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 comparisonsaFive-group comparisonsb
  CBDx (n=19)CBD− (n=30)CBD+ (n=12)Former users (n=13)FdfPFdfP
Sample characteristics
 Male/female, %49/5147/5343/5758/4285/156.713, 740.082c6.974, 1110.138c
 Age, years29.95 (11.29)34.26 (10.96)32.10 (11.15)31.67 (10.34)38.69 (9.80)1.313, 700.2761.704, 1060.156d
 Alcohol, standard drinks per month19.9 (26.72)25.96 (31.00)26.41 (31.03)8.69 (10.77)41.62 (28.66)2.843, 700.0442.534, 1060.044d
 Tobacco, cigarettes per week5.18 (17.95)48.18 (46.44)66.97 (54.24)63.42 (56.79)24.65 (35.38)2.403, 700.07510.964, 106<0.005d
 Anxiety symptoms33.73 (7.58)42.21 (11.71)38.29 (11.40)47.33 (12.42)34.23 (12.49)2.993, 700.0375.014, 1060.001d
 Depressive symptoms12.17 (2.80)15.53 (3.45)13.80 (2.99)15.50 (3.92)12.92 (3.09)2.393, 700.0765.014, 1060.001d
 Global functioning86.76 (4.15)69.58 (9.01)76.93 (9.31)70.67 (10.70)78.15 (9.04)3.683, 700.01618.734, 106<0.005d
 Intelligence quotient112.32 (12.72)103.68 (11.45)103.17 (10.38)101.26 (14.78)109.93 (15.18)1.243, 700.3003.544, 1060.009d
 Intracranial volume, mm31468.07 (141.02)1459.49 (124.92)1401.27 (153.69)1447.79 (82.74)1480.47 (121.31)1.413, 700.2461.324, 1060.266
 Whole-brain volume, mm31251.02 (120.37)1245.24 (107.23)1196.91 (131.85)1239.19 (69.22)1257.65 (103.42)1.243, 700.3011.164, 1060.333
          
Cannabis use measures
 Frequency, days per month         
  Lifetime23.1 (7.11)23.51 (6.78)26.14 (4.68)26.77 (8.39)1.163, 700.333 
  Past 12 months24.31 (9.13)25.24 (8.8)24.31 (8.80)0.052, 580.954 
 Dosage, joint cumulative         
  Lifetime29,716 (3331)20,739 (17,907)27,385 (20,337)13,151 (12,251)8.253, 700.241 
  Past 12 months1728 (1401)1617 (1325)1623 (917)0.082, 580.920  
 Duration, years16.95 (9.24)14.13 (9.53)15.92 (10.37)15.69 (9.23)0.363, 700.783  
 Onset age, years17.08 (4.36)16.97 (3.04)15.58 (2.61)18.31 (4.03)1.233, 700.305  
 THC levels in hair, ng mg−1e0.18 (0.31)0.27 (0.23)−0.86330.394  
 CBD levels in hair, ng mg−1e0.02 (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.