This study provides the synonyms for the terms deliberate self-harm and self-destructive behaviour, together with a psychological portrait of self-harming adolescents, the consequence of self-harm, the purpose of self-harm, and the forms of self-harm. It also presents the results of a survey regarding the prevalence of people with non-suicidal self-harming behaviour, the gender of people with non-suicidal self-harming behaviour, the age of the first non-suicidal self-harming behaviour in these people, the frequency of non-suicidal self-harming behaviour in these people, the association of the non-suicidal self-harming behaviour with substance misuse in these people, the relationships of the people with non-suicidal self-harming behaviour with their fathers, mothers, and siblings, the relationships of the people with non-suicidal self-harming behaviour with their friends, the possible causes of self-harming behaviour in these people, and the relationship of people with non-suicidal self-harming behaviour with religion. Some of the results confirmed literature results, while others shed a new light on other aspects related to people with non-suicidal self-harming behaviour.