How long is grief supposed to last?

"The study of grief is first and foremost a study of love and of the attachments humans create in their lifetime," says psychiatrist and bereavement expert Colin Murray Parkes.

This love for those close to us doesn't disappear when they die, but in most cases, we learn to adapt, and the intense grief we experience at first becomes less pervasive over time.

For a subset of people however, getting over the death of a loved one is a struggle that lasts a long time and affects their day-to-day life on a long-term basis. They suffer from a condition known as prolonged grief disorder (or complicated grief).

"There isn't a definite timeline where we can say that this is now 'prolonged grief' we are dealing with. Grieving is quite an individual process," reveals Claudia Herbert, clinical psychiatrist and director of the Oxford Development Centre. "However, there has always been a recognition that for very cruel, unexpected or untimely deaths there can often be a traumatic grief reaction that goes on for longer and affects people more profoundly."

The growing body of research on the topic has opened the way for the disorder to be included in the World Health Organization's eleventh revision of the International Classification of Diseases (ICD-11), published later this year. However, many questions remain regarding prolonged grief disorder, its diagnosis and its treatment.

What is normal when it comes to grief?

First introduced in 1969, the Kübler-Ross model established by psychiatrist Elisabeth Kübler-Ross suggested that people go through five stages of grief after the death of a loved one. These are: denial, anger, bargaining, depression and acceptance.

Although this model has been very useful in trying to understand and characterise the complex emotional turmoil that goes with grief, it's also very important to recognise that different people grieve differently.

"Bereavement is a complex condition; you cannot really compare a woman who has lost a baby, an old man who has lost a wife, or parents who have lost their son in a car crash. All these people will obviously have different reactions and the social context they are in will also play a role," Murray Parkes says.

The point is there is no such thing as normal when it comes to grief, and the length of the grieving process. Everyone processes it in their own ways, depending on a range of factors, from the circumstances of the death to the support they receive.

Where prolonged grief differs is that it results in significant impairment to people's functioning and relationships, for a long period of time. Instead of gradually adapting over time, symptoms of acute grief remain.

Complicated grief is different from other psychiatric disorders such as depression or PTSD, although some of the symptoms overlap.

"There are different core symptoms of longing and preoccupation with the person who died in prolonged grief disorder, which you don't see in depression. Guilt and sadness are associated with the loss, whereas in depression, these feelings are more all-consuming, and the person sees themself and the world as bad," says Katherine Shear, professor of psychiatry at Columbia University, who has researched grief extensively.

Diagnosing prolonged grief

Some factors might make prolonged grief disorder more likely. They include whether the bereaved person has a past history of depression and anxiety, but in many cases, it's the nature of the relationship with the deceased which is crucial.

"Prolonged grief disorder is more likely after the loss of a first-degree relative, especially a spouse or a child. Other risk factors have to do with how the person died. A violent or sudden death, especially if it's that of a young person, is a risk factor," Shear says.

Treating complicated grief

Researchers have investigated the effects of both medication and psychotherapy when it comes to treating prolonged grief.

While some studies have suggested that SSRI antidepressants may help, other trials have found the medication has little effect.

Both group and individual grief therapy, with experienced grief counsellors, have been shown to be effective for people with complicated grief. Some of these interventions involve cognitive behavioural therapy (CBT), but alternative approaches also appear promising.

How to deal with complicated grief

Rely on your support network

Relying on your friends and family following a loss often proves pivotal for bereaved people.

It's important to recognise that people who are close to you can provide unique support; they know you well and can also raise the alarm if they feel you may need grief therapy.

"If as a friend or family member you start to notice the person has really changed since the loss, it would be very helpful to encourage them to seek support, and generally also to listen to the person without offering advice," Herbert says.

Don't be afraid to seek professional help

Sometimes, even your close relatives cannot help entirely. Speaking to a grief counsellor might help put words on the complex turmoil of emotions that arise after a loss - although making that step often feels difficult.

"Bereaved people often feel that other people may be more in need of help and may be reluctant to reach out. There can also be shame attached to them not feeling better sooner, as others often underestimate the effects of a severe bereavement. However, people who are bereaved should come forward; they should not be shy to seek treatment," Herbert explains.

In the UK, GPs can refer patients to counselling services, although you also have the option of contacting a grief counsellor on your own.

Contact charities and join support groups

Contacting a local support group or charity, and speaking to people who have gone through a loss as well can allow people to get out of the isolation that they often find themselves in after someone close dies.

When Erin Hope Thompson started the Loss Foundation after the death of her father, she was trying to fill a gap for her stepmother, who had expressed a need to speak to other bereaved people who had lost the love of their lives.

"Groups are more peer-focused; it's about normalising the grief, realising what you are feeling is okay and normal, and that other people might feel it too. Grief is still a taboo topic in our societies and can be isolating as people do not speak about it. Groups allow them to open up," Hope Thompson says.

Organisations like the Loss Foundation or Cruse Bereavement Care are found throughout the UK and offer very good support groups and resources for individuals to join. Charities dedicated to specific losses, such as Child Bereavement UK, for parents who have lost their children and for bereaved children, can also provide help that can be more adapted to people's circumstances.

Try different things, more than once

Don't hesitate to try different therapies or to join different support groups - and this goes for everyone, not just for people suffering from complicated grief.

"You never know what will help you process your grief before you give it a go. Something that might not work for you early on in the bereavement process may help you down the line, so don't be shy to try different kinds of support, at different points after the loss," Hope Thompson says.