Gambling frequency and symptoms of attention-deficit hyperactivity disorder in relation to problem gambling among Swedish adolescents: a population-based study

Figures & data

Figure 1. Flow chart of the study population. Administrative drop-out refers to students from classes or schools that did not participate in SALVe 2012. External non-respondents are students who were absent on the day of data collection and did not return their questionnaire by mail or who declined to participate. Those who did not sufficiently complete the questions for the present study were referred to as ‘internal non-respondents’.

Table 1. Descriptive statistics for the sample of adolescents aged 15–18 years.

	Total	Boys	Girls
	n (%)	n (%)	n (%)	Chi-square	p
Age
15–16 years	2011 (45.3%)	997 (45.6%)	1014 (45.0%)
17–18 years	2429 (57.7%)	1189 (54.4%)	1240 (55.0%)	0.173	0.677
Ethnicity
Scandinavian	3434 (78.6%)	1654 (77.3%)	1780 (79.8%)
Non-Scandinavian	937 (21.4%)	487 (22.7%)	450 (20.2%)	4.274	0.039
Parental living condition
Parents living together	2802 (63.3%)	1413 (65.0%)	1389 (61.7%)
Parents not living together	1622 (36.7%)	761 (35.0%)	861 (38.3%)	5.067	0.024
Parental working status
Both parents employed	3582 (81.4%)	1774 (82.1%)	1808 (80.6%)
At least one parent unemployed	821 (18.6%)	387 (17.9%)	434 (19.4%)	1.524	0.217
Symptoms of ADHD
No symptoms of ADHD	3605 (81.2%)	1819 (83.2%)	1786 (79.2%)
Symptoms of ADHD	835 (18.8%)	367 (16.8%)	468 (20.8%)	11.480	<0.001
Online gambling frequency
Never	3834 (90.2%)	1714 (82.6%)	2120 (97.5%)
A few times a year	164 (3.9%)	138 (6.7%)	26 (1.2%)
Once a month	88 (2.1%)	77 (3.7%)	11 (0.5%)
2–4 times a month	76 (1.8%)	65 (3.1%)	11 (0.5%)
2–3 days a week	31 (0.7%)	28 (1.4%)	3 (0.1%)
4–5 days a week	21 (0.5%)	20 (1.0%)	1 (0.0%)
6–7 days a week	35 (0.8%)	32 (1.5%)	3 (0.5%)	266.480	<0.001
Offline poker gambling frequency
Never	3887 (89.2%)	1734 (81.4%)	2153 (96.6%)
A few times a year	305 (7.0%)	248 (11.6%)	57 (2.6%)
Once a month	84 (1.9%)	77 (3.6%)	7 (0.3%)
2–4 times a month	44 (1.0%)	36 (1.7%)	8 (0.4%)
2–3 days a week	20 (0.5%)	17 (0.8%)	3 (0.1%)
4–5 days a week	7 (0.2%)	7 (0.3%)	0 (0.0%)
6–7 days a week	12 (0.3%)	12 (0.6%)	0 (0.0%)	267.702	<0.001
Offline gambling frequency on the lottery or other games
Never	3159 (72.4%)	1459 (68.4%)	1700 (76.1%)
A few times a year	789 (18.1%)	348 (16.3%)	441 (19.7%)
Once a month	207 (4.7%)	141 (6.6%)	66 (3.0%)
2–4 times a month	105 (2.4%)	89 (4.2%)	16 (0.7%)
2–3 days a week	70 (1.6%)	62 (2.9%)	8 (0.4%)
4–5 days a week	19 (0.4%)	17 (0.8%)	2 (0.1%)
6–7 days a week	17 (0.4%)	17 (0.8%)	0 (0.0%)	175.575	<0.001
Offline gambling frequency on slot machines
Never	3664 (84.1%)	1677 (78.8%)	1987 (89.1%)
A few times a year	554 (12.7%)	331 (15.6%)	223 (10.0%)
Once a month	67 (1.5%)	56 (2.6%)	11 (0.5%)
2–4 times a month	31 (0.7%)	28 (90.3%)	3 (0.1%)
2–3 days a week	17 (0.4%)	13 (1.3%)	4 (0.2%)
4–5 days a week	9 (0.2%)	8 (0.4%)	1 (0.0%)
6–7 days a week	14 (0.3%)	14 (0.7%)	0 (0.0%)	119.554	<0.001
Problem Gambling Severity Index
No risk/low risk of problem gambling (0–2 points)	1222 (86.5%)	763 (81.6%)	459 (96.2%)
Moderate risk of problem gambling (3–7 points)	117 (8.3%)	106 (11.3%)	11 (2.3%)
High risk of problem gambling (8 points)	73 (5.2%)	66 (7.1%)	7 (1.5%)	57.992	<0.001

Table 2. Kendall’s Tau (and Cramer’s V for sex) correlations between study variables.

		Total population (n = 4440)					Gambling population (n = 1412)
Factors	1	2	3	4	5	6	7	8
1. Sex	1	0.144***	0.250***	0.248***	0.201***	0.166***	0.353***	0.250***
2. Symptoms of ADHD		1	0.040**	0.043**	0.035**	0.065**	0.050**	0.134**
3. Online gambling frequency			1	0.508**	0.310**	0.302**	0.503**	0.417**
4. Offline poker gambling frequency				1	0.351**	0.365**	0.534**	0.424**
5. Offline gambling frequency on the lottery or other games					1	0.334**	0.721**	0.341**
6. Offline gambling frequency on slot machines						1	0.592**	0.369**
7. Gambling frequency index							1	0.431**
8. Problem gambling								1

** p < 0.01 level (2-tailed); *** p < 0.001 level (2-tailed).

Table 3. Zero-inflated negative binomial regression analysis, adjusted for an excess of zero values for associations between investigated variables; dependent variable: PGSI.

Model I. Analysis of the chance of not becoming susceptible to developing gambling problems.^a
	OR	p	95% CI
Age	0.48	0.001	0.30	0.75
ADHD symptoms index	0.95	0.041	0.90	1.00
Gambling frequency index	0.46	0.009	0.26	0.82
ADHD symptoms × Gambling frequency index	0.92	0.023	0.85	0.99
Model II. Analysis of adolescents already susceptible to problem gambling.^b
	IRR	p	95% CI
ADHD symptoms index	1.03	0.031	1.003	1.07
Gambling frequency index	1.34	<0.001	1.20	1.51
Sex (ref: boys)	0.25	<0.001	0.16	0.38
Sex × Gambling frequency index	1.67	<0.001	1.34	2.13

^a Model I: adjusted for covariates sex and parents’ country of birth.

^b Model II: adjusted for covariate age.

Figure 2. Illustration of the association between gambling frequency and the Problem Gambling Severity Index (PGSI). The expected degree of gambling problems in the study sample, irrespective of susceptibility to gambling problems, plotted against gambling frequency for different degrees of ADHD symptoms according to the ADHD symptom index.