Linkage analyses of cannabis “craving” e.g. endorsing: “In situations where you couldn't use marijuana, did you ever have such a strong desire for it that you couldn't think of anything else” and the cannabis withdrawal symptom of: “Did stopping or cutting down after a period of regular use of marijuana ever cause you to feel nervous, tense, restless or irritable” revealed 5 sites with LOD scores over 3.0. The symptom of cannabis craving yielded the strongest evidence for linkage (LOD = 5.7) on chromosome 7 between 70 and 83 cM with a peak at 79 cM. At that same site there was suggestive evidence of linkage within that same support interval with a peak at 71 cM for the withdrawal phenotype (LOD = 2.2) as illustrated in Figure 2.
