Te Rau Hinengaro: The New Zealand Mental Health Survey

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Te Rau Hinengaro: The New Zealand Mental Health Survey
Key results

Chapter 2: Prevalence and Severity across Aggregated Disorders
J Elisabeth Wells

The prevalence of disorder depended on the time period involved: 39.5% of the population had met criteria for a DSM-IV mental disorder at some time in their life before the interview, 20.7% had experienced disorder within the past 12 months and 11.6% in the past month.
Those with disorder in the past 12 months (20.7%) were classified by severity of disorder during that period.
The prevalence of serious disorder was 4.7%, moderate disorder 9.4% and mild disorder 6.6%, with the remaining 79.3% of the population not diagnosed with a disorder.
A mental health visit in the healthcare sector (mental health and general health) was made in the past 12 months by 58.0% of those with a serious disorder, 36.5% with a moderate disorder, 18.5% with a mild disorder and 5.7% of those not diagnosed with a disorder.
The prevalence of disorder and serious disorder in the past 12 months was higher for younger people, people with less education, people with less income and people who lived in more deprived areas.
In contrast, the sociodemographic correlates had little relationship to the percentage who made a mental health visit in the health sector in the past 12 months, after adjustment for severity. Differences were generally small and non-significant, with no clear gradients across age, income or deprivation.
Māori and Pacific people had a higher prevalence of disorder and serious disorder in the past 12 months than was found for the Other composite ethnic group, but these differences were much reduced, particularly for Pacific people, after adjustment for sociodemographic correlates (the adjusted prevalence of disorder for Māori, Pacific and Others was 23.9%, 19.2% and 20.3% respectively). Both Māori and Pacific people were less likely than the Other group to access treatment when severity was taken into account (9.4%, 8.0% and 12.6% respectively).

Chapter 3: Twelve-month Prevalence
J Elisabeth Wells

Anxiety disorders were the most common group of disorders in the past 12 months (14.8%), followed by mood disorders (7.9%), then substance use disorders (3.5%), with eating disorders the least common group (0.5%). Within each group the prevalence of individual disorders varied several-fold.
Nearly all disorders were most common in the group aged 16–24 and prevalence declined across older age groups. This trend was most marked for substance use disorders. Anxiety disorders and major depressive disorder were more common in females, dysthymia and bipolar disorder occurred equally for females and males, and there was a clear male predominance for substance use disorders.
Specific phobia produced the least interference with life, and mood disorders produced the most interference. Case severity, which included the impact of a disorder and comorbid disorders, was predominantly serious or moderate for all disorders.
Unadjusted prevalences, which show the burden of disorder, were generally highest for Māori, intermediate for Pacific people and lowest for the Other composite ethnic group. After adjustment for age, sex, educational qualifications and equivalised household income the results were as follows: there was no difference across the ethnic groups in the prevalence of anxiety disorders; Pacific people had the lowest prevalence of major depressive disorder (3.5%) while Māori and Others had very similar prevalences (5.7% and 5.8%); Māori and Pacific people had a higher prevalence of bipolar disorder (3.4% and 2.7%) than Others (1.9%); and Māori (6.0%) had a higher prevalence of substance use disorders than Pacific people (3.2%) or Others (3.0%).

Chapter 4: Lifetime Prevalence and Lifetime Risk of DSM-IV Disorders
Mark A Oakley Browne

It is common for a person to experience a mental disorder at some time in their life, with 39.5% of people aged 16 and over meeting criteria for a disorder at some time before interview.
The lifetime prevalence estimates for disorder groups are: anxiety disorders, 24.9%; mood disorders, 20.2%; substance use disorders, 12.3%; and eating disorders, 1.7%.
Most people first experience their disorder early in their lives. Half of all cases have started by age 18 and three-quarters by age 34. The median age of onset of a disorder is 13 years for anxiety disorders, 31 years for mood disorders, 18 years for substance use disorders, and 17 years for eating disorders.
The estimated lifetime risk at age 75 for any disorder is 46.6%, which is 7.0% higher than the observed lifetime prevalence. By disorder group, the estimated lifetime risks are: anxiety disorders, 28.8%; mood disorders, 28.4%; substance use disorders; 13.8%; and eating disorders, 1.9%.
More recent cohorts have higher prevalences of any disorder than earlier cohorts. Compared with the group aged 65 and over, the other age groups have significantly higher hazard ratios for lifetime anxiety, mood, substance use and eating disorders (p < .0001 for all comparisons). A gradient exists across the age groups, with younger age groups having higher hazard ratios than older groups.
Females have higher prevalences of anxiety, mood and eating disorders than males. Males have higher prevalences of substance use disorders than females. With adjustment for ethnicity and age, females compared with males have higher hazard ratios for lifetime anxiety disorders, mood disorders, eating disorders and any disorder. Males have higher hazard ratios for lifetime substance use disorders compared with females.
When adjustment is made for age and sex, Māori have significantly higher hazard ratios for lifetime risk of all disorder groups compared with the Other composite ethnic group. Māori also have higher hazard ratios for lifetime mood disorders and substance use disorders compared with Pacific people. Pacific people have higher hazard ratios for lifetime substance use disorders and eating disorders compared with Others.

Chapter 5: Comorbidty
Kate M Scott

Mental disorder comorbidity

Some experience of mental disorder is widespread in the community (affecting 20.7% of the population), and while most (63%) people who experience a 12-month mental disorder have only one disorder, a sizeable group (37%) have more than one.
Much of the burden of psychopathology (61.4% of all 12-month disorders) is carried by a small proportion of the population (7.7%) who experience multiple disorders.
Mood and anxiety disorders commonly co-occur; by comparison, substance use disorders are less frequently comorbid with other categories of disorder. Comorbidity between substance use disorders was common, however, with 45.3% of those with a drug use disorder also meeting criteria for alcohol abuse and 30.7% meeting criteria for alcohol dependence.
A clear relationship exists between the increasing number of disorders and case severity, with 59.6% of people experiencing multiple disorders classified as serious cases.
A clear association exists between an increasing number of disorders and suicidal behaviour, especially suicide attempts.
The more disorders experienced, the greater the likelihood of accessing health services of all kinds, particularly specialist mental health services.

Mental–physical comorbidity

People with mental disorders have higher prevalences of several chronic physical conditions; namely, chronic pain, cardiovascular disease, high blood pressure and respiratory conditions. The prevalence of chronic disease risk factors is also higher among people with mental disorders.
People with chronic physical conditions generally experience a higher prevalence of mental disorders compared with people without physical conditions.
The sex difference in the prevalence of mental disorder in our survey (with females having a higher prevalence than males) is wider for people with some chronic conditions (cardiovascular disease and diabetes) compared with people without those chronic conditions.

Chapter 6: Disability
Kate M Scott

Three percent of the population reported days completely out of role due to mental health problems in the past month, with at least 7.8%–8.2% reporting partial role impairment due to mental health problems.
Mood disorders are associated with more role impairment than anxiety or substance use disorders.
Experiencing multiple mental disorders at the same time greatly impairs role functioning.
Mental disorders and chronic physical disorders are generally associated with similar degrees of disability.
The combination of mental and physical disorders is more disabling than either disorder alone.

Chapter 7: Suicidal Behaviour
Annette Beautrais

Lifetime prevalences for suicidal behaviours were: suicidal ideation, 15.7%; suicide plan, 5.5%; suicide attempt, 4.5%.
Lifetime prevalences for suicidal behaviours were consistently significantly higher in females than males (ideation: females, 17.4%; males, 14.0%); plan: females, 6.4%; males, 4.6%; attempt: females, 5.6%; males, 3.4%).
Median ages of onset for all three behaviours were in the twenties: suicidal ideation, 25 years; making a suicide plan, 25 years; suicide attempt, 21 years.
The prevalences for suicidal behaviour in the past 12 months were: suicidal ideation, 3.2%; suicide plan, 1.0%; suicide attempt, 0.4%.
The risk of suicidal ideation in the past 12 months was higher in females, younger people, people with lower educational qualifications, and people with low household income, and among people living in more deprived areas (measured using the small area descriptor of socioeconomic adversity, the New Zealand Index of Deprivation) and in urban areas. The risk of making a suicide plan or attempt was more common among younger people, people with low household income and people living in more deprived areas. The risk of making a suicide attempt was higher in people in urban areas.
The risk of suicidal ideation, suicide plan and suicide attempt varied with ethnicity, with Māori and Pacific people reporting higher rates of suicidal behaviour than the Other composite ethnic group (ideation: Māori, 5.4%; Pacific, 4.5%; Other, 2.8%; plan: Māori, 1.8%; Pacific, 2.6%; Other, 0.8%; attempt: Māori, 1.1%; Pacific, 1.2%, Other, 0.3%). However, after adjustment for sociodemographic factors there were no ethnic differences in ideation, although Māori and Pacific people still had elevated risks of suicide plans and suicide attempts.
Individuals with a mental disorder had elevated risks of suicidal behaviour, with 11.8% of people with any mental disorder reporting suicidal ideation, 4.1% making a suicide plan and 1.6% making a suicide attempt.
Mood disorders, anxiety disorders, eating disorders and substance use disorders were all associated with suicidal ideation, suicide plan and suicide attempt.
Almost half of those with a 12-month history of suicidal ideation, suicide plan or suicide attempt did not report making any general medical or specialist mental health visits within the same 12-month period in which they were suicidal.

Chapter 8: Health Services
Mark A Oakley Browne, J Elisabeth Wells

There is a significant unmet need for treatment for people with mental disorders. Of all 12-month cases of mental disorder, 38.9% had a mental health visit to a health or non-healthcare provider in the past 12 months. Of these 12-month cases, 16.4% had contact with a mental health specialist, 28.3% with a general medical provider, 4.8% within the human services sector and 6.9% with a complementary and alternative medicine (CAM) practitioner.
Of the total population, 13.4% had a visit for a mental health reason in the 12 months before the interview.
In all treatment sectors, over 50% of contacts involved between one and five visits. However, in the mental health and CAM sectors, a small minority of people accounted for a substantial proportion of the total number of visits.
The majority of people who had mental health visits reported they were ‘very satisfied’ or ‘satisfied’ with the treatment received. The majority of people who had treatment perceived that treatment as helping ‘a lot’ or ‘somewhat’.
Unmet need for treatment was greatest in younger people and Pacific people. People with lower educational attainment and people resident in rural centres or areas had lower rates of visits to the mental health specialty sector. Unmet need for treatment did not vary significantly by socioeconomic status.
Most people with lifetime disorders eventually made contact before their disorder ended, with proportions making contact varying from 55.7% for posttraumatic stress disorder to 99.5% for alcohol dependence. However, the percentages seeking help at the age of onset were small for most disorders and several disorders had large percentages who never sought help.
The median duration of delay until contact varied from one year for major depressive disorder to 38 years for specific phobias.
The most commonly endorsed reasons for delaying seeking, stopping treatment early, or not seeking help were attitudinal (such as ‘I thought the problem would get better by itself’).

Chapter 9: Māori
Joanne Baxter, Te Kani Kingi, Rees Tapsell, Mason Durie

Te Rau Hinengaro surveyed 2,595 Māori individuals, and captured the diversity of Māori across a range of demographic, social, economic and cultural indices.
The prevalence of mental disorders in Māori was 50.7% over their lifetime (before interview), 29.5% in the past 12 months and 18.3% in the previous month.
The most common 12-month disorders among Māori were anxiety disorders (19.4%), mood disorders (11.4%) and substance use disorders (8.6%). The most common lifetime disorders among Māori were anxiety disorders (31.3%), substance use disorders (26.5%), mood disorders (24.3%) and eating disorders (3.1%).
Lifetime prevalence of any disorder was highest in Māori aged 25–44 (58.1%) and lowest in those aged 65 and over (22.7%). The lifetime prevalence of disorder among Māori females was 52.7% and among Māori males was 48.4%.
In Māori with any 12-month disorder, 55.5% had only one disorder, 25.7% had two disorders and 18.8% had three or more disorders.
Among Māori with any 12-month disorder, 32.5% had some contact with a provider of services. This was divided among mental health specialist services (14.6%), general medical services (20.4%) and non-healthcare providers (9.1%).
Of Māori with any mental disorder, 29.6% had serious disorders, 42.6% moderate disorders and 27.8% mild disorders. Health care contact increased with severity. Of Māori with serious disorder 47.9% had some contact with health services compared with 25.4% of those with moderate disorder and 15.7% of those with mild disorder.
Lifetime suicidal ideation was reported by 22.5% of Māori, with 8.5% making suicidal plans and 8.3% making suicide attempts. Māori females reported higher rates of suicidal ideation, suicide plans and suicide attempts compared with Māori males across lifetime and 12-month periods.
Compared with Pacific people and the Other composite ethnic group (ie, non-Mäori non-Pacific), a higher proportion of Māori had 12-month anxiety, mood, substance use and eating disorders. After adjusting for age, sex and socioeconomic correlates, differences remain between Māori and Pacific people for mood disorders and substance use disorders and between Māori and Others for substance use disorders.

Chapter 10: Pacific People
Siale Foliaki, Jesse Kokaua, David Schaaf, Colin Tukuitonga

A total of 2,374 Pacific people were interviewed: 49.2% were Samoan; 20.7% were Cook Island Māori; 16.5% were Tongan; and 17.5% were other Pacific peoples.
Pacific people experience mental disorders at higher levels than the general population. Twenty-five percent of Pacific people had experienced a mental disorder in the past 12 months and 46.5% had experienced a disorder at some stage during their lifetime.
In the 12 months before the survey, 16.6% of Pacific people experienced a single disorder, 5.1% experienced two disorders and 3.3% experienced three or more disorders.
Of Pacific people who experienced a mood disorder, 34.9% also experienced an anxiety disorder and 16.8% a substance use disorder. Of Pacific people who had a substance use disorder, 27.6% also had a mood disorder and 41.8% an anxiety disorder.
Within the past 12 months, 5.9% of Pacific people had a serious disorder, 11.6% had a moderate disorder and 7.6% had a mild disorder.
Pacific people had lower rates of mental health visits compared with other ethnic groups. Within the past 12 months, 25.0% of Pacific people with serious disorder had a mental health visit in the healthcare sector. The total New Zealand population with serious disorder was twice as likely to have had a mental health visit in the healthcare sector (58.0%).
Of Pacific people aged 16–24 and 25–44, 21.1% and 20.4% respectively reported suicidal ideation over their lifetime. A suicide attempt within their lifetime was reported by 4.8% (almost 1 in 20) of Pacific people. In the past 12 months, 4.5% of Pacific people reported suicidal ideation, with 1.2% of Pacific people having made a suicide attempt.
Of New Zealand-born Pacific people, 31.4% had a 12-month prevalence of any mental health disorder compared with 15.0% of Pacific people who migrated after the age of 18.

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