Social contagion, the psychiatric symptom pool and non-suicidal self-injury.

There is evidence that social contagion plays a role in shaping the clinical presentation of some psychiatric symptoms, particularly affecting features that vary over time and culture. Some symptoms can increase so rapidly in prevalence that they become 'epidemic'. The mechanism involves a spread through peers and/or the media. Within broader domains of psychopathology, this process draws from a 'symptom pool' that can determine which specific symptoms will appear. This article illustrates these mechanisms by focusing on non-suicidal self-injury (NSSI), a syndrome that has been subject to social contagion and whose prevalence may have increased among adolescents.