stress disorder (PTSD) (5 % (men), 10 % (women))¶

Prevalence: 10% of all adult women and 5% of all adult men suffer from post-traumatic stress disorder.⁴²⁴³
60% of all men and 50% of all women have at least one potentially traumatizing experience in their lives.⁴⁴
Of these suffer from PTSD:

• Rape victims: 49 %⁴⁵
• Severe beatings or physical assaults: 31.9 %⁴⁵
• Victims of crime: 25 %⁴⁵
• Sexual assault without rape: 23.7%⁴⁵
• Serious accident (car or train): 16,8 %⁴⁵
• Shooting or stabbing: 15.4 %⁴⁵
• Sudden death of a close relative or loved one: 14.3 %⁴⁵
• Childhood life-threatening illness: 10.9%⁴⁵
• Victims of potentially traumatic experiences without crime: 9.4 %⁴⁵
• Witnesses of a murder or violent attack: 7.3 %⁴⁵
• Natural disaster: 3.9 %⁴⁵

Sleep problems are common in both ADHD and PTSD. In PTSD, these often arise in the first 2 weeks after the traumatizing event and are often characterized by persistent nightmares,⁴⁶ which is also not typical for ADHD. In ADHD, on the other hand, the sleep disorders usually persist for life.

The Posttraumatic Stress Disorder subscale of the Child Behavior Checklist (PTSD-CBCL) is good at distinguishing PTSD from ADHD.⁴⁷

While ADHD is associated with reduced dopamine and noradrenaline levels, PTSD is thought to be associated with excessive noradrenaline release.⁴⁸ As noradrenaline (like dopamine) acts in the form of an inverted-U curve⁴⁹, this could explain why some people with ADHD do not improve on ADHD medication (which increases dopamine and noradrenaline).

• Relationship behavior:
  • k-PTBS: Often paranoid/mistrustful view of other people. No fear of being abandoned. Possibly conscious decision for a relationship⁵⁰
  • ADHD: no fear of abandonment⁵⁰
• Mood swings:
  • k-PTBS: No fundamental acting out, but chronic depression and permanent tension⁵⁰
  • ADHD: Can become angry quickly. Anger almost always short-lived and not regularly directed at interactional triggers⁵⁰
• Risk behavior:
  • k-PTBS: Dangerous situations are not recognized as such⁵⁰
  • ADHD: Inner motive: having fun or relaxation through overstimulation⁵⁰

Differentiation of the degree of traumatization using the IES-R (Impact of Event Scale - Revised). Example graphic by Semmler.

2.5.6. Tic disorders, Tourette syndrome (1 % to 15 %)¶

Source²

Prevalence: 1% in primary school age (varying degrees of severity), 15% in primary school age (including mild and transient forms).⁵¹
Tic disorders are present in 9.5% of children with ADHD.⁵
31%⁵² to 55%⁵³ of children with tic disorders also show ADHD.

2.5.7. Internet addiction (3.9 %)¶

Prevalence: among students in Germany 3.9% (2019) to 7.8% (2020, corona lockdown year)⁵⁴
Internet addiction was differentiated into two subtypes by one study: one subtype that correlated with impulsivity and ADHD-HI and another subtype that correlated with compulsivity.⁵⁵

2.5.8. Disorder of social behavior / Conduct Disorder (1.5 % to 5 %)¶

Source²

Common symptoms:⁵⁶

• Aggressive behavior
• Lies
• Stealing
• Arson
• Running away from home and school

Conduct Disorder is usually supported by comorbid Disorders. These are common:⁵⁶

• ADHD
  • Problems with cognitive control²²
• Oppositional defiant disorder (ODD)
  • high desire for rewards²²
• Depression (especially in adolescents)
  • low desire for rewards²²
• Anxiety disorder (especially in adolescents)

Prevalence: in primary school children approx. 1.5%, in adolescents approx. 5%.⁵⁷
Oppositional defiant disorder is said to be present in 46.9% of children with ADHD and social behavior disorders in a further 18.5%.⁵
Comorbidity between ADHD-HI and Disorder of Social Behavior is reported in 15 to 85% of cases, depending on the study design and direction of the correlation, i.e. 4.7 times more frequently overall than in those not affected.⁵⁸
Oppositional defiant behavior and other social disorders are considered by some experts to be a subtype of ADHD (rage type). We suspect that this is more of a separate disorder that has a high comorbidity with ADHD.

Differentiation from ADHD: Aggression in people with (pure) ADHD is reactive, defense motive, no intention to harm.⁵⁹⁶⁰ Aggression in people with ADHD often arises from a misjudgement of situations, after which they (supposedly rightly) defend themselves. People with ADHD therefore show reactive rather than proactive aggression.⁶¹

2.5.9. Emotionally unstable personality disorder / borderline personality disorder (1 - 5 % (women), 1 % (men))¶

This section has been moved to a separate article: Emotionally unstable personality disorder / borderline personality disorder

2.5.10. Obsessive-compulsive disorder (1 to 3 %)¶

Source²

Prevalence: Lifetime prevalence of 1 to 3 %,⁶²⁶³ according to other sources 4.2 % of all women, 3.5 % of all men within one year.¹
Girls under 18 years: Prevalence 0.96%, boys 0.63%.¹⁴

Olfactory disorders (disorders of the sense of smell) are common in ASD and OCD, but not in ADHD.⁶⁴

2.5.11. Antisocial personality disorder (0.2 - 3 %)¶

Source⁶⁵

• High impulsiveness
• Strong novelty seeking / sensation seeking
• Self-centeredness / egocentrism
• Lack of empathy towards others
  • Not being able to feel how others feel

Subgroups of antisocial personality disorder:

• Impulsive type
  • Frequent comorbidity with ADHD-HI / ADHD-C
  • Emotionally highly sensitive / hyper-reactive
  • Increased excitability
  • High impulsiveness
  • Reactive aggression - as an immediate reaction to triggers
  • Low stress tolerance
• Psychopathic type
  • Rare comorbidity with ADHD-HI / ADHD-C
  • Emotionally insensitive / hyporeactive
  • Active aggression - purposeful, instrumental violence
  • No increased arousal in case of frustration
  • No reduced stress tolerance

Differentiation from ADHD: Aggression in (pure) persons with ADHD is reactive, defense motive, no intention to harm ^{59 60} Aggression in people with ADHD often arises from a misjudgment of situations, according to which they (supposedly rightly) defend themselves. We see a connection between this and rejection sensitivity as an exaggerated sensitivity to perceived or actual rejection/offensiveness. People with ADHD therefore show a reactive and not a proactive aggressiveness⁶¹
Persons with ADHD often recognize their sudden aggressive or verbal lapses or impulse control disorders as inappropriate with only a little distance and are usually able to excuse themselves, unlike people with psychopathic personality structures.⁶⁶

Common symptoms of antisocial personality disorder and ADHD:⁹

• Impulsivity (atypical for ADHD-I)
• Rapid mood swings

ADHD symptoms that are atypical of antisocial personality disorder:

• Inner restlessness (typical in atypical depression, less so in melancholic depression)
• Concentration problems
• Attention problems
• Dysphoria with inactivity
• High flow of speech (logorrhea, polyphrasia)
• Chasing thoughts, circling thoughts

Symptoms of antisocial personality disorder that are atypical of ADHD:

• Criminal behavior
• Deception of others
• Disregard for oneself and others
• Lack of remorse

2.5.12. Narcissism (0.5 to 2.5 %)¶

Prevalence 0.5 % to 2.5 %.

Narcissism and ADHD share some possible symptoms. They are similar:

• Depressive symptoms
  • Feeling of inner emptiness
  • Dejection
• Unspecific fears
• Relationships with other people strained or disturbed
  • Devaluation of others to emphasize own value (only narcissism)
• Emotional problems
  • With narcissism, as with ADHD, increased problems perceiving and living one’s own feelings and needs
• Disorder of self-esteem
  • With narcissism, as with ADHD, increased sickliness. ⇒ Rejection sensitivity: offendedness / sensitivity to rejection and criticism as a specific ADHD symptom

2.5.13. Schizophrenic Disorder (1 %)¶

The lifetime prevalence is around 1%.⁶⁷
Girls under 18 years: Prevalence 0.76%, boys 0.48%.¹⁴

Schizophrenia is highly hereditary (like ADHD approx. 80 %)⁶⁸ and usually only develops after adolescence. However, it is usually preceded by precursors from childhood that do not resemble schizophrenia itself, but appear to genetically indicate schizophrenia.⁶⁹

The negative symptoms of schizophrenia are based on a lack of dopamine. They are similar to ADHD symptoms.
The positive symptoms, on the other hand, are based on excessive subcortical presynaptic dopamine transmission (dopamine hypothesis). Although this is reduced by antipsychotic dopamine D2 receptor antagonists, in schizophrenia D2/D3 receptors appear to be only very slightly increased and DAT not altered at all, so that other medication approaches may be more appropriate.⁷⁰
The excessive subcortical dopamine drive is likely due to changes in cortical function, specifically the reduction in cortical NMDA receptor-mediated glutamate signaling, which impairs cortical dopamine and GABA function. These cortical changes are thought to cause the cognitive impairments and negative symptoms of schizophrenia.⁶⁸

Schizophrenia is also thought to be caused by a combination of genetic factors, environmental influences and physical and psychological factors. Emotional trauma, social stress and hallucinogenic drugs have been identified as environmental influences for schizophrenia.
⇒ Genes + early childhood stress as a cause of other mental disorders

The COMT rs4680 involved in schizophrenia (as one of 50 or more candidate genes) enhances the degradation of dopamine and noradrenaline by forming a more active and thermally stable COMT enzyme.⁷¹ This causes higher schizotypal symptoms.
This can be reconciled with the newer dopamine hypothesis, according to which the positive symptoms of schizophrenia are not caused by a generally increased dopamine level in the frontal cortex (and in the nucleus accumbens, a part of the striatum), but by an increased activity (firing rate) of the mesolimbic system, which in turn is caused or influenced by a dopamine deficiency in the ventral tegmentum.⁷¹

Schizophrenia and attention:

• Increased sensitivity to sensory stimulation⁵⁹
• High sensitivity causes sensory overload⁵⁹
• Attention selection for individual events disturbed⁵⁹
• Concentration / maintaining concentration on relevant aspects of a task is disturbed.⁵⁹

Symptoms of schizophrenia that are atypical of ADHD:

• Drawings are non-spatial, no three-dimensional representation
• Irony / sarcasm are not understood
• Olfactory Disorders.⁶⁴

2.5.14. Psychoses (1 %)¶

2.5.15. Autism spectrum disorder (ASD) (0.9 %)¶

Sources⁷²⁷³²

Prevalence of ASA: approx. 0.9 %⁷⁴
How many people with ADHD also show ADHD symptoms is an open question. A meta-analysis of 23 articles found results of 2.6% to 95.5% for ASD without intellectual impairment.⁷⁵ Some sources assume that around 42%⁷⁶ to 50%⁷⁷⁷⁸ of all people with ADHD also suffer from ADHD.
One review concluded that ADHD and ASD may be a continuum.⁷⁹
It is likely that ADHD and autism have common neurological/genetic roots.⁸⁰

• Profound developmental disorder
  Prevalence: approx. 0.6 %⁷⁴
• Pathological Demand Avoidance (PDA)
  • Extreme resistance to any tasks not of their own choosing
    • Does not only affect individual areas of life
    • Also everyday tasks that could be done without any problems (e.g. brushing teeth, personal hygiene, homework)
    • Also activities that the person normally enjoys, if self-selected
    • Goes far beyond the normal level for the age group
    • Not linked to specific phases in child development (defiant phase)
    • Frequent use of a wide range of avoidance strategies (making excuses, delegating tasks, extreme to violent outbursts of anger)
    • Effort to avoid often exceeds the effort of the task
    • Avoidance patterns can be externalizing or internalizing
      • Externalizing: offensive, aggressive
      • Internalizing: silent resistance, masking, concealed
  • Psychological explanatory model
    • Extreme compulsion to control, fed by irrational fears
    • External requirements would be perceived as a loss of control and cause massive stress
    • Resistance results from fear rather than malice (such as Disorder of Social Behavior, CD)
      • Praise can fuel fear of future expectations instead of reinforcing them
      • Uncertainty about what is to come and what will happen reinforces PDA
  • Overlap with ADHD in that attention problems and hyperactivity are strongly associated with a lack of self-motivation for tasks that are not intrinsically interesting
    • Specific behavioral profile for autism or other child development disorders
    • Is not considered an independent diagnosis
  • Treatment
    • As we understand it, anxiety-relieving medication should be able to help, such as CBD
• Autism⁸¹
  Prevalence: approx. 0.3 %⁷⁴
• Asperger’s
  Prevalence: approx. 0.084 %⁷⁴
• Disintegrative Disorder⁸¹
  Prevalence: 0.008 % (one person with ADHD in 12,500 people)⁷⁴
• Rett syndrome⁸¹
  Prevalence: 0.006 % (one person with ADHD in 10,000 to 17,000 people)⁸²⁷⁴
  Only applies to girls
  Symptoms of Rett syndrome⁸²
  • Stereotypes of the hands (washing movements)
  • Partially autistic behavior
  • Dementia
  • Reduced head growth
  • Epileptic seizures (later stage)
  • Spasticity (later stage)
  • Apraxia
  • Muscle atrophy
  • Movement disorders in the area of the thorax
  • Social behavior and play development severely inhibited
  • Social interest continues to exist
• Both ASD and ADHD show downregulation of neuroligin genes, which was even more pronounced in ASD.⁸³

Differential diagnosis of ADHD:

Children with ASD had 15 or more of the 30 symptoms (average: 22 = 73%) of the Checklist for Autism Spectrum Disorder symptoms, while children with ADHD had an average of 4 symptoms (13.3%), none of them 15 or more. ADHD symptoms, on the other hand, were prevalent in children with ASD.⁸⁴
Children with ADHD showed increased scores on the Social Responsiveness Scale (SRS), but these did not come close to the scores of people with ASD.⁸⁵

The case for ASS:⁸⁶

• Inattention rather due to too much detail orientation in ASD (compared to overlooking details in ADHD)⁷⁸
• Concentration breaks down when routines are disordered in ASD (compared to lack of routines and rapid jumping between different things in ADHD)
• The unexpected is seen as an unpleasant irritation and a disorder of one’s own structure (rather than a welcome change in ADHD)
• Routines due to their own need for structure (as opposed to laboriously getting used to routines so as not to lose too much structure with ADHD)
• Great difficulty in social situations due to inner insecurity about how to behave correctly (as opposed to being offended by thoughtless behavior in ADHD)
• Difficulty grasping social rules of the game (compared to difficulty adhering to the well-grasped social rules of the game in ADHD)
• High attention to detail exceeds the time frame for activities (compared to project interruptions due to changes of interest in ADHD)
• Needs order for his own inner structure, tends to find things in disorder (compared to not being able to maintain order due to other priorities with ADHD)
• Deviation from the plan leads to irritation (compared to frequent deviations from the plan due to own spontaneity and impulsiveness)
• Reduced flexibility (compared to less impaired flexibility in ADHD)
• Concentration can be maintained during prolonged and repetitive tasks (compared to difficulties in maintaining concentration during monotonous boring tasks in ADHD)
• Motor restlessness tends to occur in restless situations as a way of reacting (compared to motor restlessness in calm situations to stimulate ADHD)
• Motor restlessness rather out of aversion to something = running away (as opposed to out of interest in something = running towards in ADHD)
• Loose conversations or small talk unpopular, as own thought structures are thwarted; sometimes compensation through strict conversation (this is not present in ADHD; in our opinion, this is already present in ADHD, but weaker)
• Lack of feeling for the situation and mood (present in ADHD)
• Interrupting others rarely (like ADHD-I, different from ADHD-HI / ADHD-C)
• Having to wait in a rather dark, completely stimulus-free room is a rather pleasant idea (very unpleasant with ADHD-HI / ADHD-C; both possible with ADHD-I)

In ASD, the intracortical pathway (facilitation) appears to be unimpaired, whereas in ASD with comorbid ADHD, the intracortical pathway appears to be impaired. This could represent a biomarker to distinguish ASD from ADHD.⁸⁷

Both ASD and ADHD showed slower orienting responses to relatively unexpected spatial target stimuli compared to controls, which was associated with higher pupil dilation amplitudes in ASD. ADHD showed shorter cue-evoked pupil dilation latencies than ASD and controls.⁸⁹

Several studies have looked at differences between ASD and ADHD.

ASD symptoms that are atypical for ADHD:

• Less verbal comprehension with ASD than with ADHD⁹⁰
• Lower vocabulary with ASD⁹⁰
• Less comprehension with ASD⁹⁰
• Poorer image concepts with ASD⁹⁰
• Poorer image completion with ASS⁹⁰
• Slower processing speed with ASD⁹⁰
• Lower social judgment with ASD⁹⁰
• Poorer response to name calling at the age of 24 months with ASD⁹¹
• Higher shifting with ASS⁹²
• Poorer emotional self-regulation with ASD⁹²
• ASD, like dyslexia, shows deficits in global motion processing, unlike ADHD. ASD and dyslexia show significantly lower flicker fusion frequency than healthy controls or ADHD subjects.⁹³
• Self-soothing through repetitive behavior and routines⁹⁴
• Strongly differentiated need for relationships Important to be able to control the frequency and intensity of social contacts. Not resentful, but pragmatic.⁵⁰
• Shutdown: freezing and no longer being able to react.⁵⁰
• Meltdown: Openly aggressive outbursts, including physical attacks or pushing, in order to defend one’s own boundaries.⁵⁰
  • Sometimes self-injurious behavior to relieve tension is also possible here⁵⁰

ADHD symptoms that are atypical for ASD:

• Poorer working memory typical for ADHD, less so for ASD⁹⁰⁹²
• Attention regulation problems⁹⁴
• Planning and organization problems (which are largely determined by working memory) typical for ADHD, less so for ASD⁹²
• Inhibition problems typical for ADHD, less so for ASD⁹²
• Fewer points in the Digit Span for ADHD than for ASD⁹⁰
• Poorer graphomotor processing in ADHD⁹⁰
• Novelty seeking typical for ADHD, not for ASD⁹⁴
• Hyperactivity⁹⁴
• An above-average number of glances into the eyes of the other person, even compared to non-affected people⁹⁵
• Risky behavior: Fun through overstimulation⁵⁰

Both ADHD and ASD show structural abnormalities in the PFC, cerebellum and basal ganglia. Persons with comorbid ASD and ADHD showed no significant differences in the volumes of the PFC, cerebellum or basal ganglia. However, they showed significantly lower volumes of the left postcentral gyrus, but only children, not adolescents.⁹⁶
One review compared catecholaminergic and cholinergic neuromodulation in ASD and ADHD:⁹⁷

• Stimulants may be a viable treatment option for a (possibly genetically defined) ASD subgroup
• disorder of the cerebellum is much more common in ASD than in ADHD
  • in both cases, this could open up a noradrenaline- or acetylcholine-controlled treatment option
• a deficit of the cortical salience network is considerable in subgroups of ASD such as ADHD
  • Biomarkers such as eye blink rate or pupillometric data can predict efficacy of targeted treatment of an underlying deficit using dopamine, noradrenaline or acetylcholine, in ADHD as in ASD

ASD is characterized by high levels of aggression and risk-taking behaviour. In addition, ASD is involved in child abuse with above-average frequency.⁹⁸ Aggression and high-risk behavior are also characteristics of the ADHD-HI subtype.

A review article found approximately doubled noradrenaline levels in the blood of those with ADHD and approximately halved noradrenaline levels in the blood of those without ADHD. In contrast, serotonin blood levels were four times higher in those with ASD and more than four times lower in those with ADHD.⁹⁹

The ability to recognize irony was also impaired in children with ADHD.¹⁰⁰

2.5.16. Fragile X syndrome (0.22% (men) to 0.66% (women))¶

Prevalence: 1/150 (0.66%) women, 1/456 (0.22%) men in the USA¹⁰¹
Source²⁴²

2.5.17. Pervasive developmental disorders (PDD) (0.06 %)¶

Prevalence: 60/100,000 (0.06 %)

PDD is characterized by severe deficits in social behavior and communication, as well as repetitive and stereotypical interests and behaviors. There are often comorbidities with reduced intelligence, ADHD, aggression and obsessive-compulsive disorder.¹⁰²

2.5.18. Wilson Disease (0.0033 %)¶

Wilson’s disease (prevalence: 1 in 30,000 people, 0.0033%) is associated with excessive copper levels.
People with ADHD show symptoms that can be confused with ADHD¹⁰³
Wilson disease is associated with an ATP7B gene defect and shows an excess of copper.
Although dopamine β-hydroxylase, which converts dopamine to noradrenaline, is dependent on copper for this, it does not appear to be involved in Wilson’s disease.

2.5.19. Monoamine neurotransmitter disorders¶

Monoamine neurotransmitter disorders are genetic defects in transporters or deficiencies in precursors, cofactors or degradation enzymes of monoamines (e.g. dopamine).¹⁰⁴

Symptoms of a severe dopamine deficiency can include¹⁰⁵

• Parkinson’s disease
• Dystonia
• Chorea
• oculogyric crises/gazing spasm
• Ptosis/eyelid muscle weakness
• Swallowing disorders
• myoclonic epilepsy
• Epileptic encephalopathy
• Progressive cognitive dysfunction
• Microcephaly
• Pyramid sign

Symptoms of a severe serotonin deficiency can include¹⁰⁵

• Temperature problems
• Sweating
• Dystonia

The measurement of pterins (especially biopterin and neopterin) in urine is helpful in detecting deficiencies in precursors and specific metabolic defects:

*GTP cyclohydrolase 1 deficiency (GCH 1)

• 6-Pyruvoyl tetrahydropterin synthase deficiency
• Dihydropteridine reductase deficiency
• Sepiapterin reductase deficiency
• Aromatic L-amino acid decarboxylase deficiency
  • 3-ortho-methyldopa increased
  • Vanillic acid increased
• Dopamine transporter deficiency syndrome (DTDS)
  • HVA to creatine ratio in urine increased
• Severe dopamine deficiency
  • Increased prolactin in the blood
  • Galactorrhea
• Strong excess of dopamine
  • Reduced prolactin in the blood

2.5.19.1. Genetically caused BH4 disorders (approx. 0.0002 %)¶

Genetic disorders of tetrahydrobiopterin synthesis (BH4, an important enzyme for dopamine synthesis) such as

• autosomal recessive (AR) guanosine triphosphate cyclohydrolase deficiency (GTPCH deficiency)
  • Prevalence less than 1 / 1,000,000 (less than 0.0001 %)¹⁰⁶
  • 46 % of all BH4 disorders
• 6-Pyruvoyl tetrahydropterin synthase deficiency (PTPS)
  • Prevalence: 1 / 500,000 to 1 / 1,000,000 (0.0001 % to 0.0002 %) ¹⁰⁷
  • 54 % of all BH4 disorders

seem to contribute to ADHD and other mental disorders such as anxiety, depression, aggression or oppositional defiant behavior.¹⁰⁸

See also Tyrosine hydroxylase In the article Dopamine formation.

2.5.19.2. Missing or greatly reduced DAT¶

There are (rarely) people with no or very severely reduced DAT. However, they show other symptoms that are not typical of ADHD (e.g. Parkinson’s dystonia in early childhood) and are therefore rarely misdiagnosed with ADHD and are more likely to be misdiagnosed with cerebral palsy. Many people with ADHD die as teenagers.¹⁰⁹ An excess of extracellular dopamine leads to reduced production of dopamine (and thus reduced storage of dopamine in the vesicles) through activation of presynaptic D2 autoreceptors, as well as downregulation or desensitization of dopamine receptors, resulting in a lack of phasic dopamine and a dopamine effect deficiency.¹⁰⁴

2.5.20. Predominantly milieu-related behavioral problems¶

Predominantly milieu-related behavioral problems means, for example, lack of attention and stimulation, physical and/or emotional abuse, media abuse, intrafamilial conflicts and sibling conflicts²
In our understanding, this description corresponds to the environmental causes of most mental disorders such as ADHD, depression, anxiety disorders, borderline etc., all of which can arise when environmental causes, usually stressful experiences in the first 6 years of life, permanently manifest an existing genetic disposition by means of epigenetic changes. Predominantly milieu-related behavioral abnormalities are therefore unsuitable for defining a separate disorder.
⇒ How ADHD develops: genes or genes + environment
⇒ Genes + early childhood stress as a cause of other mental disorders

2.5.21. Oppositional defiant behavior (ODD)¶

ADHD is characterized in particular by problems with cognitive control, whereas oppositional defiant disorder (ODD) is characterized by a high desire for reward.²²

2.5.22. Auditory processing and perception disorder (AVWS)¶

English: Auditory processing disorders (APD)¹¹⁰
AVWS is an independent disorder (ICD-10: F80.20).
Prevalence: 2 to 3 %, boys 4 to 6 %, girls 1 to 2 %¹¹¹

Even soft sounds and noises are heard normally. Peripheral hearing is intact.
The processing and perception of what is heard is impaired.
The impairment is not due to a reduction in intelligence. Non-verbal intelligence is unimpaired.
Functional deficits in auditory information processing and perception:

• correct auditory perception is difficult or even impossible - auditory agnosia
• neuronal transmission, pre-processing or processing of acoustic or speech signals is impaired, e.g:
  • Localization (direction and distance of the sound source)
  • Discrimination (distinguishing between changes in time, frequency or intensity)
  • Selection (filtering out background noise)
  • Dichotic hearing (binaural hearing)

Consequences can be difficulties in difficult listening situations, such as

• Understanding speech with background noise
• Understanding speech from several simultaneous speakers

If the ability to distinguish sounds, speech sounds and noises is impaired at the same time (which is often the case), reading and writing difficulties can arise.
AVWS is therefore considered a neurocognitive risk, especially for learning at school.

Common comorbidities of AVWS are:¹¹⁰

• Speech development disorders
• circumscribed developmental disorders of school skills
  • e.g. reading and spelling disorders
• supramodal attention problems (attention deficit disorder)
• profound developmental disorders (e.g. ASD)