A longitudinal investigation of cognitive functioning and its relationship to symptom severity and academic functioning in treatment seeking youth with ADHD

		Groups
		ADHD		Controls
Baseline measures	n	Mean (SD)	n	Mean (SD)
WISC-IV/WAIS-IV	120/5		59/0
FSIQ	125	88.90 (12.67)	59	96.51 (9.71)
Verbal comprehension	125	93.43 (13.36)	59	95.12 (12.97)
Perceptual reasoning	125	97.06 (14.04)	59	101.41 (12.00)
Working memory	125	82.03 (12.95)	59	93.02 (10.45)
Processing speed	124	88.69 (13.59)	59	98.42 (11.06)
SNAP–IV	116	30.69 (10.58)	59	5.98 (6.81)

1 Notes. ADHD = attention deficit hyperactivity disorder; FSIQ = full-scale intelligence quotient; SD = standard deviation; SNAP-IV = The Swanson-Nolan-Pelham scale, version IV (ADHD-combined score). The SNAP-IV is measured in summary scores (0-54); the WISC-IV/WAIS-IV composite scores are measured in standardized composite scores, mean = 100, SD = 15

TABLE 2.

Descriptive clinical data of parent-rated comorbid symptoms at the baseline in the ADHD group

	Percentiles
FTF variables	< 90		≥ 90	< 98	≥ 98
	n	%	n	%	n	%
Motor skills	67	60	35	31	10	9
EF	14	12	62	55	36	32
Perception	46	41	51	46	15	13
Memory	39	35	58	51	16	14
Language	54	48	40	35	19	17
Learning	25	26	39	41	32	33
Social skills	38	34	56	50	19	17
Externalized	27	24	39	34	47	42
Internalized	59	52	38	34	16	14
Compulsivity	71	57	34	27	8	6

1 Notes. ADHD = attention deficit hyperactivity disorder; ES = executive functions; FTF = Five to Fifteen questionnaire

Linear diagram presenting slopes of the beta values for the Wechsler composite scores for the ADHD and Control groups between baseline and the 3-4 year follow-up and the slope differences.
*Notes.* β = Beta, not standardized. FSIQ = full scale intelligence quotient. In parenthesis 95% confidence interval. The beta values are controlled for Wechsler version used at first and (WISC-IV and WAIS-IV) and second assessment (WISC-IV and WAIS-IV). ADHD group: T1, n = 125, except for Processing Speed, n = 124; T2, n = 94. Control group: T1 n = 59; T2, n = 52; * = p < 0.05; ** = p < 0.01; *** = p < 0.001

TABLE 3.

Results for the predictors in relation to long-term outcomes for each of the Wechsler composites in separate linear mixed model analyses.

Dependent variable	Independent variables	Groups
		ADHD			Controls
		T1, n = 90, T2, n = 93			T1, n = 59, T2, n = 52
		Beta^a	95% CI	p−value	Beta^a	95% CI	p−value
FSIQ	Time (year)	−.93	−1.51 ;−.35	.002	1.10	.41 ; 1.79	.002
	Girls vs boys	4.10	−1.05 ; 9.25	.117	−1.37	−6.65 ; 3.91	.605
	WAIS vs WISC	3.11	−.86 ; 7.07	.119	−.71	−5.34 ; 3.92	.740
	Special education supports	−.95	−5.80 ; 3.89	.696	−9.25	−16.49 ; −2.02	.013
	SNAP IV T1, T2 ^b	−.08	−.23 ; .06	.250	−.04	−.54 ; .45	.861
	ADHD medication	1.55	−4.47 ; 7.56	.611
Verbal comprehension	Time (year)	−.92	−1.58 ;−.26	.007	2.13	1.19 ; 3.06	<.001
	Girls vs boys	4.39	−1.35 ; 10.12	.132	−3.75	−10.27 ; 2.77	.253
	WAIS vs WISC	−5.79	−10.31 ;−1.27	.014	−2.59	−8.78 ; 3.60	.374
	Special education supports	−3.26	−8.65 ; 2.13	.232	−6.71	−15.65 ; 2.22	.137
	SNAP IV T1, T2^b	−.02	−.18 ; .15	.821	.14	−.47 ; .75	.654
	ADHD medication	.50	−6.20 ; 7.19	.884
Perceptual reasoning	Time (year)	−.43	−1.07 ; .21	.184	.88	−.19 ; 1.94	.104
	Girls vs boys	1.73	−4.21 ; 7.68	.564	−5.61	−12.20 ; .98	.093
	WAIS vs WISC	.98	−3.43 ; 5.38	.653	−2.48	−9.45 ; 4.49	.446
	Special education supports	.29	−5.87 ; 5.30	.919	−7.45	−16.48 ; 1.58	.104
	SNAP IV T1, T2 ^b	.07	−.09 ; .23	.390	.02	−.60 ; .64	.954
	ADHD medication	1.94	−5.00 ; 8.89	.579
Working memory	Time (year)	−.28	−1.06 ; .50	.484	−.52	−1.45 ; .41	.268
	Girls vs boys	.77	−3.95 ; 5.49	.746	4.78	.45 ; 9.11	.031
	WAIS vs WISC	5.35	.30 ; 10.40	.039	3.59	−2.22 ; 9.40	.198
	Special education supports	−.48	−4.92 ; 3.95	.830	−4.06	−10.01 ; 1.88	.176
	SNAP IV T1, T2^b	−.23	−.41 ; −.06	.009	−.23	−.64 ;.17	.252
	ADHD medication	−.79	−6.28 ; 4.70	.775
Processing speed	Time (year)	−1.37	−2.21 ; −.53	.002	.30	−.86 ; 1.47	.602
	Girls vs boys	6.19	.70 ; 11.68	.028	3.36	−2.17 ; 8.89	.228
	WAIS vs WISC	10.51	4.98 ; 16.04	.001	.09	−7.18 ; 7.37	.978
	Special education supports	3.02	−2.14 ; 8.18	.248	−9.52	−17.11 ; −1.94	.015
	SNAP IV T1, T2 ^b	−.12	−.32 ; .07	.212	−.16	−.68 ; .36	.538
	ADHD medication	2.91	−3.48 ; 9.30	.369

1 Notes. ADHD = attention deficit hyperactivity disorder; 95% CI = 95% confidence interval; df = degrees of freedom; FSIQ = full scale intelligence quotient; SD = standard deviation; SNAP−IV = parent rated Swanson−Nolan−Pelham scale, version IV (ADHD-combined score); T1 = time 1 (baseline); T2 = time 2 (follow−up). a Beta values are unstandardized; b SNAP−IV was measured at T1 and T2 in the ADHD group, and at T1 in the Control group.

2 The Wechsler composite scores are measured in standardized composite scores, mean = 100, SD = 15

TABLE 4.

Results of logistic regression models of the relationship between the dependent variable grades at follow-up, and the independent variables parent rated SNAP-IV scores, and Wechsler composites in the ADHD group

Model statistics	Variables	Odds Ratio	95% CI	p-value
T1 Measures	SNAP-IV T1	.99	.94 ; 1.04	.678
Χ² = 5.86	Verbal comprehension	1.05	1.00 ; 1.10	.031
df = 5	Perceptual reasoning	.99	.96 ; 1.04	.788
p for model = .32	Working memory	.98	.94 ; 1.02	.335
Nagelkerke R² = .094	Processing speed	1.00	.97 ; 1.04	.815
n = 82
T2 Measures	SNAP-IV T2	.92	.87 ; .98	.007
Χ² = 23.80	Verbal comprehension	1.11	1.04 ; 1.19	.001
df = 5	Perceptual reasoning	1.01	.96 ; 1.07	.624
p for model < .001	Working memory	.95	.89 ; 1.00	.073
Nagelkerke R² = .356	Processing speed	1.00	.96 ; 1.04	.897
n = 79

1 Notes. 95% CI = 95% confidence interval; SNAP-IV = The Swanson-Nolan-Pelham scale. version IV (ADHD-combined score); T1 = time 1 (baseline); T2 = time 2 (follow-up)

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DOI: https://doi.org/10.21307/sjcapp-2021-007 | Journal eISSN: 2245-8875

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Language: English

Page range: 52 - 63

Published on: Apr 23, 2021

Published by: Center for Evidence-based Psychiatry

In partnership with: Paradigm Publishing Services

Publication frequency: 1 issue per year

Keywords:

ADHD,

children,

cognitive functioning,

follow-up study,

WISC,

school grades

Related subjects:

Medicine,

Basic medical science,

Basic medical science, other

© 2021 Pia Tallberg, Maria Rastam, Sean Perrin, Anne-Li Hallin, Peik Gustafsson, published by Center for Evidence-based Psychiatry
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 9 (2021): Issue 1 (January 2021)

A longitudinal investigation of cognitive functioning and its relationship to symptom severity and academic functioning in treatment seeking youth with ADHD

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