A teenage girl locks her mother for four hours in a room. A mother tries to commit suicide, unable to put up with her only son?s tantrums. Another lone child sets fire to his own house to vent his anger, while yet another only child mercilessly beats up his parents.

The cases may be unrelated, but they have a common factor ? the only child.

Parents of only children are increasingly visiting psychologists these days, failing to cope with unreasonable demands from their children and their sudden aggressive behaviour. Common complaints include anger outbursts, irritation and hatred of parents.

A significant increase in such cases in three years ? about two to three a day from four to five a month ? has prompted neurologists, psychiatrists and psychologists to put their heads together and find out what is wrong.

The causes, say experts, range from working parents trying to make up for time spent away from their children by showering them with lavish gifts, or putting too much pressure on them from early childhood.

?In some cases, we have found over-protection and affection of parents to be the reasons behind sudden aggressive behaviour at a later stage,? explains Sunita Kumar, a city-based psychologist. ?The pressure of excelling in games or academics forced upon children by parents tells a few years later,? she said.

What has perplexed psychiatrists further is the ?bizarre element? in these cases nowadays. A couple living in New Alipore wanted to commit suicide after they found it impossible to cope with their daughter?s constant demands for expensive gifts. The couple is undergoing anti-anxiety therapy.

In another case, a 14-year-old beat up his parents because he felt he was being pressured to do what he did not want to.

Another couple living in the Triangular Park area are on anti-depressants as their 10-year-old hardly talks to them.

The first bit of advice that psychiatrist Ranadip Ghosh Roy offered the couple was to discipline the child.

?The attention and affection that the child gets from parents and grandparents, not to mention the demands of becoming a Sachin Tendulkar, was reason enough for the child to build a cocoon around himself,? explains Ghosh Roy.

?We have started counselling parents, highlighting the fact that pressurising a child in his early years has harmful effects later,? he adds.

Neurologists, too, are getting a number of such cases these days, says Tapas Banerjee, head of the department (neurology) at the National Neurosciences Centre.