Why would anyone post dozens of fake messages of abuse about themselves on a social media website? And then complain that they are the victims of bullying? Could it be a form of research? Self-hatred? Or a perverse effort to find love? If this self-abuse is the "answer", then what on earth's the question?

We can't ask 14-year-old Hannah Smith because it may have been precisely this exercise that killed her. During a pre-inquest review into her death last week, it emerged that there was no evidence she was the victim of trolling, with her father revealing that police believe she sent the anonymous messages to herself. If true, Hannah killed herself last August in the ultimate act of self-criticism.

And then there was 24-year-old Michelle Chapman repeatedly posting self-slanders – of a "very unpleasant sexual nature" – from false Facebook accounts in the name of her father and step-mother before having them both arrested. After a legal investigation, Michelle found herself in jail for 20 months.

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What is the profit in pretending that people hate you when they don't? In the Chapman case, it was possibly some sort of response to a family fracture but these don't usually involve assassinating your own character as a means of redress. Statistics are scant help. One research study from the Massachusetts Aggression Reduction Centre found that 9 per cent of 617 students might be tempted to bully themselves online falsely. When asked about potential motives, they came up with "cries for help", "gaining adult attention" or "forcing peers to support them".

In the pantheon of attention-seeking disorders, self-trolling has much in common with self-harming and self-starving. There are possible parallels with Münchausen's syndrome where patients typically fake illness to gain care. Even Hilaire Belloc's poem "Matilda" (who "told such dreadful lies it made one gasp") may be relevant because the child crying wolf – rather than asking for what is wanted – seems to be an underlying mechanism.

So in the absence of data or definitions, what to make of it? As a therapist, I think we're confronted by people in severe distress feeling insecurely attached to parents, guardians and peers. As a result, mental processing remains juvenile whatever their biological stage. Their sense of personal identity seems fluid, fragile or miscalculated (one reason to denounce yourself in public is to conduct a rather risky opinion poll). Fantasy becomes reality – it's notable that some of the American students in the study came to believe that they'd been trolled for real just because their own words in print said that they had.

It's no help that the inner world of emotionally damaged children already contains its own bully. Starve children of enough affection and stability and they're too terrified to decide that the world is mad; instead, they invent a fantasy of themselves as evil. I think it's quite a simple step to graduate from such a mindset to active self-trolling. Better to self-blame aloud in four-letter tirades than conclude that nobody cares. Bad attention is always better than none.

And yet despite feeling hopeless, the child is also angry enough to act. Self-trolling differs from self-harming by being more exhibitionistic than secret. All of us when disappointed in love tend to seek power as an alternative. The self-troller is masochistically gratified up to the moment their self-abuse causes social disaster.

Is this type of behaviour new? No. Every town in history has probably contained someone who sent a poison-pen letter to themselves and basked in the resultant outrage. But it is probably no help that ours is an era of digital delusion. First, with a computer you can transmit much bigger messages. Second, we already suffer from the misconception that happiness is a Twitter following. Think @MsSallyBercow (5,508 followers) over her various tweeting mishaps. The result is that we are slow to perceive that the internet is both illusory and lethal.

This subject of cyber self-harm matters because children die. We need to remember that when young people say one thing it may often mean the opposite.

Phillip Hodson is from the United Kingdom Council for Psychotherapy (psychotherapy.org.uk). His views are personal.