Our results must be weighed with respect to the study’s strengths and limitations. One important limitation of our analyses is the population sampled – entering college students at a competitive university. Individuals who exhibited more extreme externalizing behavior – thus disrupting academic performance in adolescence – were less likely to be present in our sample. However, our results independently extend previous results with this gene set found in the COGA sample, which was specifically selected for family history of alcohol use disorders. The consistency of results across samples with different potential sources of selection bias increases confidence in the robustness of the enrichment findings. Next, the set of SNPs available for analyses were limited to those that were present on the specific chip platform used in the current study and that passed quality control filters. Thus, nine genes from the original set could not be included, nor could potential rare causal variants not present on the chip. The personality measures were only available at five of the eleven waves and by the final wave, data was missing on a majority
