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. Author manuscript; available in PMC: 2021 Jun 7.
Published in final edited form as: Psychol Med. 2015 Mar 2;45(11):2275–2284. doi: 10.1017/S0033291715000227

Table 3.

Rates and patterns of cannabis use over lifetime by group

Cannabis scale CHR (n = 732) Controls (n = 276) Statistics p
Mean age first tried, years (s.d)a 15.7 (2.82) 16.6 (2.71) t = 2.86 0.004
Mean number of times used in lifetime (s.d.)b 125.5 (124.90) 63.0 (100.15) t = 4.82 <0.001
Ever smoked/used, yes 404 (55.2) 110 (39.9) χ2 = 18.98 <0.001
 Currently using 238 (32.4) 81 (29.1) χ2 = 9.29 <0.01
 Past use only 164 (22.3) 27 (9.7)
 Missing 333 (45.3) 170 (61.2)
Use frequency for current users
 Every day 21 (2.9) 2 (0.7) χ2 = 9.50 0.22
 Once/twice per week 78 (10.6) 10 (3.6)
 Once/twice per month to once/twice per year 79 (10.7) 23 (8.3)
 Not applicable 126 (17.1) 35 (12.6)
 Missing 431 (58.7) 208 (74.8)
Environment for current users
 Socially 324 (44.1) 100 (36.0) χ2 = 11.01 0.001
 Alone 64 (8.7) 4 (1.4)
 Missing 347 (47.2) 174 (62.6)
Time of use for current users
 During the day 48 (6.5) 4 (1.4) χ2 = 19.21 <0.001
 During the evening 212 (28.8) 80 (28.8)
 Frequently during the day and evening 141 (19.2) 21 (7.6)
 Missing 334 (45.4) 173 (62.2)

Data are given as number of participants (percentage) unless otherwise indicated.

CHR, Clinical high risk; s.d., standard deviation.

a

Excludes participants who had never used cannabis.

b

Excludes never-users.