In 2014, the fifth edition of the (DSM-5) - one of the leading psychology bibles developed by the American Psychiatric Association - announced it would no longer include hypochondriasis in its comprehensive list of psychiatric disorders.
The term, more colloquially known as hypochondria, has a history of sitting awkwardly between different categories of disorders: is it more anxiety, a depressive or personality disorder, or (a mental illness that causes bodily symptoms)?
The DSM-5 sought to make the definition clearer. It would now be divided into two alternative diagnoses: , and .
The authors also argued that hypochondria had taken on a pejorative connotation, and a diagnosis of it was hampering efforts to treat people who were experiencing varying levels of anxiety about their health.
In Australia, it is around 5.7 per cent of the population will be affected by health anxiety across their lifespan.
As looks into , what are these new definitions of hypochondriasis - and is there still a place for the term?
Illness Anxiety Disorder
DSM-5 authors that around 25 per cent of people who would formerly have been diagnosed with hypochondriasis fit the of Illness Anxiety Disorder (IAD).
IAD is likened more to general health anxiety: frequent thoughts and focus on one's physical health, accompanied by an unrealistic fear of developing severe disease.
It is generally associated with mild, if any, symptoms, with sufferers believing many sensations and body changes to be the sign of something more serious. These feelings can shift in nature, or be vague, will last for up to six months; any longer and the person may be diagnosed with Somatic Symptom Disorder (see below).
The anxiousness experienced with IAD can exacerbate physical sensations, leading to a cycle of symptoms and worry.
Insight guest Jean Flynn experiences this health anxiety, and says her concerns about her physical wellbeing can trouble her incessantly.
"When I do think I'm sick, [it causes me] a huge amount of anguish. A huge amount," she says.
"[I think about it] oh, every three and a half minutes, all day, all the time. I find it very difficult to distract myself. If I'm really in it and I think I've got something, it takes something big to really distract me from having the thoughts."
In the past, she's convinced herself she's had all manner of conditions.
"When I was about 22 I became convinced that I had MS ... I thought I had kidney disease, I didn't have that. I thought I had a brain tumour, didn't have that. I thought I had like a prolapse of the uterus, didn't have that."
Jean Flynn, on Insight Source: Insight
Somatic Symptom Disorder
With (SSD), sufferers are similarly highly focused on and anxious about their physical symptoms. These tend to be more extreme and inexplicable than those associated with IAD, involving feelings of pain or fatigue or more dramatic changes in body functions.
Significantly, these symptoms will often occur without medical explanation, and generally last for more than six months. DSM-5 authors people with SSD would make up about 75 per cent of those previously diagnosed with hypochondriasis.
People who experience SSD will exhibit extreme anxiety about their symptoms, which may interfere with their everyday lives. Mild symptoms can be read as a sign of something more serious, and there is a mistrust of test results. Visits to the doctor do not relieve stress, and there may be a lack of responsiveness to treatment and medication.
The differences between IAD and SSD are set out in the below .
Related to SSD is , a condition where bodily symptoms are thought to be caused by problems in the nervous system but no physical neurological cause can be found.
Source: Australia and New Zealand Journal of Psychiatry
Insight guest Miranda Licence has been diagnosed with FND, after suddenly finding herself unable to walk after going for a jog.
"It wasn't like I was paralysed, but I didn't know how to move," she says.
After investigations, her doctors discovered she wasn't completely unable to move; she could run. And walk backwards.
It seemed she had lost the automatic control of being able to walk, but the control of running and walking backwards had been retained, and could still be kick-started into action, speculates neurologist Dr Alex Lehn. 
Miranda Licence shares her story on Insight Source: Insight
Still a role for hypochondriasis?
While the DSM-5 is widely seen as a universal authority on mental disorders, some have argued its exclusion of hypochondriasis was premature, and a perhaps flawed decision.
"The division of the concept of hypochondriasis on the basis of the presence or absence of somatic symptoms lacks sound empirical support," Associate Professor Vladan Starcevic, of the University of Sydney and Nepean Hospital, following the DSM-5's release.
"The heterogeneity of hypochondriasis could have been addressed more adequately by creating the specifiers with predominant disease fear (phobia) and predominant disease belief (conviction)."
Associate Professor Starcevic also expresses concerns that shifting away from hypochondriasis to ameliorate its negative connotations may not ensure IAD and SSD do not also develop pejorative and stigmatising undertones.
He also notes that SSD has "attracted criticism, mainly because of its low diagnostic threshold and a possibility of unnecessarily using this diagnosis in the presence of serious medical conditions," while IAD could be incorporated into other anxiety disorders.
A recent confirmed the DSM-5's hypothesis that 75 per cent of former hypochondriasis diagnoses would meet the requirements for SSD, while the other 25 per cent would be classified as IAD. However, the study also found "no significant differences were found between SSD and IAD with regard to levels of health anxiety, other hypochondriacial characteristics, illness behavior, somatic symptom attributions, and physical concerns," and concluded the splitting of hypochondriasis appeared unwarranted.
Hypochondriasis remains in the most recent edition of the (ICD-10), which is a similar manual primary used in Europe.
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