Thalassophobia (from Ancient Greek θάλασσα (thálassa) 'sea' and φόβος (phóbos) 'fear')[1] is the persistent and intense fear of deep bodies of water, such as the ocean, seas, or lakes.

[3] Researchers have proposed that the fear of large bodies of water is partly a human evolutionary response, and may also be related to popular culture influences which induce fright and distress.

[8][4] A 2016 study by Nicholas Carleton establishes that the ‘Fear of Unknown’ is an evolutionary mechanism that has driven the survival of the human species since the beginning.

[9] Showing fear toward deep bodies of water is in effect justified since in ancient times humans understood that their survival was reliant on remaining in terrestrial land and not aquatic environments.

[10] Martin Antony, Professor of Psychology at Toronto Metropolitan University and co-author of The Anti-Anxiety Workbook, states that: "[f]rom an evolutionary perspective, it makes sense that humans would develop a tendency to fear and avoid deep water because of all the associated risks".

Texts like William Shakespeare's The Tempest featured a shipwreck as the driving force behind its narrative and gave the sea an "otherworldly" and "evil" personification.

[citation needed] Authors of Beasts of the Deep: Sea Creatures and Popular Culture Sean Harrington and Jon Hackett believe that these narratives are a driving force for the widespread fear of oceans.

[4] Literature of the gothic and supernatural have gravitated toward the sea as a fertile environment, and as a result create an unpleasant and fearful image in the minds of audiences.

[12] Similarly, real cases of ships like the Titanic sinking with their passengers drowning have been made terrifyingly realistic through their movie versions.

In addition to this, observing others, particularly parental figures and other influential adults, who also had a fear of deep water are considered contributing factors for developing thalassophobia later in life.

[13] Such genetic factors include having a family member with thalassophobia, personal mental state such as being negative, sensitive, or anxious, and even hearing terrifying stories on water accidents.

Considering that humans are land mammals and we rely on our eyesight to collect food, it is evolutionarily coded into our lives that the deep sea opposes that environment.

[15] Many things can trigger thalassophobia, such as coming in contact with or thinking about the ocean, lakes, boats, swimming, scuba diving, submarines, sea creatures, or photographs and movies about anything stated.

It is extremely important to note that if left untreated, thalassophobia could lead to other mental disorders such as post-traumatic stress-disorder, anxiety, depression, and/or panic-attacks.

CBT is a type of psychotherapeutic treatment that helps patients learn how to identify and manipulate disturbing thought patterns into positive and realistic behaviors.

A meta-analysis study in 2013 found that CBT has a positive effect in changing the neural pathways and activation of the brain on patients with phobias, resulting in more controlled behavior when exposed to the fear.

[citation needed] Majority of individuals who have thalassophobia actively avoid the situation they are afraid of, which in return creates a false and even more frightening fake reality.

[22] The underlying theory behind systemic desensitization is classical conditioning which aims to replace feelings of fear and anxiety with a state of calm.

These variations include:[23] In vivo exposure: This is a technique whereby patients are instructed to directly face a feared object, situation, or activity in real life.