Table 1 Demographic, substance use, clinical, neuropsychological and brain characteristics

From: Hippocampal harms, protection and recovery following regular cannabis use

Group (n=111)

Controls (n=37)

Cannabis users (n=74)

Four-group comparisons a

Five-group comparisons b

  

CBDx (n=19)

CBD− (n=30)

CBD+ (n=12)

Former users (n=13)

F df

P

F df

P

Sample characteristics

 Male/female, %

49/51

47/53

43/57

58/42

85/15

6.713, 74

0.082c

6.974, 111

0.138c

 Age, years

29.95 (11.29)

34.26 (10.96)

32.10 (11.15)

31.67 (10.34)

38.69 (9.80)

1.313, 70

0.276

1.704, 106

0.156d

 Alcohol, standard drinks per month

19.9 (26.72)

25.96 (31.00)

26.41 (31.03)

8.69 (10.77)

41.62 (28.66)

2.843, 70

0.044

2.534, 106

0.044d

 Tobacco, cigarettes per week

5.18 (17.95)

48.18 (46.44)

66.97 (54.24)

63.42 (56.79)

24.65 (35.38)

2.403, 70

0.075

10.964, 106

<0.005d

 Anxiety symptoms

33.73 (7.58)

42.21 (11.71)

38.29 (11.40)

47.33 (12.42)

34.23 (12.49)

2.993, 70

0.037

5.014, 106

0.001d

 Depressive symptoms

12.17 (2.80)

15.53 (3.45)

13.80 (2.99)

15.50 (3.92)

12.92 (3.09)

2.393, 70

0.076

5.014, 106

0.001d

 Global functioning

86.76 (4.15)

69.58 (9.01)

76.93 (9.31)

70.67 (10.70)

78.15 (9.04)

3.683, 70

0.016

18.734, 106

<0.005d

 Intelligence quotient

112.32 (12.72)

103.68 (11.45)

103.17 (10.38)

101.26 (14.78)

109.93 (15.18)

1.243, 70

0.300

3.544, 106

0.009d

 Intracranial volume, mm3

1468.07 (141.02)

1459.49 (124.92)

1401.27 (153.69)

1447.79 (82.74)

1480.47 (121.31)

1.413, 70

0.246

1.324, 106

0.266

 Whole-brain volume, mm3

1251.02 (120.37)

1245.24 (107.23)

1196.91 (131.85)

1239.19 (69.22)

1257.65 (103.42)

1.243, 70

0.301

1.164, 106

0.333

Cannabis use measures

 Frequency, days per month

         

Lifetime

—

23.1 (7.11)

23.51 (6.78)

26.14 (4.68)

26.77 (8.39)

1.163, 70

0.333

—

 

Past 12 months

—

24.31 (9.13)

25.24 (8.8)

24.31 (8.80)

—

0.052, 58

0.954

—

 

 Dosage, joint cumulative

         

Lifetime

—

29,716 (3331)

20,739 (17,907)

27,385 (20,337)

13,151 (12,251)

8.253, 70

0.241

—

 

Past 12 months

—

1728 (1401)

1617 (1325)

1623 (917)

—

0.082, 58

0.920

  

 Duration, years

—

16.95 (9.24)

14.13 (9.53)

15.92 (10.37)

15.69 (9.23)

0.363, 70

0.783

  

 Onset age, years

—

17.08 (4.36)

16.97 (3.04)

15.58 (2.61)

18.31 (4.03)

1.233, 70

0.305

  

 THC levels in hair, ng mg−1e

—

—

0.18 (0.31)

0.27 (0.23)

—

−0.8633

0.394

  

 CBD levels in hair, ng mg−1e

—

—

—

0.02 (0.01)

—

    
  1. Abbreviations: CBD, cannabidiol; THC, Δ9-tetrahydrocannabinol.
  2. All values presented in mean (s.d.).
  3. aAnalyses (two tailed) comparing CBDx (those testing positive for urinary cannabinoid metabolites), CBD− (those exposed to THC but not to CBD), CBD+ (those exposed to both THC and CBD) and Former User (former regular users who were abstinent for a prolonged period) groups.
  4. bAnalyses (two tailed) comparing controls, CBDx, CBD−, CBD+ and Former User groups.
  5. cχ2-test.
  6. dVariables used as covariates in all statistical analyses of variance.
  7. eHair sample analysis (t-test) was available only for CBD−, CBD+ and Former User groups. Anxiety (trait) assessed by the State and Trait Anxiety Inventory; depressive symptoms assessed by the Community Assessment of Psychic Experiences; global functioning assessed by the Social and Occupational Functioning Assessment Scale; intelligence assessed using the Wechsler Abbreviated Scale of Intelligence (WASI); and cannabis use patterns assessed by structured interview and Timeline Follow-back Procedures to estimate average lifetime frequency of use (since age of regular use initiation) and cumulative dosage (since first initiation of cannabis), duration of regular use and age of regular cannabis use initiation.
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