Scientific study reveals: Genetic risks behind cannabis abuse
In one study which included genetic data of more than a million people, scientists began to discover it the genetics of cannabis addiction.
Scientists have identified genetic variants associated with the risk of developing cannabis abuse, a condition in which people build a tolerance to the substance and struggle to reduce use despite the negative effects on life and health. "Live Science" (Live Science).
This disorder has official diagnostic criteria in the Handbook of Mental Health Disorders, but, roughly speaking, it means cannabis use that becomes problematic and includes tolerance or other biological signs of addiction, such as a withdrawal crisis.
In order to examine the potential genetic risks of the disorder, the researchers analyzed the genomes of more than a million people, of whom about 64.000 had been diagnosed with cannabis addiction, mostly people from Europe, but also from Africa, East Asia and of mixed descent.
In each population, key sites of genetic variation in the genome associated with cannabis addiction have been identified. Twenty-two "sites" relevant to Europeans were found, two each in Africans and East Asians, and one each in people of mixed ancestry.
Therefore, it is important to expand genomic research beyond the area of European ancestry in order to discover more gene variants that are relevant to each population.
In the new study, published Nov. 20 in the journal Nature Genetics, hot spots of variation often appear near genes associated with neurons, cells of the nervous system that communicate with electrical and chemical messages. This included a gene encoding a dopamine receptor essential in the brain's reward system and with a role in addiction.
- Other types of neurons that respond to different chemical messages also appeared in the data. However, cannabis receptors did not jump to the highest level. It is possible that genes associated with cannabis receptors will appear in larger datasets. So far, most of what we've seen is downstream of the direct interaction of cannabis constituents with receptors in the brain, the researchers say.
In addition to identifying hotspots, it was examined whether these genetic characteristics co-occur with those associated with other disorders and behaviors. The links between cannabis abuse and cigarette smoking, various forms of addiction and symptoms of post-traumatic stress disorder (PTSD) have been discovered.
The researchers compared genetic patterns associated with cannabis addiction to patterns previously associated with general cannabis use. The patterns were quite different – general cannabis use was not associated, for example, with (PTSD). However, both general cannabis use and diagnosed disorder were associated with schizophrenia, although in the latter case the association was stronger.
Finally, a potential genetic link between cannabis addiction and lung cancer has been discovered. Smoking cannabis contains combustion products that could be the mechanism of the lung cancer link, and we have seen that cannabis addiction is also linked to cigarette smoking, a known cause of lung cancer. In the study, cannabis addiction remained associated with lung cancer even when cigarettes were eliminated from the mix.