..Some researchers, beginning with Sigmund Freud, consider the fear of the dark as a manifestation of separation anxiety disorder
Separation anxiety disorder is a psychological condition in which an individual experiences excessive anxietyregarding separation from home or from people to whom the individual has a strong emotional attachment(like a father, mother, grandparents, and brothers or sisters). Separation Anxiety Disorder (SAD), is characterized by significant and recurrent amounts of worry upon (or anticipation of) separation from a child or adolescent's home or from those to whom the child or adolescent is attached.
Those suffering from SAD may worry about losing their parents and/or getting lost or kidnapped. They often refuse to go to certain places (e.g., school) because of fears of separation, or become extremely fearful when they are left alone without their parents. These children and adolescents may also refuse to sleep alone, experience nightmares about separation, or experience various physical complaints (e.g., body-aches, nausea) when separated from their parents. Separation anxiety may cause significant impairment in important areas of functioning, (e.g., academic and social). The duration of this problem must last for at least four weeks and must present itself before the child is 18 years of age.
The fear of the dark is a common fear among children and to a varying degree is observed for adults. Fear of the dark is usually not fear of the darkness itself, but fear of possible or imagined dangers concealed by the darkness. Some degree of fear of the dark is natural, especially as a phase of child development. Most observers report that fear of the dark seldom appears before the age of 2 years.[ When fear of the dark reaches a degree that is severe enough to be considered pathological, it is sometimes called nyctophobia (from Greek νυξ, "night" and φοβια, phobia), scotophobia, from σκότος - "darkness", or lygophobia, from λυγή - "twilight" and achluophobia.
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