Psychology is the study of behavior and mind, embracing all aspects of conscious and unconscious behavior as well as thought. A short explanation for psychological therianthropy is abnormal brain wiring or unconscious adaptations of the brain to experiences and possibly emotional traumas, or a combination of both. Basically, a Therian identifies as an animal because their minds interpret their existence as such. Physically, Therianthropes are human and understand that they have human bodies.
Therians don't know what causes them to identify as non-human. Therianthropy is a subjective belief based on personal experiences and not on scientific fact. There have not been any psychological or neurological studies related to Therianthropy. Therefore, both Psychological and Spiritual Therianthropes are legitimate and accepted in the community because they have similar experiences, such as shifts. Many Therians explain their identity through both spiritual and psychological experiences.
- See also: Spiritual Therianthropy
There are multiple psychological related causes found in the community for why people self-identify as Psychological Therianthropes.
Possible Causes of Psychological Therianthropy
(This list may not be exhaustive.)
- Atypical Neurology
- Imprinting/ Developmental
- Identity Formation
- Survival/ Resilience/ Unconscious Defense Mechanism
- Duality of Human and Animal Nature
- Other Causes
- Combination of Multiple Causes
This causes of psychological therianthropy include atypical neuropsychology and atypical physiology. Neurology is the scientific study of the nervous system, especially in respect to its structure, functions, and abnormalities.  Neuropsychology is a science that combines psychological observations on behavior and the mind with neurological observations on the brain and nervous system. The specialty is dedicated to enhancing the understanding of brain-behavior relationships. 
Atypical neurophysiology is the function of a brain that works significantly different from a large majority of brains. There could possibly be differences in the structure of the brain and/or nervous system that cause different behavior to develop. These differences in neurology and physiology can cause us to process sensations, perception, memory, and communication in atypical ways that we might be interpreting as non-human.
On the Therian Timeline, Wolf VanZandt hypothesized that Weres (Therians) process language differently. We don't seem to think in words, but instead, we think in images.  In the essay "A Comprehensive Introduction to a Psychological View of Therianthropy" Liesk wrote, "Quite plainly, it seems to be the case that therians work like animals do. A great number of therians report being visual thinkers, or otherwise thinking mainly in some non-verbal form." 
Imprinting and Development
Psychological Therianthropy is explained by some Therians as imprinting on non-human animals. It is possible that a child who watches animal behavior and spends more time than usual with animals instead of properly being socialized and taught behavior by a human family could learn to act like that animal.
Children who associate with animals can take that association and turn it into familiarity and identity. This behavior could become ingrained and be an integral part of one's identity throughout life. Also, without a positive human role-model, it is possible that some children my look up to and see animals as role-models instead of humans. Playing pretend as animals can internalize those feelings and also reinforce animals behaviors.
Identity is multidimensional. Identity formation begins in early childhood when infants become self-aware. Adolescents usually break away from early beliefs about themselves and their worldview to experiment and explore alternatives. Identity achievement occurs when the adolescent has explore and committed to important aspects about their identity.
Early learning creates lifelong brain organization, and children who come to identify as Therian later in life, could be developing differently from children who identity as human. This could be due to social life, the envrionment, etc that the child is exposed to. Since a lot of Therians reported pretending to be animals as children, perhaps this is an early belief about themselves that still fits their worldview and was maintained throughout adolescence and into adulthood. Of course, there could be many other explanations and personal experiences found throughout the community.
Survival/ Resilience/ Unconscious Defense Mechanism
In times of stress, whether acute or long term, survival instincts are triggered. After the threat has gone away, most humans' behavior and brain function return to normal. For some Therians, they often express that the survival instincts never diminished. The acceptance of an instinctual, animalistic self became a permanent and integral part of who they are.
According to the American Psychological Associate, psychological resilience is, "the process of adapting well in the face of adversity, trauma, tragedy, threats, or significant sources of stress."  In the APA's online brochure titled, "The Road to Resilience" one of the ten ways to build resilience includes looking for opportunities for self-discovery. "People often learn something about themselves and may find that they have grown in some respect as a result of their struggle with loss. Many people who have experienced tragedies and hardship have reported better relationships, greater sense of strength even while feeling vulnerable, increased sense of self-worth, a more developed spirituality and heightened appreciation for life."
Of course, resilience is much more complicated, but perhaps Therianthropy is a natural result of learned behaviors that have allowed many of us to deal with the hardships in our lives. The behaviors that are associated with being non-human have become a permanent part of the identity.
This could also be related to defense mechanisms. Compartmentalization is considered to be a lesser known form of disassociation, in which parts of oneself are separated from awareness of other parts and behave as if one is different from the other.  This could explain why younger Therians usually talk as if their theriotype is separate from them.
Also, it should be noted that some psychologists consider defense mechanisms and coping mechanisms to be different. The difference is that a defense mechanism is considered to be subconscious. Whereas, a person can consciously choose between different coping strategies and find which strategy works best. 
See Copinglink if you have consciously chosen a nonhuman identity.
While using long term defense mechanisms can lead to psychological problems, it seems that in most cases, Psychological Therianthropes find a balance between their human and non-human selves and they become integrated and functional.
This is similar to what Meirya called "Primal Association" in the article "Otherkin and Therian Theories of Cause or Origin".  While many people do not want to admit that humans have natural, animal instincts and impulses, we do. Therianthropy could be an acceptance of this more primitive side of our personalities, and allowing it to have a greater influence on our lives and behaviors.
However, some Therians believe that duality should not be considered a cause. The duality of human nature may be obvious to many Therians due to their personal perspective on the world, but the simple realization is not the same as a Therian awakening. Duality may be more a quality of Therianthropy than a cause of it.
The following possible causes of Therianthropy have been mentioned much less often in the community or may be considered more controversial.
Some Therianthropes believe that it can be passed down from generation to generation. That does not mean that non-human DNA has been mixed with human DNA. What is means is that some believe that there could be genetics which cause our brains to develop differently, in such a way that we interpret our lives as not completely human. Just as there have not been any psychological or neurological studies related to Therianthropy, there have also not been any genetic studies that link Therianthropy to lineage.There is currently no evidence to support this belief.
Everyone is Therian
Similar to duality, there is also the concept that everyone is Therian or has an animal-side, but few people become aware of the fact or accepting of it. Maybe everyone has the potential to awaken, but one must already be predisposed to it, then be presented with the right sort of circumstances in their life for Therianthropy to arise.
Autism Spectrum Disorder
This may be a more specific variation on the cause of Atypical Neurology. A few members of the community consider Therianthropy to be similar to or related to autism spectrum disorder. "Autism is a complex developmental brain disorder caused by a combination of genetic and environmental influences. ASD is characterized, in varying degrees, by communication difficulties, social and behavioural challenges, and repetitive behaviours and is considered to be a lifespan disorder." 
Combination of Multiple Causes
Identity is complex. Most likely there is a combination of factors that lead one to identify as Therian rather than a single cause. Many possible causes of psychological therianthropy are similar and may overlap. For example, imprinting on an animals could have influences on identity development.
This movement frames autism, bipolarity, and other neurotypes as a natural human variation rather than a pathology or disorder, and its advocates reject the idea that neurological differences need to be (or can be) cured, as they believe them to be authentic forms of human diversity, self-expression, and being.  Just as autism is seen as a variation on functioning rather than a mental disorder to be cured, Therianthropy could be seen as just a variation in the way our brains function.
- ↑ Results for psychological in alt.horror.werewolves https://groups.google.com/forum/#!searchin/alt.horror.werewolves/psychological%7Csort:date
- ↑ Merriam Webster Dictionary http://www.merriam-webster.com/dictionary/neurology
- ↑ American Psychological Associate http://www.apa.org/ed/graduate/specialize/neuro.aspx
- ↑ "Mind of the Were" Therian Timeline http://theriantimeline.com/therianthropy/the_mind_of_the_were
- ↑ Liesk, 2007. "A Comprehensive Introduction to a Psychological View of Therianthropy" http://project-shift.net/a-comprehensive-introduction-to-a-psychological-view-of-therianthropy/
- ↑ American Psychological Associate, "The Road to Resilience" http://www.apa.org/helpcenter/road-resilience.aspx
- ↑ http://changingminds.org/explanations/behaviors/coping/compartmentalization.htm
- ↑ Dr. Sharon Galor, "Defence Mechanisms vs. Coping" February 26, 2012. https://drsharongalor.wordpress.com/2012/02/26/defense-mechanisms-vs-coping/
- ↑ Meirya, 2006. "Otherkin and Therian Theories of Cause or Origin" http://project-shift.net/otherkin-therian-theories-of-cause-or-origin/
- ↑ Autism Speaks Canada http://www.autismspeaks.ca/about-autism/what-is-autism/
- ↑ https://en.wikipedia.org/wiki/Neurodiversity