Symptom development in children by age and frequency

Author: Ulrich Brennecke
Review: Dipl.-Psych. Waldemar Zdero

The symptoms of ADHD vary according to age, from infancy to adulthood.
In infancy, early symptoms such as restlessness, increased activity and sleep problems may indicate an increased risk of ADHD.
Symptoms in infancy include distractibility, chaotic play behavior and motor problems.
In preschool age, ADHD-I can show anxious and withdrawn behavior, while hyperactive and impulsive behavior is already noticeable in ADHD-HI.
At school age, other ADHD symptoms are added, such as attention problems, learning difficulties, emotional and social problems.
In adolescence, ADHD can be associated with increased risk-taking behavior and addiction.
In adulthood, earlier hyperactivity decreases and inner restlessness becomes more visible. Affective comorbidities such as depression or anxiety disorders can also occur. ADHD can also first manifest itself in adulthood, particularly in women from their late 30s onwards.

Non-affected people also have individual ADHD symptoms. However, people with ADHD have significantly more ADHD symptoms than people without ADHD. However, the diagnosis is not only based on the presence of certain symptoms, but also on their intensity and long-term presence in various areas of life. It is important to distinguish ADHD from temporary stress or strain.

Many of the symptoms listed below are basically typical for children. Nevertheless, naming them is relevant, because the difference lies in the degree of occurrence, which in ADHD clearly exceeds that of peers. The mere occurrence of more severe symptoms compared to peers is not a compelling reason to make a diagnosis. Some children have developmental delays that disappear over time. Nevertheless, these should be observed at an early stage without pathologizing them so that timely intervention can be made if they become severe enough to require support or treatment. For preschool children, one of the most effective forms of treatment is training the parents to interact appropriately with the child and to develop an understanding of the child’s individual problems.

• 1. Symptom development of ADHD-HI (with hyperactivity) by age
  • 1.1. Infancy - early symptoms of ADHD
  • 1.2. Infant age (1 - 3 years)
  • 1.3. Preschool age (4 - 6 years)
    • 1.3.1. ADHD-I at preschool age (without hyperactivity)
    • 1.3.2. ADHD at preschool age (with hyperactivity)
  • 1.4. School years (6 to 15 years)
    • 1.4.1. ADHD-I at school age (without hyperactivity)
    • 1.4.2. ADHD-HI at school age (with hyperactivity)
  • 1.5. Adolescence (from 15 years)
  • 1.6. Adulthood
• 2. Symptom frequency and symptom intensity in ADHD
• 3. Ethnic and cultural differences

1. Symptom development of ADHD-HI (with hyperactivity) by age¶

1.1. Infancy - early symptoms of ADHD¶

ADHD (and ASD) symptoms can already be detected in infancy.¹
One study was able to distinguish those with a high genetic risk of ADHD (older siblings or parents with ADHD) from those without a genetic risk of ADHD in children at 1 month of age based on behavior (primarily increased activity and impulsivity and more frequently reported behavior and temperament problems).²

The following early symptoms in infants correlate with an increased risk of ADHD in later years:

• Restlessness, hypermotoric
  • Restlessness
    • Approx. 60 % of children show extreme restlessness³
    • Restlessness at 6 months correlated with ADHD symptoms at 37 and 54 months, independent of the early symptom of shortened sleep duration⁴
  • Uninterrupted urge to move³
  • Inexhaustible energy⁵
  • No crawling, early walking⁶
  • Restless, unbalanced⁶
  • Playing time shortened⁶
  • Difficulties in establishing a calm waking state⁵
• Sleep
  • Unstable wake and sleep rhythm³
  • Superficial sleep, wide awake⁶
  • Short sleeper⁵
    • Normal sleepers before 18 months showed significantly fewer ADHD symptoms at 37 months than long-term short sleepers⁴
  • Regulatory problems (excessive crying, sleep or feeding problems) that occurred in parallel (multiple) or persistently at 5, 20 or 56 months of age predicted increased internalizing (p = .001), externalizing (p = .020) and overall behavioural problems (p = .001), in particular more depressive (p = .012), somatic (p = .005), avoidant (p < .001) and antisocial personality problems (p = .006) than in children who never had regulation problems . The risk of an ADHD diagnosis was increased (p = .017), especially of the hyperactive/impulsive subtype (p = .032). IQ was not correlated.⁷
• Crying, screaming
  • Particularly frequent, persistent and shrill crying³⁵
  • Insatiable crying at times⁶
  • Regulatory problems (excessive crying, sleep or feeding problems) that occurred in parallel (multiple) or persistently at 5, 20 or 56 months of age predicted increased internalizing (p = .001), externalizing (p = .020) and overall behavioural problems (p = .001), in particular more depressive (p = .012), somatic (p = .005), avoidant (p < .001) and antisocial personality problems (p = .006) than in children who never had regulation problems . The risk of an ADHD diagnosis was increased (p = .017), especially of the hyperactive/impulsive subtype (p = .032). IQ was not correlated.⁷
• Feeding problems
  • Drinking problems⁶⁵
  • Hot eater⁵
  • Frequent colic⁵
  • Regulatory problems (excessive crying, sleep or feeding problems) that occurred in parallel (multiple) or persistently at 5, 20 or 56 months of age predicted increased internalizing (p = .001), externalizing (p = .020) and behavioral problems overall (p = .001), especially more depressive (p = .012), somatic (p = .005), avoidant (p < .001) and antisocial personality problems (p = .006) than in children who never had regulation problems. The risk of an ADHD diagnosis was increased (p = .017), especially of the hyperactive/impulsive subtype (p = .032). IQ was not correlated.⁷
• Cleanliness education often delayed³
• Language development often delayed³
• Stroking is not enjoyed⁶
• Frequent skin allergies⁶
• Higher level of negative affect (already at the age of 3 months)⁸
  • The results for positive affect did not reach statistical significance
  • Simultaneous observation of the progression of positive and negative emotionality can generate additional information
  • Negative affect only correlated with ADHD symptoms in childhood if moderate, stable or low positive affect was present at the same time
• Anger
  • Correlates with ADHD symptoms at 4 years of age⁹
• High-need baby, Dermandingness
  • Correlated with ADHD symptoms at 4 years of age¹⁰
  • Correlated with hyperactivity at 8 and 11 years of age¹¹¹²
• Resistance to control
  • Highly correlative to externalizing symptoms at 8 years of age¹³
• Wandering around with nothing to do during a two-hour home visit
  • Significant predictor of individual differences in children’s impulse control and disengagement behavior during free play¹⁴

1.2. Infant age (1 - 3 years)¶

• Distractibility⁵
• Chaotic and destructive, less goal-oriented play behavior³
• Sleep problems
  • Sleep-through problems in toddlers 1 to 3 years old were a stronger predictor of later ADHD than sleep duration.¹⁵
  • Sleep disorders⁵
  • Regulatory problems (excessive crying, sleep or feeding problems) that occurred in parallel (multiple) or persistently at 5, 20 or 56 months of age predicted increased internalizing (p = .001), externalizing (p = .020) and overall behavioural problems (p = .001), in particular more depressive (p = .012), somatic (p = .005), avoidant (p < .001) and antisocial personality problems (p = .006) than in children who never had regulation problems . The risk of an ADHD diagnosis was increased (p = .017), especially of the hyperactive/impulsive subtype (p = .032). IQ was not correlated.⁷

• increased activity level¹⁶
  • at the age of 18 and 24 months¹⁷
  • not yet 12 months old¹⁸¹⁷

• Gross motor problems¹⁶
  • above-average gross motor skills compared to controls¹⁹ whereby the study quality was criticized¹⁶
  • gross motor delay at 18 months of age when controlling for gender and socioeconomic status²⁰
  • Often falls over his own legs²¹
  • Mouth motor skills noticeable²¹
    • Mouth is often open
    • Drools easily
  • Desire for violent movements⁵
  • Constantly on the move⁵
  • Sometimes very skillful motor skills⁵

• Fine motor skills¹⁶
  • parental fear of fine motor impairment correlated with later ADHD traits²²
  • fine motor delays correlated with an ADHD diagnosis after 18 months²⁰
  • a large study (n = 1,664) found no significant group differences in general fine motor skills in the first 15 months¹⁹ although the study quality was criticized¹⁶

• Playing time shortened²¹
  • Changes employment frequently
  • Does not finish the game
• Learning problems
  • No learning gain through negative experiences³
  • Learns to dress with difficulty²¹
  • Language development delayed²¹²³
  • Conversion problems²¹
  • Adaptation problems²¹
• Can’t wait²¹
  • Until it is your turn
• Sensitivity changes
  • Highly sensitive or hyposensitive to external stimuli²¹
• Novelty Seeking
  • Stimulation hunger⁵
  • Enormously curious⁵
  • Daring, increased risk of accidents⁵
• ADHD-HI specific:
  • Group incompetence and disruptive behavior, outsider role³
  • Constant fidgeting and interrupting in the chair circle³
  • Strong urge to move leads to danger to self and others³
  • No awareness of danger³
  • Impulsiveness
    • Impulsivity at age 2 correlated with ADHD symptoms at age 3.²⁴
  • Irritability
    • Significant irritability at 3 years of age was predictive of clinical diagnoses
      • At the age of 6 years (depression, oppositional behavior disorder and functional impairment. Irritability also correlated with parental depression and anxiety)²⁵
      • At age 9 (current and lifetime anxiety disorders at age nine, current and lifetime generalized anxiety disorder and current separation anxiety, depressive symptoms, disruptive behavior, major functional impairment, and use of outpatient treatment)²⁶
      • Between the ages of 12 and 15 (internalizing and externalizing disorders in adolescence, anxiety and depressive symptoms as well as major functional impairments, in particular poorer peer relations, poorer physical health, use of antidepressants)²⁷
  • Emotional dysregulation
    • Aggression
      • Increased aggression³
      • Little tyrant⁵
      • Destruction of games and toys⁵
    • Anger
      • Frequent / uncontrollable fits of rage³⁵
    • Affect spasms⁵
    • Affectively unstable, mostly pronounced defiant phase⁵
• ADHD-I specific:
  • Remarkably calm and well-behaved²¹
  • Overanxious, clinging, very affectionate²¹
• A meta-analysis found a predictive power of symptoms in the first 36 months for later ADHD in childhood:²⁸
  • Activity level (k = 18) in infancy and toddlerhood correlated moderately with ADHD (ADHD-C only)
  • Sustained attention correlated moderately negatively with ADHD (all subtypes)
  • Negative emotionality correlated moderately with ADHD (all subtypes)
• Persistent primitive reflexes (reflexes that should already be degraded) can be an indication of developmental delays. More on this under Persistent (primitive) reflexes (RPR) in the article *Motor symptoms of ADHD *

1.3. Preschool age (4 - 6 years)¶

ADHD is already apparent at kindergarten age. A long-term study was able to identify 81% of children who were diagnosed with ADHD 4 years later as early as kindergarten age using a model of machine learning.²⁹

1.3.1. ADHD-I at preschool age (without hyperactivity)¶

• Often anxious²¹
• Often unsafe²¹
• Learning difficulties
  • Problems listening²¹
  • Slow comprehension²¹
  • Often believes he cannot cope with the task²¹
  • Slow language acquisition, confuses letters²¹
• Gross motor skills
  • Conspicuous oral motor skills²¹
  • Speaks indistinctly²¹
  • Does not like to paint or do handicrafts²¹
  • Motor problems²¹
  • Difficulties learning to swim²¹
  • Difficulties learning to ride a bike
  • Balance problems
  • Activities slowed down or too fast²¹
• Fine motor skills impaired³⁰
• Withdrawn social behavior
  • Often plays alone²¹
  • Little contact with children of the same age²¹
  • Withdrawal tendencies in groups²¹
    • Kindergarten
    • Circle of chairs
  • Gets bored quickly²¹
• Often loses and forgets things²¹
• Regulatory problems (excessive crying, sleep or feeding problems) that occurred in parallel (multiple) or persistently at 5, 20 or 56 months of age predicted increased internalizing (p = .001), externalizing (p = .020) and overall behavioural problems (p = .001), especially more depressive (p = .012), somatic (p = .005), avoidant (p < .001) and antisocial personality problems (p = .006) than in children who never had regulatory problems. The risk of an ADHD diagnosis was increased (p = .017), especially of the hyperactive/impulsive subtype (p = .032). IQ was not correlated.⁷
• Increased emotional dysregulation as well as slower reductions in emotion dysregulation at ages 3, 5, and 7 predicted higher ADHD symptoms, conduct problems, and internalizing problems at age 7 in both boys and girls.³¹
• Persistent primitive reflexes (reflexes that should already be degraded) can be an indication of developmental delays. More on this under Persistent (primitive) reflexes (RPR) in the article *Motor symptoms of ADHD *

1.3.2. ADHD at preschool age (with hyperactivity)¶

• Motor hyperactivity
  • Motor restlessness²¹
  • Always on the move²¹
• Impulsiveness
  • Gets excited quickly and strongly²¹
  • Reacts spontaneously and rashly²¹
  • Asks a lot²¹
    • Often does not wait for answers²¹
  • Does not adhere to rules²¹
    • Often forgets rules again³²
  • Grumbles quickly²¹
• Attention problems
  • Often only become apparent at an older age (school years)
  • Cannot listen for long²¹
  • Forgets quickly²¹
  • Loses a lot²¹
• Aggression
  • Often as a comorbidity
  • Especially in case of uncertainty²¹
• Gross motor skills
  • Conspicuous oral motor skills³³
  • Language problems
    • Speaks indistinctly²¹
    • Stammer²¹
    • Difficulties with some consonants
  • Does not like to paint or do handicrafts³³
  • Holds pens cramped²¹
  • Presses too hard²¹
  • Coloring or cutting out shapes makes it difficult²¹
  • Difficulties learning to swim
  • Difficulties learning to ride a bike
  • Balance problems
• Fine motor skills impaired³⁰
• Social behavior
  • Strong sense of justice²¹
  • High ambition in sports and games²¹
  • Often wants to determine²¹
  • Eager for social services²¹
  • Quickly offended³⁴
    • Rejection Sensitivity
• Impatience
  • With itself²¹
  • With others²¹
• Wets more frequently²¹
  • More often during the day than at night
• Sleep
  • Frequently falling asleep late²¹
  • Needs little sleep²¹
• Executive function problems at preschool age
  • Correlated with more externalizing and attention symptoms, but fewer internalizing symptoms at the age of 8 to 13 years³⁵
  • Similar for an older age group³⁶
• Persistent primitive reflexes (reflexes that should already be degraded) can be an indication of developmental delays. More on this under Persistent (primitive) reflexes (RPR) in the article *Motor symptoms of ADHD *

1.4. School years (6 to 15 years)¶

ADHD symptoms do not usually become fully apparent until the school years.³

Sleep problems at the age of 8 to 9 years increased the risk of ADHD at the age of 10 to 11 years by 18 to 20%³⁷

1.4.1. ADHD-I at school age (without hyperactivity)¶

• Emotional problems
  • Often anxious²¹
  • Often unsafe²¹
  • Dares to do nothing²¹
  • Rejection Sensitivity
    • Easily offended²¹
    • Cries quickly²¹
    • Emotionally sensitive²¹
    • Poorly tolerates criticism²¹
    • Feels unloved²¹
    • Feels misunderstood²¹
• Attention and learning difficulties
  • Problems listening²¹
  • Easily distractible²¹
  • Forgets a lot²¹
  • Overhears a lot²¹
  • Unfocused²¹
    • Unless something is of particular interest
  • Dreamy²¹
  • Slowly²¹
  • Inflexible thinking²¹
  • Takes a very long time to do homework²¹
  • Cannot do homework alone²¹
• Gross and fine motor problems
  • Writing problems
  • Coloring unclean²¹
  • Speaks indistinctly²¹
• Social behavior
  • Is easily annoyed²¹
  • Can defend himself badly²¹
  • Delayed development of social maturity²¹
  • Gets bored quickly²¹
• Often loses and forgets things
• Somatization tendencies
  • Frequent headaches²¹
  • Frequent abdominal pain²¹

1.4.2. ADHD-HI at school age (with hyperactivity)¶

• Social behavior
  • Integration into the class group very difficult³
• Aggression
  • Hits frequently, is often beaten by others³
• Risk behavior
  • Can assess dangers poorly²¹
  • 85 % of accidents on the way to school³
• Attention problems become recognizable for the first time
  • From the age of 7 at the earliest
  • Up to the age of 14, 15 years
• Motor hyperactivity
  • Motor restlessness²¹
  • Always on the move²¹
  • Fidgets a lot²¹
  • Physical activity is a predictor of the ADHD symptoms of hyperactivity and inattention if it is continuous and sustained³⁸
• Gross motor skills
  • Poor power metering²¹
• Impulsiveness
  • Gets excited quickly and strongly²¹
  • Reacts spontaneously and rashly²¹
  • Interrupts others
  • Answers before the question is finished²¹
  • Is often loud²¹
• High sensitivity
  • Is often sensitive to noise himself³²
• Attention problems
  • Often only become apparent at an older age (school years)
  • Cannot listen for long²¹
  • Forgets quickly²¹
  • Loses a lot²¹
  • Concentration span limited
    • Frequently switches back and forth between tasks / activities²¹
  • Often paints on the side
  • Difficulties starting homework²¹
  • Interrupts homework frequently²¹
  • Good powers of observation²¹
    • Notices a lot²¹
    • Can see through others well²¹
• Learning problems
  • Makes mistakes again and again
  • Does not learn from mistakes²¹
• Gross motor skills
  • Conspicuous oral motor skills³³
  • Language problems
    • Speaks indistinctly²¹
    • Stammer²¹
    • Difficulties with some consonants
  • Does not like to paint or do handicrafts³³
  • Holds pens cramped²¹
  • Presses too hard²¹
  • Coloring or cutting out shapes makes it difficult²¹
  • Difficulties learning to swim
  • Difficulties learning to ride a bike
  • Balance problems
• Emotional dysregulation
  • Rejection Sensitivity
    • Quickly feels unfairly treated²¹
• Social behavior
  • Strong sense of justice²¹
    • Altruistic behavior
  • Often wants to determine²¹
  • Gets on worse with peers than with younger or older people²¹
• Collects useless things²¹
• Sleep
  • Often fall asleep late

1.5. Adolescence (from 15 years)¶

• Motor hyperactivity is reduced³
• Inner and outer restlessness²¹
• Impulsiveness and reduced attention remain³
• Orientation towards socially marginalized groups³
• Risk of developing an addiction³
• Willingness to engage in high-risk behavior³
• Frequent accidents³
• Drop in performance under stress²¹
• Organizational problems²¹
• Low determination²¹
• Spotty handwriting²¹

1.6. Adulthood¶

• Barely any motor hyperactivity, instead inner restlessness, feeling driven³⁹
• Attention problems subside somewhat
• Emotional problems / affective comorbidities on the rise
  • Depression
  • Anxiety disorders
• Increased risk of addiction, Disorders in social behavior⁴⁰
• Anxiety symptoms, alcohol problems⁴¹
• Criminal offenses ⁴²
• Increased tendency to have accidents⁴³
• Worse professional position⁴⁴

2. Symptom frequency and symptom intensity in ADHD¶

ADHD is not diagnosed by the presence of a specific type of symptom that is exclusive to ADHD (categorical), but by the set of symptoms that can originate from ADHD and their intensity (dimensional).⁴⁵⁴⁶

• In a collection of symptoms presented by Barkley⁴⁷
  • Non-affected people often experience 1 to 2 of the 18 symptoms on average, i.e. around 5 %
  • On average, people with ADHD often have 12 of the 18 symptoms mentioned, i.e. around 66%.⁴⁷
• In the online test we designed ourselves ⇒ ADHD online tests
  have
  • According to their own assessment, people with ADHD who were not affected had an average of just under 8 out of 32 possible symptoms (25 %)
  • Subjects with a confirmed ADHD diagnosis around 24 of the 32 possible symptoms (75 %)
• Hardly any person with ADHD has all the symptoms “often”, and it is barely possible to typify which symptoms occur more frequently together.

The symptoms must occur over a longer period of time and in several areas of life. They usually first become apparent before the age of 12. However, more and more cases of late onset ADHD are being recognized in which there were no sufficiently severe symptoms in adolescence to justify a diagnosis. This mainly affects women in their late 30s.
The fact that symptoms must persist for longer and in different areas of life serves to distinguish ADHD as a permanent disorder from symptoms of merely temporary (stress) exposure to temporary stressors.

3. Ethnic and cultural differences¶

When adults diagnose ADHD in children, the different ethnic and cultural backgrounds should be taken into account.⁴⁸