People’s judgments about whether they are depressed depend on how they believe their own suffering “ranks” in relation to the suffering of friends and family and the wider world, according to a new study.

Research from the Department of Psychology at the University of Warwick finds that people make inaccurate judgments about their depression and anxiety symptoms – potentially leading to missed diagnoses as well as false positive diagnoses of mental health problems.

This is of particular concern as vulnerable individuals surrounded by people with mental health problems may decide not to seek help because, compared to those around them, they perceive their suffering to be less severe than it actually is.

Conversely, those surrounded by people who feel depressed very rarely may incorrectly believe that their suffering is abnormal, simply because their symptoms appear to be more severe in comparison to others.

Researchers performed two experiments which found that people’s judgments of whether they were depressed or anxious were not mainly predicted by their symptoms’ objective severity - but by where they ranked that severity compared with their perception of others’ symptoms.

The study showed that participants’ beliefs about the distribution of symptoms in the wider population varied greatly.

For example ten per cent of participants thought that half the population felt depressed on at least 15 days a month, and ten per cent thought they felt so on two days or fewer a month.

Ten per cent of participants thought that half the population felt anxious on at least 26 days a month, whereas ten per cent thought they felt so on seven days or fewer.

Lead researcher Karen Melrose from the University of Warwick said: “It is the patient that initiates most GP consultations about depression and anxiety, so that personal decision to see a doctor is a vital factor in determining a diagnosis.

“Given that fact, our study may explain why there are such high rates of under and over-detection of depression and anxiety.

“Worryingly, people who could be the most vulnerable to mental health disorders – for example those from certain geographical areas of the country or demographic groups where depression and anxiety are high – could be the very ones who are at highest risk of missed diagnoses.

“This research could help health professionals better target information campaigns aimed at these groups.”

The paper, Am I Abnormal? Relative Rank and Social Norm Effects in Judgements of Anxiety and Depression Symptom Severity was published in the Journal of Behavioral Decision Making.