Genetic Discovery Provides Explanation for Cannabis Use, Schizophrenia Connection

Many individuals try cannabis and soon develop dependence. However, as with many substances, some individuals are able to use the drug without developing an abuse problem. The increased vulnerability of some when it comes to drug use is tied to various factors, both biological and environmental.

However, experts have long believed that there is a genetic component to cannabis dependence. Despite environmental influences, there is likely a genetic factor that makes some people more likely to develop an addiction to the drug.

To test the role of a particular gene in cannabis dependence, Shizhong Han and colleagues examined the gene NRG1, which codes for the ErbB4 receptor. The receptor is a protein that plays an important part in synaptic development and function.

The study’s findings are published in a recent issue of Biological Psychiatry and finds that the NRG1 is important in the development of increased risk for cannabis dependence.

The researchers used a multi-stage design to draw from genetic data including African American and European American groups of families. First, the researchers conducted an analysis of the linkage, locating a signal on chromosome 8p21 in African Americans.

Through a genome-wide association study dataset, the researchers then centered in on NRG1, which consistently exhibited associations in both European Americans and African Americans. Finally, the association of the variant was tested as an independent sample in the group of African American families.

With the total findings taken together, the study provides evidence that NRG1 may be a cannabis dependence susceptibility gene.

Along with this unprecedented discovery, the researcher also notes that within the findings there may also be a connection between susceptibility for cannabis dependence and schizophrenia.

NRG1 was first in the news when it was identified through several studies as a heritable risk for the development of schizophrenia. In addition, other research has shown that in post-mortem brain analysis, the regulation of NRG1 is altered in those who have schizophrenia.

The new findings may improve the understanding of the connection between cannabis use and the risk of developing schizophrenia. The existing body of research often supports the explanation of the connection as schizophrenia resulting from cannabis use.

However, the current study lends creditability to the understanding of cannabis dependence and schizophrenia co-morbidity as a common genetic link between the two disorders.

Further research is needed to fully understand the connection between cannabis dependence and schizophrenia, and the role of genetics in contributing to both.

The contribution of NRG1 in cannabis dependence and schizophrenia may not only lead to better understanding, but also to new developments in addressing the needs of those struggling with either condition. The study may act as a springboard for new ideas for education, intervention and treatment.