WHAT ARE INDIVIDUAL DIFFERENCES IN MENTAL HEALTH?

Individual Differences refers to variables that make one person different from another.
Some individual differences appear in the features of schizophrenia and the features of depression which describe who is most at risk from these disorders. Psychometric tests like the Beck Depression Inventory (BDI) and Public Health Questionnaire (PHQ) are also measuring individual differences.
Because this is such a huge topic, I'll confine comments to schizophrenia and depression. You don't need to know all this information, just enough points (say, 4) to offer some evidence for individual differences affecting mental health.

CULTURAL DIFFERENCES

Schizophrenia

Schizophrenia seems to occur all over the world and affects about 1% of the population. However, Bhugra et al. (1999) found that it there are differences between Asian and Whites:
  • Asians were more likely to neglect activities, lose appetite and commit suicide
  • More Whites reported auditory hallucinations

Black British people are more likely to suffer schizophrenia than any other ethnic group. This used to be blamed on migrants suffering stress and confusion in an unfamiliar culture, but the increased risk is still present in second generation Black British people. The British Institute of Psychiatry (2000) estimated Black people in the UK were 6 times more likely to develop schizophrenia than average.
McCabe & Priebe (2004) compared different explanatory models of illness among people with schizophrenia from four cultural backgrounds: African-Caribbeans, West Africans, Bangladeshis and Whites. They found that Whites cited biological causes more than non-White groups, who were more likely to give supernatural or religious reasons.

Therefore it is possible that ethnic minority groups aren't really suffering more schizophrenia - they're just more likely to be diagnosed with it. This might be because of:
  • Social explanations: Ethnic minorities experience racism and discrimination and are more likely to experience poverty - all risk factors for schizophrenia
  • Cognitive explanations: Some ethnic minorities - notably Africans and African-Caribbeans - express their thoughts and feelings differently from White patients, making them more likely to get a diagnosis of a severe mental disorder from a doctor
  • Biological explanations: Some ethnic minorities might have a genetic predisposition to schizophrenia. However, schizophrenia rates in Africa and the Caribbean are normal (around 1%), so that doesn't explain why the children of immigrants from those countries are more likely to develop the condition.
The tendency of mental health workers to treat Black patients in a racist way by diagnosing them with more severe conditions was exposed by Littlewood & Lipsedge in their 1982 book, Aliens & Alienists.

To get the joke in the title: an "alien" is someone from another place, like an immigrant, and an "alienist" is an old-fashioned term for a psychiatrist. Geddit????
Unipolar Depression

Clinical depression is also a worldwide problem but affects from 2% to 19% in different countries. This suggests factors like poverty and exposure to violence play a role in the onset of depression.

A cross-cultural study by Bromet et al. (2011) sampled 90,000 people in 18 countries. France and the USA were the most depressed and the poorer countries showed less rather than more depression. This supports the idea that depression is a disorder of Western nations, not just a psychological response to poverty, crime or war.
Worldwide prevalence of unipolar depression (2004): the darker red means more reported depression. This study shows the USA as the most depressed and Japan and Spain as the least - although India, Bangladesh and Pakistan are all in the top 5.
Geert Hofstede claims that individualist cultures are more prone to depression but collectivist cultures offer more support. This is backed up by a cross-cultural study by Chiao et al. (2009). Chiao suggests that people in Eastern countries have a greater genetic susceptibility to depression but have developed a collectivist culture as a way of reducing it; Westerners are less susceptible and have developed an individualistic culture, although this leaves them more at risk. This is using evolutionary psychology to explain culture and mental health.
However, India would usually be considered a collectivist culture and depression rates there are very high. Collectivist cultures put their own pressures on people to conform and feel shame and this can cause depression too. Another view would be that in collectivist cultures people are less willing to talk about depression, so it isn't diagnosed as often.
DEVELOPMENTAL DIFFERENCES
Schizophrenia

Schizophrenia may be classed as adolescent onset (10-17), early-adult onset (18-30), middle-age onset (30 -45) and late-onset (45+). The disorder does not suddenly “strike” and the obvious psychotic episode comes after less noticeable problems that might have existed for years. This makes it difficult to diagnose exactly when schizophrenia begins.

The peak period of onset seems to be from 15-30.

David Lewis (1996) claims children who later develop schizophrenia have 'premorbid' behavior (ie. unusual behaviour before they get ill) such as learning difficulties and behavioural problems. By age two, they are less likely to be walking and talking than other children.

Lindmer et al. (2001) found that patients with late onset schizophrenia are more likely to be female, with less negative symptoms and have a shorter period of illness.
Unipolar Depression

People are most likely to suffer their first depressive episode between  30-40 and there is a second, smaller peak of onset between 50-60.

Depression can be an effect of dementia in the elderly. It can also be caused by loneliness and social isolation which can happen in old age.

There is growing concern about depression in teenagers. Twenty years ago, depression in children was almost unknown. Now the fastest rate of increase in depression is among young people.  There are several explanations for this:
  • Social explanations: Young people experience more social pressure over appearance and popularity and, because of social media, they may experience cyberbullying
  • Cognitive explanations: Young people experience more confusion and anxiety over life choices (exam pressure, work and study opportunities, sexual orientation)
  • Biological explanations: Junk food, mobile phone emissions and sleep deprivation due to video games have all been linked to teen depression
"Children of the '90s" is a longitudinal study by the University of Bristol, which recruited 14,000 pregnant women in the early 1990s and follows their children and families. A recent analysis by Culpin et al. (2013) of 5,631 girls whose fathers left home when they were between 0 and 5 shows they are more at risk of depression than boys and also than girls whose fathers left when they were older (6-10).
These findings lend support to a Freudian view of depression, that it is a reaction to disturbed family relationships in early childhood - but that doesn't explain why the boys seem unaffected by the absent dads... although see below on why depression isn't diagnosed so much in males.
GENDER DIFFERENCES
Schizophrenia

Schizophrenia occurs equally in men and women. Kaplan et al. (1994) describe the peak ages of onset among men being between 15-25 years. The peak for women is 25-35 years but they also peak again in their 40s and 60s. Studies overwhelmingly support an earlier age of onset in males by 3-5 years, regardless of culture.

Men tend to display more negative symptoms. Women tend to display less irrational thinking but more affective symptoms (emotional problems like depression, hostility, impulsivity and inappropriate behaviour). Szymanski et al. (1995) found women were diagnosed more frequently with disorganized subtypes of schizophrenia than men.  Women were more likely to have delusions of persecution.
Unipolar Depression

Population studies have consistently shown clinical depression to be about twice as common in women as in men (Bebbington, 1996), although it is unclear why this is so. There are several possible explanations:
  • Social explanations: women experience greater social isolation (housewife, mother), poverty and domestic abuse
  • Cognitive explanations: women experience more stress and confusion over life choices (whether to pursue a career or raise children) and anxiety in society (fear of crime, sexism, etc)
  • Biological explanations: women's brains seem to have more serotonin receptors than men's brains (Jovanovic, 2008) and serotonin is a biological explanation for depression
As with cultural differences, it's also possible that women only appear to suffer this disorder more because they are more likely to be diagnosed with it. This is because in society it is more acceptable for women to talk about their feelings, which makes them more likely to present symptoms to a doctor. There is evidence that men express depressive feelings through drinking, aggression and work. Men are also more likely to commit suicide (Peter Orszag, 2015).
PERSONALITY DIFFERENCES
Schizophrenia
The most consistent personality traits are E (extroversion) and N (neuroticism).

High N  individuals are prone to mood swings and stress and easily feel anxious. High N scores have been linked with schizophrenia.

High E individuals are outgoing and crave excitement and this has been linked to the absence of schizophrenia (Van Os & Jones, 2001).

This means that the schizophrenic personality is a Neurotic (or Unstable) Introvert.
However, it's not clear whether this is explaining schizophrenia or just describing it. People with schizophrenia find it difficult to maintain social relationships and suffer mood swings so of course they score high for N and low for E.

Hans Eysenck also added P (psychoticism) to E and N to describe human personality. Psychoticism is "a halfway stage towards psychosis" (Heath & Martin, 1990). However, Eysenck uses P to describe criminals and psychopaths - and someone suffering a psychotic episode isn't necessarily one of those.
Eysenck is probably confusing psychotic and psychopathic - easily done since they sound similar! 'Psychotic' means a break from reality but 'psychopathic' means an inability to feel compassion or empathy for other people. People with schizophrenia are still compassionate people and are NOT psychopaths!
One of the other "Big 5" personality traits is Agreeableness (A) and people with depression score low on this too (McCann, 2010).

Low Conscientiousness (C) has also been linked to depression (Koorevaar et al., 2012).

But this too is only describing depressive symptoms, not explaining them.
Prospective longitudinal studies examine a cohort of people and monitor them over time to see if they develop a condition, then look for what they shared in common. De Graaf et al. (2002) followed 7076 Dutch adults for 12 months and those who developed mood disorders (including depression) had scored higher for N (neuroticism) than those who remained healthy. This suggests that personality traits (or at least N) might explain and predict depression rather than just describe it.
Unipolar Depression

High N (neuroticism) and low E (extroversion) are also linked to depression. However, as above, this may be just describing depression rather than explaining it: depressed people experience anxiety and they withdraw from social relationships, so of course they score high for N and low for E.
Brown et al. (1985) identify self-esteem as an important personality trait that acts as a protection against the onset of depression during stressful life events. However, they also identify situational variables that are just as important for protecting against depression, such as social support.

OTHER DIFFERENCES: CULTURE-BOUND SYNDROMES
ILLNESSES FROM AROUND THE WORLD

Culture-bound syndromes (or cultural disorders) are mental disorders which seem to affect a single cultural group. This means they are almost unknown outside of their own regions. They are sometimes called folk illnesses.
Faced with this baffling range of mental disorders around the world, psychologists used to think that it would be impossible to create a truly universal diagnostic system that could be applied internationally (like the ICD). However, Jane Murphy (1976) challenged this by demonstrating that many folk illnesses resembled Western mental disorders.

Murphy examined the Yorubas in Nigeria and a group of Inuit Eskimos in Alaska—groups that had no meaningful contact with modern culture. These tribes had names for disorders that appeared similar to schizophrenia, alcoholism and psychopathy. For example, the Inuit used the term “kunlangeta” to describe someone (usually a man) who lies, cheats and steals, is unfaithful to women and does not obey elders—very much like that of a Western psychopath.
The Eskimos has a way of dealing with a person suffering from kunlangeta: “somebody would have pushed him off the ice when no one was looking.”
CULTURE-BOUND SYNDROMES FROM AROUND THE WORLD
  • Amok (Malaysia): a minor insult triggers a homicidal frenzy; the sufferer remembers nothing afterwards
  • Ghost Sickness (Native Americans): dizziness and hallucinations blamed on evil spirits
  • Koro (China): compulsion to hold or bind the penis due to fear it is shrinking and will vanish
  • Latah (Asia): brought on by a sudden fright, the sufferer compulsively imitates other people or animals
  • Mal de oro (Hispanics): "the Evil Eye" causes vomiting, fever and diarrhoea in children and sometimes adults
  • Ode-ori (Nigeria): sensation of insects crawling inside your head, usually with paranoia about evil spirits
  • Taijin kyofusho (Japan): Terror of offending other people with your body odour
However, not all cultural disorders "translate" into Western disorders this easily. There are some (like Mal de oro) which seem to mix symptoms from different conditions and others (like Amok ) which are in a category of their own.
For example, Koro is characterized by delusions of penis shrinkage; the sufferer panics and becomes convinced that when the penis vanishes, they will die. This idea makes sense in terms of Chinese culture, which emphasizes the healthy balance of "yin" and "yang" - masculine and feminine energies in the body and soul. Acts considered abnormal in Chinese culture (such as visiting prostitutes or masturbation) disturb the yin/yang balance.
In terms of Western medicine, this might be hypochondria or a psychotic episode, brought on by sexual shame, but it only makes sense for believers in Chinese philosophy.

Koro is also thought to be transmitted through food. In 1967, there was a koro epidemic in Singapore after newspapers reported cases of koro due to eating pork from a pig that had been given a drug against swine fever. Nearly 500 cases of koro were reported over 10 days.

Are there Western culture-bound syndromes? Anorexia nervosa has been suggested as a disorder which only affects people in Western cultures (but the study by Becker et al. argues it is learned from TV role models); Dissociative Identity Disorder (DID - multiple personality disorder) seems to affect only Americans and Europeans.

APPLYING INDIVIDUAL DIFFERENCES TO MENTAL HEALTH
AO2

Diagnosing Cultural Disorders
DSM-IV introduced an appendix listing 25 culture-bound syndromes. ICD-10 lists 12 types of culture-bound syndrome.
This was seen as an advance back in 1993 for DSM to acknowledge there were mental disorders outside of America. However, the list was pretty arbitrary and was described as "a cabinet of curiosities" (Cummings, 2013). The ICD-10 list is also rather arbitrary - why is Wendigo in it (a Native American illness that makes people think they are turning into a cannibal) but not Mal de oro?
DSM-5 replaced this list with a section on "Cultural Concepts of Distress". This analyses cultural disorders in three ways:
  • Cultural syndromes: “clusters of symptoms and attributions that tend to co-occur among individuals in specific cultural groups, communities, or contexts . . . that are recognized locally as coherent patterns of experience”
  • Cultural idioms of distress: “ways of expressing distress that may not involve specific symptoms or syndromes, but that provide collective, shared ways of experiencing and talking about personal or social concerns”
  • Cultural explanations of distress or perceived causes: “labels, attributions, or features of an explanatory model that indicate culturally recognized meaning or etiology for symptoms, illness, or distress”
A "syndrome" is a collection of symptoms that tend to occur together, whether or not they have the same cause. Schizophrenia and unipolar depression would both be syndromes. "Cultural syndromes" recognises that, in other cultures, the symptoms of depression and schizophrenia might cluster together in different ways, so that they initially seem like a different disorder.

"Idioms" are local ways of expressing things. Some cultural disorders only seem different from Western disorders because people in other cultures have a different way of expressing their feelings.

"Cultural explanations" are like the explanatory models of schizophrenia studied by McCabe & Priebe (2004).  People who think their disorder is caused by witchcraft or yin-yang imbalance will behave differently from people who believe it's caused by neurotransmitters or hormones.
This new approach by DSM-5 has been praised because it makes it more likely a psychiatrist will diagnose a patient from a different culture accurately instead of dismissing their unfamiliar symptoms as meaningless.

EVALUATING INDIVIDUAL DIFFERENCES IN MENTAL HEALTH (AO3)
SWAC

Strengths

These ideas account for the huge variety in symptoms and outcomes from mental disorders. In order to make a helpful diagnosis, a psychiatrist must take into account age and gender and especially culture.

In the past there has been a tendency to assign severe diagnoses like schizophrenia to people from ethnic minorities who show symptoms that are odd in Western culture (like talking out loud to dead relatives). Littlewood & Lipsedge (1982) exposed this diagnosis of "West Indian Psychosis" as no more than medical racism.

Since then, the DSM has started including cultural disorders and the DSM-5 goes to great length to encourage doctors to analyse patients' symptoms and recognise a familiar disorder behind unfamiliar idioms of distress or cultural explanations. It also recognises that, in some cultures, syndromes like depression and schizophrenia present different symptoms.

This makes false diagnosis less likely, which is particularly good news for ethnic minorities who are less likely to be ignored (false negative) or given unnecessary medication (false positive).

Weaknesses

The tendency to treat cultural disorders as "disguised forms" of Western disorders is ethnocentric. It can lead to false diagnosis if a cultural disorder is in fact a separate condition of its own - and a false diagnosis leads to inappropriate treatment.

Focusing too much on individual differences can sometimes obscure things that people share in common. Even though depression is rare in children, it does occur (and may be increasing) and believing that a child's condition cannot be clinical depression because of age might lead to a false negative diagnosis.

Similarly, men and women have more in common than not, and women can develop schizophrenia earlier in life and men later in life. Bradshaw's case study of Carol is about a young woman who developed schizophrenia in her late teens/early 20s, which is a time period more associated with men.

Applications

Individual differences can lead to better diagnoses if they are borne in mind, but can interfere with diagnosis if they are taken too far. The  tries to get the balance right."Cultural Concepts of Distress" chapter in DSM-5 tries to get the balance right. ICD-10 has a lot of catching up to do in its next revision.

Personality testing might be useful for screening hospital patients to see who is most at risk of developing depression or schizophrenia, so long as it is remembered that patients who are not Neurotic Introverts can develop these conditions too.

Comparisons

The big debate is over whether individual differences really influence mental health or whether they are an "artifact" - an "artifact" is a human creation. For example, are women really more depressed than men, or are they just more likely to go to the doctor and get diagnosed with depression than men?

This touches on a lot of debates in Psychology. Positivists, who believe in the scientific status of Psychology, would argue that these differences are real and point to the greater number of serotonin receptors in the female brain. They might also argue that some ethnic groups suffer from mental disorders for scientific, biological reasons.

This viewpoint easily leads to stereotyping, sexism and racism. The Anti-Positivist view is that people are all the same, but that society treats them differently. Because society is sexist, many of the abnormal and dysfunctional things that men do (fighting, crime, getting drunk) are not viewed as mentally ill, but when women - or men from ethnic minorities -  behave strangely, they are diagnosed as ill.

EXEMPLAR ESSAY
How to write a 8-mark answer

Evaluate the importance of individual differences in understanding mental health. (8 marks)
  • A 8-mark “evaluate” question awards 4 marks for describing factors (AO1) and 4 marks for AO3 (Evaluate). Don't forget to add a conclusion so that you can get into the top band (7-8 marks).

Description
Individual differences are things that make people distinctive, like their age and sex and education. It includes personality types that may be especially prone to mental disorders
Cultural disorders are mental disorders that only seem to happen in one country or among one ethnic group.
An example of a cultural disorder is koro, which affects Chinese men who become convinced their penis is shrinking and they are going to die.
Asian men also show different symptoms of schizophrenia, such as loss of appetite and suicidal ideas, according to Bhurgra et al.

Evaluation
Individual differences are backed up by lots of studies. For example, the 'Born in the '90s' longitudinal study shows girls whose fathers leave home when they are infants are more at risk of depression.
However, figures like this could be an artifact, because girls are more likely to be given a diagnosis of depression than boys with the same condition.
There is a growing recognition that culture affects mental illness. The DSM-5 introduces the idea of "cultural idioms of distress", because different cultures express themselves in different ways.
On the other hand, there's still a tendency to treat ethnic minorities differently, which might be why schizophrenia is 6 times higher in Black British population,

Conclusion
DSM-5 is moving towards a less ethnocentric approach to mental disorders but ICD-1-0 (used in Britain) still lists a dozen culture-bound syndromes as "curiosities".
  • Notice that for a 8-mark answer you don’t have to include everything about individual differences in mental health. I haven’t mentioned age or detailed personality or the other cultural disorders But I have tried to make the two halves – Summary and Evaluation– evenly balanced.