TABLE 1.
Participant characteristics
| Patients | Controls | p-values (Pt. vs. C) | |||||
|---|---|---|---|---|---|---|---|
| n | Mean | SD | n | Mean | SD | ||
| Age (years), baseline | 21 | 10.44 | (1.33) | 25 | 10.26 | (1.33) | .643 |
| Boys/Girls | 19/2 | 20/5 | .335 | ||||
| ADHD-C /ADHI-I | 17/4 | ||||||
| Children with a comorbid disorder | 4 | ||||||
| Methylphenidate mg/day | 20 | 27.63 | (9.34) | ||||
| Tanner stage, baseline | 21 | 1.47 | (.79) | 25 | 1.76 | (1.24) | .361 |
| Tanner stage, follow-up | 17 | 1.40 | (.66) | 24 | 1.83 | (1.19) | .152 |
| BMI, baseline | 21 | 19.31 | (3.66) | 25 | 16.54 | (2.74) | .006 |
| BMI, follow-up | 15 | 18.98 | (3.89) | 23 | 16.76 | (2.24) | .058 |
| Systolic blood pressure, baseline | 20 | 103.95 | (6.43) | 23 | 101.70 | (10.65) | .414 |
| Diastolic blood pressure, baseline | 20 | 64.80 | (4.79) | 23 | 65.00 | (8.58) | .924 |
| Systolic blood pressure, follow-up | 17 | 106.41 | (8.14) | 24 | 111.63 | (13.29) | .159 |
| Diastolic blood pressure, follow-up | 17 | 67.88 | (6.90) | 24 | 66.92 | (7.95) | .688 |
| Physical activity score (median, IQR) | 20 | 3.0 | [2.0; 4.0] | 24 | 3.0 | [3.0;4.0] | .179 |
TABLE 2.
Inclusion and exclusion criteria
| Patients |
|---|
Inclusion criteria
|
Exclusion criteria
|
Controls
|
Exclusion criteria
|
[i] Note. MPH = methylphenidate; IQ = intelligence quotient; KSADS-PL = Kiddie Schedule for Affective Disorders and schizophrenia for school-age children - Present and Lifetime Version; ADHD-rs = Attention Deficit Hyperactivity Disorder -Rating Scale; BRIEF = behaviour rating inventory of executive function.
FIGURE 1.
Study flow
* Excluded due to suspected autism
** Six patients declined blood sampling
*** Four controls declined blood sampling
⁰ Three patients did not want to undergo blood sampling.
⁰⁰ Blood samples could not be obtained from one control participant.
˟ Two patients could not be pricked for blood sampling at baseline.
˟ ˟ One patient dropped out because he did not want to take the prescribed medication.
˟ ˟ ˟ One control dropped out due to time concerns from the family.
TABLE 3.
Fasting plasma BDNF levels (pg/ml) in the ADHD and healthy control groups at baseline and follow-up
| Patient group | Control group | Patients vs. controls | |||||||
|---|---|---|---|---|---|---|---|---|---|
| n | Median | Q1 | Q3 | n | Median | Q1 | Q3 | p | |
| Baseline | 19 | 47.12 | 37.70 | 58.61 | 25 | 41.22 | 22.61 | 49.71 | .044 |
| Follow-up | 15 | 42.58 | 29.91 | 70.47 | 23 | 26.38 | 21.73 | 34.32 | .007 |
| Baseline to follow-up change | 13 | −0.70 | −10.81 | 26.11 | 23 | −0.56 | −16.26 | 2.93 | .026 |
FIGURE 2.
Fasting BDNF levels (pg/ml) in patients and healthy controls at baseline (0_green) and follow-up (12; red).
FIGURE 3A.
ADHD-rs scores, rated by parents.
FIGURE 3B.
ADHD-rs scores, rated by teachers.
FIGURE 4A.
Correlation between baseline BDNF levels and improvement in parent-rated ADHD-rating scale inattention symptom scores.
Note. BDNF = Brain-Derived Neurotrophic Factor; ADHD-rs = ADHD-rating scale.
FIGURE 4B.
Correlation between baseline BDNF levels and improvement in parent-rated ADHD-rating scale hyperactivity symptom scores.
Note. BDNF = Brain-Derived Neurotrophic Factor; ADHD-rs = ADHD-rating scale.
TABLE 4.
Spearman correlations between baseline-to-follow-up changes in plasma BDNF levels and ADHD symptom scores in the ADHD group.
| Symptom change scores | r | p |
|---|---|---|
| Inattention (parent) | .32 | .29 |
| Hyperactivity (parent) | .52 | .07 |
| Behaviour (parent) | .23 | .44 |
| Inattention (teacher) | −.11 | .73 |
| Hyperactivity (teacher) | .04 | .90 |
| Behaviour (teacher) | .21 | .51 |