Table 1 |.
Main phenotypes related to SUDs investigated in the largest genome-wide association studies available
| SUD outcome | Description | GWS loci | SNP-based heritability | Sample size | Refs |
|---|---|---|---|---|---|
| Alcohol | |||||
| Alcohol dependence | Alcohol dependence (AD) diagnosis based on DSM-IV or DSM-III-R criteria | 1 | 0.090±0.019 | 14,904/37,944 | 8 |
| Alcohol use disorder | AUD diagnosis based on ICD-9 and ICD-10 codes | 10 | 0.056±0.004 | 55,584 /218,807 | 14 |
| Problematic alcohol use | Meta-analysis of cohorts assessed using different phenotypic definitions including AD, AUD, and AUDIT-P | 42 | 0.068±0.004 | 300,789* | 13 |
| Alcohol use disorder identification test:consumption | AUDIT-C scores were derived from electronic health records | 13 | 0.068±0.005 | 272,842 | 14 |
| Drinks per week | Average number of standard drinks a subject reports consuming each week | 99 | 0.042±0.002 | 941,280 | 15 |
| Tobacco smoking | |||||
| Nicotine dependence | Nicotine dependence category (mild, moderate, severe) defined on the basis of the Fagerström Test for Nicotine Dependence (FTND) scores | 5 | 0.086±0.012 | 58,000 | 185 |
| Age of initiation of regular smoking | The age at which an individual first became a regular smoker | 10 | 0.047±0.003 | 341,427 | 15 |
| Cigarettes per day | Average number of cigarettes smoked per day binned in categories | 55 | 0.08±0.008 | 337,334 | 15 |
| Smoking initiation | Binary phenotype with ever regular smokers coded as cases and never regular smokers coded as controls | 378 | 0.078±0.002 | 557,337/ 674,754 | 15 |
| Smoking cessation | Binary phenotype with current smokers coded as cases and former smokers coded as controls | 24 | 0.046±0.002 | 139,453/407,766 | 15 |
| Smoking trajectories | Longitudinal trajectory groups for smoking status based on electronic health records | 20 | 0.187±0.01 0.058±0.005 |
286,118 | 28 |
| Opioids | |||||
| Opioid dependence | Opioid dependence (OD) diagnosis based on DSM-IV criteria. Opioid exposure defined as being exposed to opioids at least once | 0/1 | NS 0.28±0.1 |
4,503/4,173/32,500 | 41 |
| Opioid use disorder | OUD diagnosis and opioid exposure based on ICD-9 and ICD-10 codes | 1 | 0.113±0.018 | 15,756/99,039 | 44 |
| Opioid exposure | Opioid exposure defined as being exposed to opioids at least once | 1 | NS | 4,173/32,500 | 41 |
| Cannabis | |||||
| Cannabis use | Self-reported information on whether the participants had ever used cannabis during their lifetimes | 8 | 0.11±0.01 | 180,934* | 34 |
| Cannabis use disorder | CUD diagnosis based on DSM-IV or DSM-III-R criteria or ICD-10 codes | 2 | 0.067±0.006 | 20,916/363,116 | 37 |
| Age at first cannabis use | Age at first cannabis use assessed from questionnaires or clinical interviews | 5 | NS | 24,953 | 35 |
| Cocaine | |||||
| Cocaine dependence | DSM-IV symptom count for cocaine dependence DSM-IV cocaine dependence diagnosis |
1/0 | NA 0.30±0.06 |
9,760 2,085/4,293 |
46,47 |
For each trait, we report a brief description, the number of genome-wide significant (GWS) loci, the SNP-based heritability, and the sample size. For binary traits, we reported the number of cases and controls (i.e., cases/controls). For traits meta-analysing different types of phenotypic definitions, we reported the effective sample size (*). For smoking trajectories, we report the SNP-based heritability calculated for contrast I (current versus never) and contrast II (current versus mixed). With respect to opioid dependence, the case–control analysis was conducted considering opioid-exposed controls and opioid-unexposed controls separately. For this phenotype, we reported information (i.e., GWS loci, SNP-based heritability, and sample size) for both analyses (cases/opioid-exposed controls/opioid-unexposed controls). With respect to cocaine dependence, we reported results from two studies. AUD, alcohol use disorder; AUDIT, Alcohol Use Disorders Identification Test for consumption (AUDIT-C) or problems (AUDIT-P); CUD, cannabis use disorder; DSM, Diagnostic and Statistical Manual of Mental Disorders; ICD, International Classification of Diseases; NA, not available in the referenced publication; NS, not significant (p>0.05); SUD, substance use disorder.