What causes loneliness?
Human beings are born with the need for contact and tenderness, from infancy to adulthood there is a yearning for interpersonal intimacy.
For example as an infant one relies heavily on their guardians for survival. They receive food, shelter, water, and love from the ones that care for them. As an infant grows into adolescence they begin to rely on their peers for social support and identification. Lastly, in adulthood, one finds fulfillment in a lifelong partnership. Someone to build a family with and support growth.
If any of these needs are obstructed or hindered, than the chances of the individual to fall ill with real loneliness is greatly increased.
Constructive loneliness is self-chosen seclusion. Usually isolation that is sought for the purpose of artistic or scientific creation. The main characteristics of constructive loneliness are that it is temporary and voluntarily sought out. Constructive loneliness is intrinsically motivated and purpose driven. Fromm-Reichmann argues that nearly all creative works of originality are conceived in states of constructive loneliness. Constructive loneliness is not synonymous with real loneliness.
By Rowena Low (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons