AUSTRALIAN teenagers are becoming "text addicts" and risk a range of serious mental and physical disorders from depression to "repetitive thumb syndrome".

A study into youth communication habits identified the risks teens face from texting excessively every day.

Anxiety, insecurity, depression and low self-esteem have been identified as symptoms common among text addicts.

Jennie Carroll, a technology researcher from RMIT University in Melbourne, has studied of the effects of modern communication since 2001 and said the mobile phone had become meshed into teenagers' lives.

"Texting is quite tribal — it is just what teenagers do with phones," she said.

Ms Carroll's study identified four distinct disorders — textaphrenia, textiety, post-traumatic text disorder and binge texting.

Textaphrenia is thinking a message had arrived when it hadn't, while textiety is the anxious feeling of not receiving or sending text messages.

"With textaphrenia and textiety there's a feeling no one loves me, no one's contacted me," Ms Carroll said.

Post-traumatic stress disorder involved physical and mental injuries from texting.

"Like walking into things while texting and even crossing a road without realising," Ms Carroll said.

"Young people are in a bubble doing their communication and focused on that."

"There were reports from Japan of 'repetitive thumb syndrome' and thumbs growing because of texting leading to 'Monster Thumbs'."

Binge texting is when teens send multiple texts to feel good about themselves and try to attract responses.

"This is the reverse of the anxiety — you think you've been left out of the loop so you send a lot of texts and wait for responses," Ms Carroll said.

Figures released by Boost Mobile, a reseller of the Optus network, showed text messaging had increased by 89 per cent in the last two years, with one teenage customer sending an incredible 4000 texts messages over nine days.

Manly teenagers Ruth Williams, 18, and Annika Tyr-Egge, 19, are textaholics who each send between 50 and 120 text messages every day.

"I always have my phone on me — it never leaves my side," Ms Williams said.

"Texting is how I connect to my friends. I rarely call people anymore."

Ms Tyr-Egge admitted being a heavy texter but said that was part of being a teenager.

"Texting has become part of the Gen Y culture — it's an everyday thing that all of us do," she said.

Texting times

Textaphrenia

Hearing texts or feeling mobile vibrate when it hasn't. Constantly checking mobile to see if a message has arrived.

Textiety

Anxiety teens feel when they haven't received a text or are unable to send texts. They feel like they have no friends and also over-analysing why people don't reply.

Post-traumatic Text Disorder

Physical and mental injuries sustained while texting (like walking into poles) and feelings of depression when no one contacts them.

Binge texting

Sending lots of individial texts or group texts to engage as many responses as possible so they can still feel like part of the group.

What teens can do to reduce text addiction

Better sense of self and healthy self-esteem. Stay active and establish regular face-to-face contact with friends and family.

What parents can do to help their children

Set ground rules about the use of their mobiles while they are at home and encourage communication at family outings and family meals.