Sociodemographic characteristics of the participants.

<p>Asterisk indicates significant difference between cannabis dependent and controls subjects. SD  =  Standard deviation.</p>*<p>p<0.05;</p>***<p>p<0.001.</p

Genotype distributions in cannabis dependent subjects and controls for the SNPs studied.

<p>N = 100, except for PENK rs2576573 for which 5 subjects were excluded due to genotyping failure. Asterisks indicate a significant SNP x group (cannabis dependence diagnosis vs. control) effect.</p>*<p>p<0.05,</p>**<p>p<0.01,</p>***<p>p<0.001, uncorrected.</p

DRD2 SNP rs6277 in relation to the accuracy of choose A (positive reinforcement) and Avoid B (negative reinforcement) performance.

<p>***, p<0.005 between the genotypes.</p

Figure 3

<p>High risk genotype  = C/C + C/T for rs2609997 or A/A + A/G for rs2576573; low risk genotype  = T/T for rs2609997 or G/G for rs2576573. ***p<0.01; ****p<0.001.</p

Sociodemographic characteristics and genotype distribution for the proenkephalin SNPs studied in the Caucasian Greek cohort.

<p>All subjects were healthy control males from a highly homogenous Caucasian population of army conscripts. Minor allele frequency was 0.44 (rs2576573) and 0.46 (rs2609997). Hardy-Weinberg equilibrium for the full population: χ² = 3.2 (p = 0.07) rs2576573 and 1.8 (p = 0.18) for rs2609997. SD: standard deviation.</p>#<p>one non-smoker with missing genotype;</p>##<p>one smoker and two non-smokers with missing genotype.</p

Neuroticism scores in relation to PENK rs2609997 SNP among controls, and in cannabis-dependent subjects.

<p>*, p<0.05 between the genotypes.</p

Neuroticism score in relation to SNPs studied.

<p>Neuroticism score in relation to SNPs studied.</p

Baseline prevalence (%) of distressing somatic symptoms in past 7 days by sex and age.

<p>Baseline prevalence (%) of distressing somatic symptoms in past 7 days by sex and age.</p

Specification and recruitment of study sample.

<p>Specification and recruitment of study sample.</p

Adverse health beliefs regarding low back and arm pain – prevalence (%) by occupational group.

a<p>Completely agree that such pain is commonly caused by people’s work.</p>b<p>Completely agree that for someone with such pain, a) physical activity should be avoided as it might cause harm, and b) rest is needed to get better.</p>c<p>Completely agree that for someone with such pain, rest is needed to get better, and completely disagree that such problems usually get better within three months.</p