Unraveling the Mysteries of Organic Mental Disorders

Most of us take a well functioning mental processes for granted. We take “the thousand natural shocks that flesh is heir to,” process the madness, and resiliently survive. However, mental faculties are delicately balanced, and under harsh conditions, may falter. Historically, people have viewed mental disorders as a matter of choice—a consequence of behaviors. Certainly, we have progressed. We now accept that many of these disorders are caused by structural lesions in the brain. These disorders are considered organic mental illnesses.

Organic mental disorders can manifest in various ways depending on the underlying cause and affected area of the brain. Some common examples include delirium, dementia, amnesia, and other cognitive disorders. These disorders can be temporary or permanent, and their severity can range from mild to severe.

It is important to differentiate organic mental disorders from primary psychiatric disorders, which are not caused by any known physical or organic factors. Proper diagnosis and treatment of organic mental disorders often require a comprehensive medical evaluation, including imaging tests, blood work, and other diagnostic procedures.

Three Classes of Mental Disorders

Declining mental functions may occur for a variety of reasons. When there is a physical cause for a mental disorder, either from disease or injury, we list these disorders as organic. The term organic mental disorders is used to describe all diagnostic groups in which an organic brain disease or a known physical injury is the main cause for the mental symptoms.

Organic Mental Disorders

We can subdivide organic mental disorders into two subcategories:

1. Mental disorders due to brain diseases (Alzheimer’s disease, Huntington’s disease, brain cancer, etc…), brain injuries (car accidents, traumatic brain injury, etc…) or developmental brain disorders (ADHD, learning disorders, autism, etc…).
2. Mental disorders due to psychoactive substance use

Psychotic Disorders

We designate the second category of mental disorders with psychosis. These disorders fall under three subcategories:

• Paranoid or delusional disorder
• Manic-depressive disorder
• Schizophrenia 

Non-organic, Non-Psychotic Disorders

The third category is composed of all mental disorders that do not have organic or psychosis as the basis of the disorder (Xu, 2009). Historically, these disorders have been referred to as neurosis. Included in third category are the neurotic diseases formerly known as axis II disorders, mostly known as the personality disorders. These disorders are seen as functional disorders because they serve a functional purpose for dealing with harsh environments. They serve a protective purpose working as a defense mechanism against threats to the ego.

Examples of Organic Mental Illnesses

A notable example of an organic mental disorder from psychological history is the case of Phineas Gage. While working on a blasting crew in 1848, due to an error, an accidental explosion thrust his tampering iron through his brain, largely removing most of his left prefrontal cortex.

​Gage survived the accident but suffered from extreme emotional lability after the accident. The traumatic brain injury impacted Gage’s ability to regulate emotions. Reportedly, towards the end of Gages life he began to regain many of the emotional regulation skills he initially lost during the accident.

My dad is another excellent example of an individual with an organic mental disorder. I mentioned him in a number of articles over the years (e.g. Stoically Aloof, An Example of Kindness). My dad suffers from Alzheimer’s disease. Once a retired engineer, he now is completely dependent on others for his care. Alzheimer’s disease severely diminishes his mental capacity.

All Disorders Have an Organic Basis

While we only consider only certain mental disorders as organic mental illnesses, all mental states and conditions are organic in basis. All mental disorders “are rooted in neural activity” (Kihlstrom, 2005).

While categories and subcategories serve a purpose, they have limitations.

William James wrote:

“Most cases are mixed cases, and we should not treat our classifications with too much respect” (James, 1902).

Basically, we must accept the unknown inherent in complexity. Certainly, we can point to some of the causes; but there is always more to the story.

Most mental disorders have both a biological and environmental component. The biological givens create certain vulnerabilities that may activate a disorder when exposed to overwhelming stress. The diathesis stress model theorizes that, “biological or genetic traits (diathesis) interact with environmental influences (stressors) to produce disorders such as depression, anxiety, or schizophrenia” (Murphy, 2021).

Treatment of Organic Mental Disorders

The treatment of organic mental disorders typically involves a multifaceted approach aimed at addressing the underlying physical causes. Medical professionals may start with comprehensive evaluations, including neuroimaging and laboratory tests, to identify any structural or biochemical abnormalities in the brain. Depending on the diagnosis, treatments may include pharmacological interventions such as medications that target neurotransmitter imbalances associated with specific disorders.

For instance, individuals diagnosed with Alzheimer’s disease might benefit from cholinesterase inhibitors that can help manage cognitive symptoms. Additionally, therapies focusing on lifestyle modifications—such as nutrition, exercise, and sleep hygiene—can also play a crucial role in supporting overall brain health.

In conjunction with medical treatment, rehabilitation services are essential for improving an individual’s functioning and quality of life. This often includes cognitive rehabilitation therapy aimed at enhancing memory and problem-solving skills through structured exercises tailored to the individual’s needs.

Support from mental health professionals is vital for guiding patients through their recovery journey while providing education to family members about how to best support their loved ones. Furthermore, group therapy sessions can foster social connections among individuals facing similar challenges—enhancing emotional well-being by reducing feelings of isolation and encouraging shared coping strategies. By combining these approaches, treatment plans for organic mental disorders can be holistic and person-centered, ultimately aiming to restore autonomy and improve daily living conditions for those affected.

Associated Concepts

• Biopsychosocial Model: This model integrates biological, psychological, and social factors to understand mental health and illness. It suggests that organic mental illnesses can result from a complex interplay between genetic predispositions, psychological stressors, and social environments.
• Psychoneuroimmunology: This interdisciplinary field studies the interaction between psychological processes, the nervous system, and the immune system, all of which are relevant to understanding allostatic load.
• Cumulative Risk Theory: This theory proposes that individuals may face an increased risk of negative outcomes when they are simultaneously exposed to multiple risk factors, rather than just one.
• Medical Model: In psychology, the medical model views mental disorders, including organic mental illnesses, as having an organic or physical cause, focusing on genetics, neurotransmitters, neurophysiology, and neuroanatomy.
• Cognitive Theory: This theory looks at the mental processes like memory and decision-making. In the context of organic mental illnesses, cognitive theory helps in understanding how brain dysfunction affects these processes.
• Stress and Coping Theory: Developed by Lazarus and Folkman, this theory explains how stress affects an individual and how coping mechanisms can mitigate stress-related disorders.
• Diathesis Stress Model: This theory that suggests that people have an underlying predisposition (diathesis) towards certain psychological conditions, and that the manifestation of these conditions is determined by the presence of stressors.
• Neuroscience: The study of the nervous system, particularly the brain, is fundamental to understanding organic mental illnesses. Neuroscience explores how alterations in brain structure and function can lead to various psychological symptoms.

A Few Words by Psychology Fanatic

While we may be more apt to express empathy with those suffering from an organic mental illness, we should compassionately and patiently reach out to all those suffering from disorders. In conclusion, organic mental illnesses are just a label. We, no matter what the cause, should treat those suffering with respect. Whether a disorder is a coping mechanism gone haywire, or a organically inherited disease doesn’t matter. A human being is struggling, experiencing pain, and needs acceptance.

Last Update: January 29, 2026

References:

James, William (1902/1982). The Varieties of Religious Experience. ‎Independently published. ISBN: 9780684842974
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Kihlstrom, J. (2005). Dissociative Disorders. Annual Review of Clinical Psychology, 1, 227-253. DOI: 10.1146/annurev.clinpsy.1.102803.143925
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Murphy, T. Franklin (2021) Diathesis Stress Model. Psychology Fanatic. Published: 9-7-2022; Accessed: 12-19-2022. Website: https://psychologyfanatic.com/diathesis-stress-model/
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Xu, Y. (2009). The Third Category of Mental Disorders. Culture, Medicine and Psychiatry, 33(4), 496-500. DOI: 10.1007/s11013-009-9153-3
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