mental disordsers: classification and epidemiology

What is a mental disorder?

A mental disorder is a condition characterised by alterations in thinking, mood, or behaviour that causes distress or impairment

What are the three main methods of classifying mental disorders?

By symptoms, by patterns/courses, and by assumed causes

What classification systems are commonly used for mental disorders

DSM-5 and ICD-10

What is the contemporary approach to classification of mental disorders

It uses operational definitions to specify how much of certain symptoms must be present to diagnose a disorder

What is the significance of research-based criteria in mental disorder classification

They ensure that diagnoses are grounded in empirical evidence rather than theoretical assumptions

What are some criticisms of the current classification systems for mental disorders?

• High rates of comorbidity

• Inconsistent dimensionality

• Transdiagnostic causes and treatments

• Conflicts of interest

• Focus on cross-sectional data

What does ‘point prevalence’ refer to in epidemiology

The proportion of people who have a disease at one specific point in time

What does ‘period prevalence’ refer to

The proportion of people who have a disease over a specified period, such as the last year or a lifetime

What is the estimated prevalence of mental disorders among men and women?

Approximately 15% for men and 20% for women

What does longitudinal research in New Zealand reveal about mental disorders

By age 11-15, 1 in 3 had a mental disorder, and by age 45, 86% had experienced one

What is the significance of comorbidity in mental disorders

Comorbidity is extensive, indicating that having one disorder increases the risk of developing other disorders

What are some early risk factors for mental disorders

Continuities and discontinuities across development, gene-environment interplay, and cumulative effects of early experiences

What is the ‘P-factor’ in mental health research

A general factor associated with the risk of various mental disorders, lower IQ, and cognitive decline

How does adolescent onset of mental disorders affect later outcomes

Adolescent onset predicts later disorders and a more diverse range of comorbidities

Why is it important to consider different developmental phases in mental health

Prevalence, presentation, assessment, and treatment of disorders may differ across developmental phases

What is a reason for age restrictions in diagnosing certain disorders

Some disorders, like Antisocial Personality Disorder (ASPD) can only be diagnosed in individual aged 18 and over

What pragmatic reasons affect the prevalence of mental disorders in different age groups

Sample dropout due to early mortality among those with certain disorders

What is the average life expectancy reduction for individuals with schizophrenia (SZ)

On average, individuals with schizophrenia have a life expectancy that is about 18 years lower than the general populations.

What is the typical onset age for schizophrenia

Schizophrenia usually has an onset in early adulthood

How does antisocial behaviour typically manifest across different ages

Antisocial behaviour tends to peak during the teenage years

What is the role of clinical interviews in diagnosing depression

Clinical interviews, such as the SCID, are used to assess symptoms of depression

What does the term ‘medicalisation’ refer to in the context of mental disorders?

The process of defining and treating normal behaviours as medical issues, potentially leading to over-diagnosis

What is the biggest difference in weight gain between teens and adults

3.7% for adults versus 40.5% for teens

What is the biggest difference in weight loss between adults and teens?

7.4% for adults versus 31.4% for teens

What is the age range for infancy and early childhood

Up to age 5

What is the age range for childhood

5 to 12 years

What is the age range for adolescence and early adulthood

12 to 25 years

What is the age range for adulthood to middle age

25 to 65 years

What is the age range for older age

65 years and older

What are some common externalising problems in children

Neurodevelopmental disorders and anxiety disorders

What mental health disorders are rare or nonexistent in childhood

Schizophrenia, bipolar disorder, and personality disorders

What are key markers of normative vs problematic behaviour in children

Severity, persistence, pervasiveness, and type of behaviour

What are some developmental challenges faced during adolescence

Peers, school, puberty, and sexual experiences/relationships

At what age do sex differences in depression first emerge

Around age 18

What are some mental health challenges faced in early adulthood

Onset of disorders and challenged of entering the workforce and leaving home

What is a common issue in mental health during middle age

Comorbidity with physical health problems

What can trigger new-onset mental health problems in middle-ages individuals

Menopause

Why are severe mental disorders relatively rare in old age

Due to earlier mortality of those with severe disorders and difficulty in identifying symptoms

What is the diagnostic criteria for ADHD in very young children

At least 36 months old, must present with at least 6 out of 9 signs of hyperactivity and/or inattentiveness, causing significant impairment for at least 6 months

What is OAD and its diagnostic criteria

Overactivity Disorder in kids aged 24-36 months, requiring at least 6 signs of extreme hyperactivity and impulsivity without inattention

What are the tree types of Disruptive Behaviour Disorders (DBDs )

Noncompliance, temper loss, and agression

Why is situation psychopathologies within a developmental context important

It helps determine if behaviours is inconsistent or maladaptive

What percentage of preschoolers with ADHD meet criteria for another disorder

90%

What percentage of kids with ADHD had been suspended at least once in preschool study

40%

What are the concerns regarding diagnosing mental disorders in young children

Worries about labelling a child versus the benefits of early intervention and questions about the stability of diagnosis

What is considered a developmental impossibility for preschoolers

Forcible sexual activity

What is an example of developmental improbability in preschoolers

Stealing with confrontation

What is the significance of observing preschoolers behaviour

Observation captures qualitative differences in behaviour that distinguish atypical from typical behaviour

What are the three components of behaviour modulation

1. Intensity of behaviour (strength and force)

2. Flexibility of behaviour (stubbornness and lack of modifiability)

3. Organisation of behaviour (predictability and regulation)

How does context affect expectability of behaviour in preschoolers

Mild aggression towards peers may be expected, while aggression towards adults is not

What percentage of preschoolers were classified as disruptive based on observational checklists

23% disruptive

What were the findings regarding noncompliance among different groups of preschoolers

Disruptive and sub-clinical groups had significantly more clinically concerning noncompliance compared to non-disruptive

Which groups showed significantly more temper loss

The disruptive group

What type of aggression was more common in the disruptive group

Aggression towards objects

What does pervasiveness refer to in the context of preschool behaviour

The generalisation of problematic behaviour across different context

What is the relationship between clinically concerning behaviours and impairments

Clinically concerning passive noncompliance, temper loss, and aggression were associated with increased risk of impairment

What was the role of maternal reports in predicting impairments

Maternal reports of daily frequency predicted impairment for all behaviours except destructiveness

What did the study conclude about direct observation of behaviour

It provided insights into typical vs disruptive behaviour and added value beyond parent report in predicting impairment

What is the acceptable diagnostic stability percentage for ASD diagnosis made at age 2

80% ASD stability at 2

What might explain why some children diagnosed with ASD later do not meet criteria

They may have moved to another developmental disorder like language delay or global developmental delay

What is a common characteristic of psychiatric genetic profiles

Every individual has a genetic risk for each psychiatric disorder, ranging form low to high

What is the nature-nurture debate’s relevance to mental illness

It is a false-dichotomy; mental illness is influence ]d by both genetic and environmental factors

What is the increased risk for first-degree relatives of individuals with Bipolar Disorder and Schizophrenia

6-10 times higher risk for BD & SZ

What are Genome-Wide Association Studies (GWAS) used for

Linking genetic variants to phenotypes by comparing frequency of variants in controls bvs cases

What is the implantation of most phenotypes being highly polygenic

They are influenced by thousands of common variants with minuscule effects meaning everyone has a risk for every disorder

What is the need for objective biomarkers in psychiatric genetics

To establish more precise diagnoses and treatment plans, similar to other medical fields

What is the average age of diagnosis for ASD currently

4 years ol average ASD diagnosis

What percentage of the sample diagnosed with ASD later did not meet criteria

Only 6%

What type of genetic variants have been implicated in various psychiatric disorders

Rare and de novo sequence variants and pathogenic CNVs

How do rare variants affect variability and risk of illness

They explain less variability but concur a substantially higher risk of illness due to their impact on protein expression or function

What is genetic pleiotrophy

Genetic variants are expected to influence more than one phenotype which may underlie comorbidity among disorders

What are three sources of genotype-phenotype associations detected in GWAS

1. Direst genetic effects (causal effect on phenotype)

2. Indirect genetic effects (influence through environment)

3. Confounding effects (e.g. assertive mating)

What is the significance of the dl-PFC in relation to risk genes

Risk genes are generally expressed globally in the brain, with the strongest expression in the dl_PFC

How does ADHD relate to genetic expression in the brain

ADHD is expressed in dopamingeric midbrain neuron’s, linking it to deficits in the reward system, motor control, and executive functioning

What is the relationship between genetic loading and ASD in females

Higher genetic loading is necessary to result in ASD in females, which may relate to the female protective effect

What is the correlation between risk for ASD and educational attainment

Risk for ASD is correlated with higher educational attainment

What are the four highly correlated groups of disorders identified in the notes

1. Compulsive behaviours (anorexia, OCD, Tourette’s)

2. Internalising symptoms (GAD, MDD)

3. Psychotic features (SZ, bipolar)

4. Neurodevelopmental disorders (ADHD, ASD, PTSD, substance abuse)

What limitations exists in strides of genetic overlap among disorders

The direction of causality is uncertain; variants may influence two phenotypes, affect one trait that influences another, or be falsely assumed to influence two traits

What is the current challenge in sing whole-genome sequencing clinically

Improving predictive accuracy and enabling discrimination between diagnoses to make it clinically viable

What percentage of variability in schizophrenia (SZ) has even the most well powered studies explained

Only 8.5% of variability in SZ

How do childhood and adulthood ADHD symptoms correlated

Childhood and adulthood ADHD symptom correlate at r= .81

What is the lowest genetic correlation observed between ADHD types

The lowest genetic correlation (r= .65) is between childhood and late-diagnosed ADHD

How do Bipolar I and Bipolar II correlate with other disorders

Bipolar II is correlated with MDD, while Bipolar I is more correlated with SZ

What is the functional impact of identifying specific causal variants

It helps in understanding the mechanistic basis of genetic risk and how variants influence biological processes

What role do environmental impacts play in genetic risk

The interact with genetic risk variants to influence biological factors like cell types, tissues, and developmental stages

What is the significance of drugs treating schizophrenia and depression in relation to genetic risk

They target proteins made faulty by specific risk SNPs

What is the implication of genetic risk for mental illness in relation to normality

Genetic risk for mental illness is not categorically distinct from normality

What is the relationship between parental behaviour and indirect genetic effects

Parental genetic variants can influence the individual through their behaviour, even is not transferred to the child

What is the impact of associative mating on genetic studies

It can confound the distribution of gene variants within populations

What is the importance of understanding the collective influence of genetic risk variants

It helps in comprehending how they interact with environmental factors to affect mental health outcomes

What is the average risk of developing schizophrenia (SZ)

1 in 100

What is the risk of developing schizophrenia if one parent had the disorder

8 in 100

What is the risk of developing schizophrenia if both parent s have the disorder

45 in 100

What is the risk of developing schizophrenia for siblings of affect individuals

9 in 100

What is the risk of developing schizophrenia for dizygotic (DZ) twins

17 in 100

What is the risk of developing schizophrenia for monozygotic (MZ) twins

40 in 100

What are some goals of psychiatric genetic research

Quantifying overall genetic influence, identifying specific genetic variants, studying gene-environment interplay

What are the two main approached to studying psychiatric genetics

Quantitative-genetic approaches and molecular-genetic approaches

What do quantitative-genetic approaches involve

Inferring genetic induces using methods like studying twins and adoptees.

What do molecular-genetic approaches involve

Measuring genetic variation directly, such as through genome-wide association studies (GWAS)