Behavior Genetics Association 39th Annual Meeting Abstracts

Abstract

In the conceptualization of the revisions to the substance use disorders section for DSM-V, one action item has emerged as vital: the exclusion of a cannabis withdrawal syndrome in DSM-IV. There is now overwhelming evidence supporting the existence of a cannabis withdrawal syndrome, from both laboratory studies and epidemiological investigations. Item response analyses also demonstrate that the criterion of cannabis withdrawal in general population settings exhibits high difficulty but also superior discrimination making it a criterion that might help distinguish affected individuals at a higher end of the liability continuum. Despite this growing urgency for inclusion of a cannabis withdrawal syndrome in DSM-V, relatively little is known of the role of familial influences on cannabis withdrawal and whether it enhances the magnitude of familial variance in the composite cannabis use disorders measure. Using data on large multiplex families ascertained primarily for alcoholism and corresponding control individuals, both part of the Collaborative Study on the Genetics of Alcoholism (COGA, N = 3097 individuals reporting 21 or more instances of cannabis use in a single year), we (a) examine familial correlations between 7 individual withdrawal items (irritability, trouble sleeping, trembling, sweat/fever, nausea, gastrointestinal problems and appetite change) and the putative cannabis withdrawal criterion for DSM-V; (b) conduct item response modeling to investigate the utility of the addition of the cannabis withdrawal syndrome to the existing measure of cannabis use disorders; and (c) investigate preliminary evidence for criterion-specific familial influences on the withdrawal syndrome. Models were fit in MPlus (v5). Thirty-one percent of the COGA participants who had used cannabis 21? times in a single year endorsed 1 or more cannabis withdrawal symptoms-the most commonly endorsed symptom was experiencing tension, nervousness, restlessness and/or irritability (24.5%). Inclusion of withdrawal as a criterion increased the prevalence of cannabis dependence (without clustering) from 38.3% to 39.8%. Sibling and parent-offspring correlations for endorsing any 1 symptom were 0.27 and 0.18, respectively. Underlying the 7 withdrawal items was a single factor (loadings ranging from 0.39 to 0.69). Furthermore, underlying the 3 DSM-IV abuse (excluding legal problems) and 6 DSM-IV dependence criteria (excluding withdrawal) was a liability continuum-withdrawal (each of the 7 items; endorsing 1 symptom; relief from 3 or more symptoms) loaded well (0.88-0.93) on this underlying continuum and provided increased measurement precision. Using multiple indicator multiple causes (MIMIC) modeling, we found that after accounting for sibling similarity for cannabis use disorders, there was no evidence for an additional association between proband and sibling withdrawal. The current analyses suggest that cannabis withdrawal is integral to the assessment of cannabis use disorders. In this sample of dense, multiplex families, cannabis withdra...