Identity alteration can be defined as the experience of one's sense of self becoming temporarily changed to feel as if it is comprised of different concepts than that which it previously did. For example, while a person may usually feel that they are exclusively their “ego” or a combination of their “ego” and physical body, during this state their sense of identity can change to include the external environment or an object they are interacting with. Alternatively, a person could feel as if their sense of self embodies nothing at all, which is an experience commonly referred to as depersonalisation.
The concept of identity itself can be defined as a fundamental and near universal component of human perception that provides the experience of feeling like a self, a separate system intrinsically differentiated from the external world. This feeling is commonly referred to as one's sense of identity, ego, or selfhood. In general conversation, it is referred to using pronouns such as "I", "me", "mine", and "myself" as a tool for contrasting one's self from other people and any other system which is not felt to be them.
However, it is worth noting that rather than being a static, unmoving, or objective concept that it is often assumed to be, a person's identity can actually be experienced in many ways. There is no component of the human brain, body, or consciousness which can be singled out as the location of a person's individual selfhood. The self is thus speculated to be a learned and constructed concept that arises through a combination of experience, the structure of language, and social interactions with other people. This notion is in stark contrast to the common Western cultural conception that human beings each contain a tangible identity that is a real and separate system from that which resides around it.
Within traditional religions, the intrinsic nature of human identity differs depending on the specific doctrine. For example, Abrahamic religions such as Christianity and Islam use an inherently dualist approach which claims that the self is a soul which resides within the body and is intrinsically separate from its external environment. In contrast, Eastern religions such as Hinduism and Buddhism take an approach known as monism, or nondualism which generally speaking, assumes that the separate self is illusory and that there is no difference between one's identity or soul and the "external" universe which it resides in.
In regard to identity alteration, there are a total of 5 distinct levels of identity which a person can experience. These various altered states of identity have been arranged into a levelling system that orders its different states from least to the most number of concepts one's identity is currently attributed to. These levels are described and documented below:
1. Total absence of attributed identity (depersonalization)
The lowest level of identity can be described as the sensation that there is a complete absence of having any sense of self at all. This is referred to in psychiatry as "depersonalization". It can be described as an anomaly of self-awareness that consists of a feeling of watching oneself act as one normally would, while also feeling is if they have no control over the situation. It can occur under the influence of hallucinogenic substances, particularly dissociatives, and may persist for some time after sobriety. During this state, the affected person may feel that they are "on autopilot" and that the world has become vague, dreamlike, less real, or lacking in significance. Individuals who experience depersonalization often feel divorced from their own personal physicality by no longer sensing their body sensations, feelings, emotions, and behaviors as belonging to a person or identity. It is also often claimed by people who have depersonalization that reality seems unreal, distant or hazy. Depersonalization can sometimes be distressing to the user, who may become disoriented by the loss of a sense that their self is the origin of their thoughts and actions. However, it does not have to be an inherently negative altered state of awareness, as it does not directly affect a person's emotions or thought patterns.
It is perfectly normal for many people to slip into this state temporarily, often without even realizing it. For example, many people often note that they enter a detached state of autopilot during stressful situations or when performing monotonous routine tasks such as driving.
In psychology, chronic depersonalization that persists during sobriety for prolonged periods of time is identified as "depersonalization disorder" and is classified by the DSM-IV as a dissociative disorder. While degrees of depersonalization are common and can happen temporarily to anyone who is subject to an anxiety or stress provoking situation, chronic depersonalization is more common within individuals who have experienced a severe trauma or prolonged stress and anxiety. The symptoms of both chronic derealization and depersonalization are common within the general population, with a lifetime prevalence of up to 26-74% and 31–66% at the time of a traumatic event. It has also been demonstrated that derealization may be caused by a dysfunction within the brains visual processing center (occipital lobe) or the temporal lobe, which is used for processing the meaning of sensory input, language comprehension, and emotion association.
Within the context of identity altering effects, depersonalization can be considered as being at the opposite end of the identity spectrum relative to states of unity and interconnectedness. This is because during depersonalisation, a person senses and attributes their identity to nothing, giving a sense of having no self. However, during a state of unity and interconnectedness, one senses and attributes their identity to everything, giving a sense that the entirety of existence is their self.
Depersonalization is often accompanied by other coinciding effects such as anxiety and a very similar psychological disorder known as derealization. It is most commonly induced under the influence of moderate dosages of dissociative compounds, such as ketamine, PCP, and DXM. However, it can also occur to a lesser extent during the withdrawal symptoms of stimulants and depressants.
2. Self-contained separate identity
The second level of identity can be described as feeling as if one's identity is attributed to their brain and/or body. This is often said to feel as if one is a consciousness, the guiding force located within a body which is immersed in and interacting with a distinctly separate external environment. It is usually accompanied with a sense of free will or agency over all the thoughts and actions the person makes, which results in them feeling as if their decision-making processes are arising from an internal source which is not necessarily determined by cause and effect in the same manner as external systems.
A self-contained separate identity is by far the most common form of identity. Mainstream Western cultural notions consider this conception of the self to be the self-evident or logical way to perceive the world and the only form of identity which isn't intrinsically delusional. Despite being culturally normative, this belief has received considerable debate and criticism within modern neuroscience and philosophy. 
Although drastically altered in comparison to that of sobriety, it is worth noting that hallucinatory states such as ego replacement and 2nd person perspective hallucinations typically still fall under the classification of this level. In both cases, a person still feels as if they are a separate agent facing the external world, but have the perception of being a different identity than their sober self.
3. Identifying with specific "external" systems
The third level of identity alteration can be described as feeling as if one's identity is attributed to (in addition to the body and/or brain) specific external systems or concepts within the immediate environment, particularly those that would usually be considered as intrinsically separate from one's own being.
The experience itself is often described as a loss of perceived boundaries between a person’s identity and the specific physical systems or concepts within the perceivable external environment which are currently the subjects of their thoughts or focus. This creates a sensation of becoming inextricably "connected to", "one with", "the same as", or "unified" with whatever the perceived external system happens to be.
There are an endless number of ways in which this level manifests itself, but common examples of the experience often include:
- Becoming unified with and identifying with a specific object one is interacting with.
- Becoming unified with and identifying with another person or multiple people, particularly common if engaging in sexual or romantic activities.
- Becoming unified with and identifying with the entirety of one's own physical body.
- Becoming unified with and identifying with large crowds of people, particularly common at raves and music festivals.
- Becoming unified with and identifying with the immediately perceivable external environment, but not the people within it.
4. Identifying with all perceivable "external" systems
The fourth level of identity alteration can be defined as feeling as if one's identity is attributed to the entirety of their immediately perceivable external environment.
The experience itself is often described as a loss of perceived boundaries between a person’s identity and the entirety of their sensory input or the currently perceivable external environment. It creates a sensation in the person that they have “become one with their surroundings.” This is felt to be the result of a person’s sense of self becoming attributed to not just primarily the internal narrative of the ego, but in equal measure to the body itself and everything around it which it is physically perceiving through the senses. This sensation creates the compelling perspective that the person is the external environment experiencing itself through a specific point within it, namely the physical sensory perceptions of the body their consciousness currently resides in.
It is at this point that a key component of the high-level identity alteration experience becomes an extremely noticeable factor. Once a person's sense of self has become attributed to the entirety of their surroundings, this new perspective completely changes how it feels to physically interact with what was previously felt to be an external environment. For example, when a person is not in this state and is interacting with a physical object, it typically feels as though they are a central agent acting on the separate world around them.
However, while undergoing a state of unity with the currently perceivable environment, interacting with an external object consistently feels as if the whole unified system is autonomously acting on itself with no central, separate agent operating the process of interaction. Instead, the process suddenly feels as if it has become completely decentralized and wholistic, as the environment begins to autonomously and harmoniously respond to itself in a predetermined manner to perform the interaction carried out by the individual.
5. Identifying with all known "external" systems
The fifth level of identity alteration can be defined as feeling as if one's identity is simultaneously attributed to the entirety of the immediately perceivable external environment and all known concepts that exist outside of it. These known concepts typically include all of humanity, nature, and the universe as it presently stands in its complete entirety. This feeling is commonly interpreted by people as becoming one with the universe.
When experienced, the effect creates the sudden perspective that the person is not a separate agent approaching an external reality, but is instead the entire universe as a whole experiencing itself, exploring itself, and performing actions upon itself through the specific point in space and time which this particular body and conscious perception happens to currently reside within. People who undergo this experience consistently interpret it as the removal of a deeply embedded illusion, with the revelation often described as some sort of supposedly profound “awakening” or “enlightenment.”
Although they are not necessarily literal truths about reality, at this point, many commonly reported conclusions of a religious and metaphysical nature often begin to manifest themselves as profound realizations. These are described below:
- The sudden and total acceptance of death as a fundamental complement of life. Death is no longer felt to be the destruction of a person, but simply the end of this specific point of a greater whole, which has always existed and will continue to exist and live on through everything else in which it resides. Therefore, the death of a small part of the whole is seen as an inevitable, and not worthy of grief or any emotional attachment, but simply a fact of reality.
- The subjective perspective that the person's preconceived notions of "god" or deities can be felt as identical to the nature of existence and the totality of its contents, including oneself. This typically entails the intuition that if the universe contains all possible power (omnipotence), all possible knowledge (omniscience), is self-creating, and self-sustaining then on either a semantic or literal level the universe and its contents could also be viewed as god.
- The subjective perspective that the person, by nature of being the universe, is personally responsible for the design, planning, and implementation of every single specific detail and plot element of one's personal life, the history of humanity, and the entirety of the universe. This naturally includes personal responsibility for all humanity's sufferings and flaws but also includes its acts of love and achievements.
Similar accounts of the experience of unity with the universe and the apparent illusory nature of the self can be found across a surprisingly large variety of independent religious, philosophical, and psychological sources. A number of these have been collected and listed as a set of documented examples below:
- Egolessness is a documented emotional state within psychology where one feels no ego (or self) and no distinct sense of self apart from the world around oneself. This is often described as feelings of oneness and being inextricably woven into the fabric of one’s surroundings or environment.
- Monism is a philosophical position which argues that there is only one thing which all things are not separate from and it works together as a unified system of behavior.
- Dialectical monism is a philosophical position which argues that the appearance of duality arises from the mind's need to impose divisions and boundaries upon an essentially unified whole. Thus, for the dialectical monist, reality is ultimately a single unified system but can usually only be experienced in terms of division.
- Oceanic feeling is a state within psychology which is described as a sensation of an indissoluble bond of being connected with the external world in its integral form.
- Nondualism is a philosophy found within many religions which states that there is no difference between the concept of the external environment and the self.
- Alan Watts is a philosopher who spoke extensively about the illusory nature of the self. His lectures can be found for free on the Pirate Bay and in parts within many videos across YouTube. His book “The Book on the Taboo of Knowing Who You Are” is dedicated to a formal explanation of the philosophies and logic behind this perspective and can be found within the form of a free PDF.
- Interconnectedness is a philosophical concept which defines itself as part of the terminology of a world view which sees a oneness in all things. This is based on the idea that all things are of a single underlying substance or reality and that there is no true separation deeper than appearances.
- Samadhi is a Buddhist concept described as a state of mind in which the consciousness of the experiencing subject becomes one with the experienced object.
- The Ego-Tunnel: The science of the mind and the myth of the self is a scientific book which discusses the concept of an illusory self from the perspective of modern neuroscience and psychology.
- Overview effect is a cognitive shift in awareness reported by some astronauts and cosmonauts during spaceflight, often while viewing the Earth from orbit or from the lunar surface.
- How LSD Makes Your Brain One With The Universe (NPR.org)
- Sam Harris: The self is an illusion (YouTube)
- Being The Universe (tumblr)
Compounds within our psychoactive substance index which may cause this effect include:
- Amanita muscaria
Annectdotal reports which describe this effect with our experience index include:
- Experience: 15mg 2C-B (oral) - A pleasant low-dose evening with Nexus
- Experience: 22mg 2C-B (oral) / 100ug 1P-LSD (sublingual) - My first time tripping alone (2 days in a row)
- Experience: 36mg 4-AcO-DiPT - Truly, one for the psychedelic animals among us
- Experience: 5-EAPB (60mg) + 2-FMA (20mg) + 4-AcO-DMT (10mg) - Emotional catharsis
- Experience:1000 Morning Glory seeds - Rediscovering the Self
- Experience:100ug 1P-LSD - A Fear and loathing into Bliss
- Experience:1050 µg 1cP-LSD - The matrix
- Experience:120mg - Garden of The Gods
- Experience:150mg MDMA + 20mg 2C-B - I designed it this way myself
- Experience:1mg 25c-NBOMe - Experiment in my room
- Experience:2 tabs DOB - My DOB Nightmare
- Experience:2.5g Syrian rue + 6g Mimosa Hostilis - Becoming God (my second experience with unity)
- Experience:225mg Pregabalin +Cannabis -Bliss and Serenity; a hedonistic evening
- Experience:225ug LSD + 9g cubensis - Galactic Melt and the Meverse
- Experience:250mg DXM - DXM Itch and Trip Report
- Experience:25mg 2C-B - Hard raving at home
- Experience:25mg 3-MeO-PCP - Enhanced film experience
- Experience:25mg Deschloroketamine - My first time orally dosing DCK
- Experience:2C-P (approx. 35mg) - Asymmetrical Terror and the Geometric Sea
- Experience:3 Grams of Mushrooms - Reset on my Life, Experiencing Satori and the Cosmic Perspective
- Experience:3-MeO-PCP - Extreme psychosis
- Experience:3.5g psilocybe cubensis - Relinquishing of Material Chains/Fear and Desolation
- Experience:300mg DXM + 25mg DMT + Cannabis - A crazy night
- Experience:300µg AL-LAD - Don't worry, because you're everyone!
- Experience:300µg LSD - Togetherness and the Silent Dusk
- Experience:337mg DMT fumarate - A Day With DMT
- Experience:3g mimosa / 3g syrian rue - Connecting with my body
- Experience:4-AcO-DMT + 200mg Pill
- Experience:4-HO-MiPT / A care free psychedelic getaway
- Experience:4.5g - The Grand Introduction to Beauty and Fear
- Experience:40mg - Brothermind and the Forest's Hand
- Experience:4x 200ug tabs - You do not need to understand
- Experience:5.3g psilocybe cubensis - Dimensional Circumstance and the Fabric of Understanding
- Experience:60mg 4-AcO-DMT Nonstop Quasi-Orgasmic Objectless Euphoria
- Experience:75mg 3-FMA - Perfect Blend of Euphoria and Functionality
- Experience:800 seeds LSA - My First Trip Ever
- Experience:A combination of DOC, 5-MAPB, 5-MeO-DMT, ETH-LAD, Cannabis, Pentedrone
- Experience:BK-2C-B - Various experiences
- Experience:Mushrooms and Snuff Films -- Trip Report (3.5 grams)
- Experience:Unknown Dose DOC (Insufflated) - Overdosing and Terifying Ego Death
- Experience:Unknown dosage / 1 tab DOC - Psychedelia Turned Into Stimulant Psychosis
- Experience:~150mg MDA(oral) - a case of mistaken identity
- The Oxford Handbook of the Abrahamic Religions (Dualism) | https://books.google.com/books?id=IR6DCgAAQBAJ&pg=PA416&lpg=PA416&dq=abrahamic+religions+dualism&source=bl&ots=QbSwQ9NwFL&sig=DbBYFrrpk9MYJG7RDNNmu3h3dtY&hl=en&sa=X&ved=0ahUKEwik9K3HkvnOAhWJyyYKHZOnBWMQ6AEILTAC#v=onepage&q=abrahamic%20religions%20dualism&f=false
- Hindu and Buddhist Nonduality: Conflict in the New Church Mind? | http://www.soc.hawaii.edu/leonj/isi-news-nonduality.html
- Walsh, S. L., Strain, E. C., Abreu, M. E., & Bigelow, G. E. (2001). Enadoline, a selective kappa opioid agonist: comparison with butorphanol and hydromorphone in humans. Psychopharmacology, 157(2), 151-162. https://doi.org/10.1007/s002130100788
- American Psychiatric Association (2004). Diagnostic and Statistical Manual of Mental Disorders DSM-IV-TR (Text Revision). American Psychiatric Association. ISBN 0-89042-024-6.
- Espiard, M. L., Lecardeur, L., Abadie, P., Halbecq, I., & Dollfus, S. (2005). Hallucinogen persisting perception disorder after psilocybin consumption: a case study. European Psychiatry, 20(5), 458-460. https://doi.org/10.1016/j.eurpsy.2005.04.008
- The epidemiology of depersonalisation and derealisation. A systematic review | https://www.ncbi.nlm.nih.gov/pubmed/15022041
- Separating depersonalisation and derealisation: the relevance of the “lesion method” (bmj.com) | http://jnnp.bmj.com/content/72/4/530
- The self is an illusion: a conceptual framework for psychotherapy (sagepub.com) | http://journals.sagepub.com/doi/abs/10.1177/1039856216689531
- The self-illusion and psychotherapy (PsychologyToday) | https://www.psychologytoday.com/blog/the-skeptical-shrink/201703/the-self-illusion-and-psychotherapy
- The Self is Not an Illusion (PsychologyToday)https://www.psychologytoday.com/blog/the-self-illusion/201205/what-is-the-self-illusion
- The Ego Tunnel (pdf) | http://xenopraxis.net/readings/metzinger_egotunnel.pdf
- The Illusion of the Self An Interview with Bruce Hood | https://www.samharris.org/blog/item/the-illusion-of-the-self2
- The illusion of the self (philosophynow) | https://philosophynow.org/issues/97/The_Illusion_of_the_Self