Collecting large scale samples is difficult for substance use disorders such as heroin addiction; nonetheless, in order to achieve robust results, whether at the SNP level, gene or pathway level, a substantially larger sample size, in the range of tens of thousands of individuals, is required. Acknowledging this need, the Psychiatric Genetics Consortium (PGC) for Substance Use Disorders has been set up and data from the current study has been offered to the PGC-SUD, which is collecting data from other GWAS studies on substance use. The large number of samples will achieve the level of statistical power required and will provide much needed information on the etiological basis of opioid dependence. In conclusion, we have presented the results of the first genome wide study of heroin dependence in a Chinese sample, identifying novel associations between addiction and variation within genes that will be tested for replication in a large collaborative effort.
