LSD Blurs the Boundaries Between the Self and Others, New Study Finds

Users of psychedelic drugs such as LSD often report feelings of unity and interconnectedness with others when describing their experiences.

Now, a new study published in the journal JNeurosci, has found that LSD (lysergic acid diethylamide) blurs the mental boundaries between the experiences of ourselves and and others. The drug alters brain activity in regions which are responsible for differentiating between where your own self stops and another person begins.

The latest findings could lead to the development of new treatments for mental disorders such as depression or schizophrenia. People suffering from these conditions usually have difficulties with interpersonal relationships and distort their experiences, which can negatively impact the progression of their diseases.

To date, very little research has been conducted into the neurobiological mechanisms behind these disorders—something the scientists wanted to address.

Researchers from the University of Zurich, led by neuropsychologist Katrin Preller, investigated how LSD affects our sense of self and the impact this has on social interaction. They looked at the neurobiological mechanisms involved in this process, including the role of a receptor in the brain known as serotonin 2A.

Volunteers were either given a dose of LSD, ketanserin—a drug that blocks the effects of LSD by acting on the serotonin 2A receptor—or a placebo. They were then placed in an MRI brain scanner and asked to take part in simulated social interactions during which they communicated with a virtual, human-like avatar on a screen.

They were instructed to make eye contact with the avatar, either leading or following its gaze towards an object on the screen.

The researchers found that LSD disrupted the participants' ability to coordinate their attention with the virtual avatar, indicating that the drug blurs the boundaries between oneself and others during social interactions. This phenomenon occurs due to reduced activity in two areas of the brain known as the posterior cingulate cortex and the temporal cortex.

Because the effects experienced by those who were given the LSD were blocked by the ketanserin, the researchers concluded that the serotonin 2A receptor plays a crucial role in social interaction and self-experience.

This receptor could be an ideal target for new treatments; stimulating the receptor could help those with conditions such as depression which are characterized by increased self-focus. On the other hand, blocking this receptor may be beneficial to those suffering from disorders marked by an incoherent sense of one's self, such as schizophrenia.