That diagnosis is criticised as inappropriate by a leading psychiatrist and ''appalling'' by a well-known grief counsellor.

''There is a real risk of medicalising grief,'' Gordon Parker, a professor of psychiatry at the University of NSW, said. ''The concern is that health practitioners would be encouraged to reach for the prescription pad'' to give anti-depressants to people who were grieving normally, he said.

The new Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association, known as the DSM-5, puts too much focus on the similarities between major depression and grief and not enough on the important differences between them, Professor Parker said.

It was an ''appalling state of affairs'' that the manual seemed to reflect a widespread desire to suppress or deny powerful, natural human emotions and ''keep everything neat and tidy'', author and counsellor Petrea King said.

Pharmaceutical companies might be enriched, she suggested. ''If we can say that grief is a depressive illness, that is a huge pharmaceutical market'', considering ''pretty much everyone on the planet'' grieves at some stage of their life, Ms King said. Her Quest for Life Foundation is in partnership with Blackmores, which sells naturopathic health products.

A draft of the DSM-5 says grief can resemble a depressive episode in symptoms such as intensely sad feelings, deep and prolonged thinking about the loss, insomnia and weight loss.

But Professor Parker is concerned doctors who refer to the manual to assess patients will not see clear enough information about what makes grief and depression different. While people may feel an ache or sense of loss for the rest of their lives, intense grief is usually self-limiting in duration and lacks the feelings of low self-esteem and feelings of worthlessness, which are markers of depression, he said.

The management of grief, even when psychotherapy or counselling are involved, should not be the same as for depression, Professor Parker said. Grievers need to be allowed to unburden themselves and let out their pain, but depression needs a more interventionist approach to determine why the person has low self-esteem and to help them change negative thinking.

Treating grief as an illness would mean ''you are only medicating someone for a feeling, rather than giving them practical ways of living with that feeling'', Ms King said.

Professor Parker said there was a ''grey area'' where some people with severe and persistent grief ''will go on at a later stage to experience depressive symptoms''. But ''that depression is not necessarily the same as the clinical depression that warrants anti-depressants'', he said.