Embellishing the truth to impress friends on sites like Facebook may implant false memories, psychologists have warned.
A fifth of young people admit their online profile bears little resemblance to reality, and that their recollection of past events has been distorted by their own fabrications.
Young adults, aged between 18 and 24, say they frequently lie about their relationships, promotions at work and holidays. Previous research has suggested that social networks are damaging to autobiographical memory.
Psychologist Dr Richard Sherry, a founding member of the Society for Neuropsychoanalysis, said, warned that it could also lead to feelings of shame and worthlessness. "Being competitive and wanting to put our best face forward - seeking support or empathy from our peers- is entirely understandable," said Dr Sherry.
"However, the dark side of this social conformity is when we deeply lose ourselves or negate what authentically and compassionately feels to be 'us'; to the degree that we no longer recognise the experience, our voice, the memory or even the view of ourselves. When this starts to happen, feelings of guilt and distaste towards ourselves can create a cognitive trap of alienation and possibly even a sense of disconnection and paranoia."
Dr Sherry said that social media had the power to 'undermine the coherence between our real, lived lives and memories.'
The study was commissioned by the world's first anonymous online journal repository Pencourage which aims to preserve true life chronicles by allowing users to anonymously post 200 words every day to their personal journal.
Dr Sherry added: "Studies show that memories are actually modified and less accurate whenever we 'retrieve' them from our minds, to the point of entirely changing their nature over time."
"So recording our experiences through whatever medium, to later reminisce or revisit lessons we learned, is not only acceptable but desirable. In fact, looking back at our own past - however embarrassing or uncomfortable - is not just healthy but can be enjoyable."