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. 2016 Feb 15;18(2):e36. doi: 10.2196/jmir.4752

Table 5.

Gambling variables changes at 12 weeks by intervention group (n=1122).

Gambling variables (last 30 days) Minimum Median Maximum Mean (SD) or n (%) P value within the group
Deposit in €

Waiting list -5180.00 0.00 3000.00 -17.67 (573.55) .03

Feedback email -12800.00 -3.00 2150.00 -136.69 (884.45) <.001

Self-help CBT book -4058.00 -10.00 9300.00 -33.41 (801.36) <.001

Weekly emailed CBT -2600.00 -10.00 2710.00 -54.22 (365.61) <.001
Total loss in € a

Waiting list -4990.51 2.31 8333.44 -3.30 (852.54) .12

Feedback email -2315.58 0.68 26580.10 193.78 (1792.40) .10

Self-help CBT book -4051.70 8.00 181410.22 737.06 (11252.29) .02

Weekly emailed CBT -2304.00 2.00 10348.32 63.47 (803.72) .14
Mean loss per gambling session a

Waiting list -1062.72 0.00b 176.63 -5.64 (70.02) .9

Feedback email -87.89 0.01 227.21 0.68 (19.09) .5

Self-help CBT book -134.81 0.08 3003.66 11.90 (187.26) .2

Weekly emailed CBT -73.15 0.03 96.21 0.72 (14.10) .3
Total stake in €

Waiting list -20160.14 -63.50 90062.29 143.79 (6345.74) .007

Feedback email -54205.38 -33.21 26282.27 -318.87 (4284.30) .002

Self-help CBT book -62492.55 -36.84 50231.28 -5.36 (7083.45) .003

Weekly emailed CBT -20276.97 -46.50 122346.52 576.16 (8490.70) <.001
Number of gambling sessions

Waiting list -448.00 -7.00 285.00 -11.91 (71.56) .005

Feedback email -262.00 -8.00 318.00 -5.25 (66.27) <.001

Self-help CBT book -381.00 -6.00 356.00 -8.96 (71.42) .001

Weekly emailed CBT -501.00 -8.00 365.00 -6.46 (71.46) .002
Multitabling, yes (%)

Waiting list


-18% <.001

Feedback email


-13% <.001

Self-help CBT book


-18% <.001

Weekly emailed CBT


-17% <.001
Compulsivity, yes (%)

Waiting list


0.0% 1

Feedback email


-3.1% .07

Self-help CBT book


-0.8% .7

Weekly emailed CBT


1.7% .3
PGSI

Waiting list (n=45) -10.00 -3.00 0.00 1.00 (12.00) .02

Feedback email (n=41) -14.00 -3.00 -1.00 0.00 (6.0) <.001

Self-help CBT book (n=19) -9.00 -4.00 -3.00 0.00 (7.0) .09

Weekly emailed CBT (n=8) -8.00 -2.50 -1.00 0.50 (5.0) .4

aA negative value is a worsening, and a positive value is an improvement for the participant.

bAs the variance is huge on the monetary variables, median is more meaningful than the mean.