TABLE 2.

Substance use characteristics.

Group (n = 84)	Controls (n = 27)	Cannabis users (n = 27)	Polydrug users (n = 30)
Alcohol, standard drinks per week,%
0	3.7	0	0
<1	44.4	48.2	43.3
1–3	37	48.2	33.3
4–6	14.8	3.7	20
7–14	0	0	3.3
14<	0	0	0
Tobacco, %
No	74.1	44.4	56.7
Occasionally	25.9	40.7	26.7
Regullary	0	14.8	16.7
Cannabis use pattern
Onset age, years mean	—	21.4 ± 4.68	19.7 ± 3.25
Duration, years mean (SD)	—	9.04 ± 7.09	8.28 ± 4.46
Frequency of cannabis use (% of subjects) lifetime
0	81.5	3.7	6.7
Less than twice a year	18.5	0	3.3
2–3 times per month	0	0	6.7
1–3 times per week	0	29.6	23.3
3–6 times per week	0	37	23.3
Daily	0	29.6	36.7
No answer	0	0	0
Frequency of cannabis use within past 30 days
0	100	7.4	10
2–3 times per month	0	7.4	3.33
1–3 times per week	0	29.6	23.3
3–6 times per week	0	33.3	33.3
Daily	0	18.5	30
Dose in puffs per one use mean (SD)		7.42 ± 3.05	7.38 ± 2.7
Dose in grams per week (%)
Less than 1 g	0	38.5	28.6
1–2 grams	0	38.5	21.4
3–5 grams	0	23.1	39.3
>5 grams	0	0	10.7
Time since last cannabis use (%)
<12 h	0	7.7	7.1
12–24 h	0	46.2	57.1
1–3 days	0	15.4	25
3–7 days	0	19.2	7.1
7–14 days	0	3.9	0
>14 days ago	0	7.7	3.6
Other illicit drug use in last 30 days (% of subjects)
0	100	100	60
1 time per month	0	0	33.3
2 ≤ per month	0	0	6.7

It is important to note that the ordinal data on substance use are presented in table in percentages, however, during analyses (while performing series of Mann–Whitney U or Kruskal–Wallis H tests) they were coded numerically.