Karl Marx once defined religion as “the opiate of the masses.” It turns out this statement rings true both in politics and in pharmacology. It is rather hard to dispute the proposition that mankind’s history is embedded with religion, but recently we have developed the necessary scientific mechanisms to analyze the physical origins and nature of this aspect of the human experience.

Recent studies, some of which have been conducted at the Department of Clinical Neuroscience in the Karolinska Institute of Sweden, demonstrate that religious experiences often trigger the release of neurotransmitters like dopamine. These stimulate regions of the brain that regulate reward mechanisms. In other words, in terms of physiology, religion functions like a drug, setting off the same pleasurable signals to your brain that you may feel when you are high on cocaine or heroin. Religion, therefore, can lead to a behavioral addiction, which may account for the close attachment millions on the planet have towards their particular faith, whatever it may be.

Though the science behind this study may be relatively new, free thinkers and intellectuals have long foreseen a connection between religion and drugs. In the essay “Doors of Perception and Heaven and Hell,” English writer Aldous Huxley famously hypothesized that the hallucinogenic effects induced by chemicals like LSD and other psychoactive drugs unlock “doors of perception,” from which all spiritual experiences originate. Huxley further argues that amazing artistic or musical accomplishments inspired by religion are like psychedelically-induced phenomena caused by the use of hallucinogens. Not surprisingly, other thinkers have gone as far as to suggest the fathers of humanity’s largest religions—such as Jesus or Mohammed—were actually “inspired” by stimulants around them, thus experiencing revelations that contributed to the creation of doctrines that influence billions today.

On a more realistic level, though, it can be argued that religion has evolved on the basis of the biological principle behind a reward system. Some believers don’t place primary importance on actual doctrine and theological details. In fact, the most common justification for a person’s faith is his or her “personal relationship with God,” experienced in places of worship among fellow believers. Many churchgoers may also notice that religious experience is enhanced by a sense of unanimity in large numbers. This is a common example of in-group favoritism that is also found in other areas such as ideology, partisanship, or team sports.

It is important to note, however, that by no means do these discoveries  undermine the utility and resourcefulness of faith. The organizing, regulatory, and social natures of religion, as some researchers argue, have led to an increase in respect, morality, and order within communities. Without religion, it is hard to fathom how our ancestors would have maintained order inside growing populations.

Sources: bigthink.com, neuroresearchproject.com, economist.com, The Doors of Perception by Aldous Huxley