Psychological disorders: diagnosis, DSM, and epidemiology
Mental health, mental health problems, and mental disorders
Mental health: a state of emotional and social well-being in which individuals realize their own abilities, can cope with normal stresses of life, can work productively, and can contribute to their community.
Mental health problems: a wide range of emotional and behavioural abnormalities that affect people across life; exist on a spectrum including cognitive impairment and disabilities, phobias, panic attacks, drug-related harm, anxiety, personality disorders, depressive disorders, and psychosis.
Mental disorders: clinically recognisable sets of symptoms and behaviours that usually require treatment to alleviate; a serious departure from normal daily functioning.
Key distinction: mental disorders severely impact daily life (cognitively, emotionally, socially) compared with mental health problems which may not, by themselves, constitute a disorder.
If symptoms align with mental health problems and impair daily life, a psychologist may be involved for treatment.
Providers:
Psychologists diagnose/treat clients with mental health issues (clinical or generalist psychologists depending on qualification).
Psychiatrists are medical professionals who can prescribe medications.
Initial assessment: clinical interview and DSM guidance
Clinician role: the psychologist administers a clinical interview, asking about current symptoms and history (e.g., onset, duration, frequency).
Important diagnostic question: do symptoms impact day-to-day functioning?
DSM definition: disorders are characterised when symptoms impair social and occupational functioning.
Anxiety example: anxiety is a disorder only if it co-occurs with several other symptoms and severely affects functioning.
DSM reference: a diagnostic framework; clinicians check whether reported details meet DSM symptom criteria.
Example scenario: client reports sleep problems, social withdrawal, flattened mood → clinician may consult Major Depressive Disorder criteria in the DSM.
Note on information gathering:
Some clients lack insight or cannot express symptoms; psychologists may need additional methods to gather information.
Hypothesis testing: clinicians probe for more information to reveal additional symptoms, while avoiding pressure that could lead to false reporting.
Collateral information: data from family, friends, GPs, teachers, etc.
Confidentiality: collateral information only with client’s permission.
DSM classification system and updates
DSM = Diagnostic and Statistical Manual of Mental Disorders; used to diagnose based on syndromes and categories.
Current editions: DSM-5 and DSM-5-Text Revision (DSM-5-TR).
DSM updates: periodically updated to reflect new information; symptoms may be removed or disorders reclassified as understanding evolves.
Examples of changes from DSM-IV to DSM-5:
Bereavement removed from Major Depressive Disorder criteria.
Binge eating disorder added to feeding and eating disorders category.
Body dysmorphic disorder reclassified from somatoform disorders to the Obsessive-Compulsive Disorder (OCD) category due to shared features such as appearance-related obsessions and related compulsions (e.g., mirror checking).
March 2022: APA released DSM-5-TR.
Prolonged grief disorder added as a new diagnosis (replacing bereavement context).
Improved coding for insurance claims.
Cultural, racial, ethnic factors and gender inclusivity updated (e.g., terminology changes: cross sex medical procedure → gender-affirming medical procedure; natal male/native female → individual assigned male or female at birth).
Ongoing consideration of sociocultural and genetic factors in disorder causation for a more holistic framing.
Psychometric assessment in diagnosis
After gathering information and applying DSM criteria, clinicians use validated psychometric tools to assess symptom severity.
Examples of validated tools (with revisions):
Beck Depression Inventory (BDI), currently in revision as BDI-2.
Eating Disorders Inventory (EDI), currently up to revision 3 (EDI-3).
Social Phobia and Anxiety Inventory (SPAI).
There are many validated scales to quantify symptom severity and track changes over time.
When are symptoms classified as a psychological disorder?
Syndrome: a group of associated features.
Diagnostic criteria: clinically significant disturbance in cognitions, emotion regulation, or behavior reflecting dysfunction in underlying psychological, biological, or developmental processes.
Not a disorder if the response is an expectable or culturally accepted reaction to stressors or loss (e.g., grief following bereavement).
Bereavement issue: bereavement was removed from Major Depressive Disorder in DSM-IV/DSM-5, but the DSM-5-TR reinstated a related condition (Prolonged Grief Disorder) as a separate consideration.
Social deviance/general conflict with society: not a disorder unless deviance stems from a preexisting dysfunction that has not yet been diagnosed; other historical cues may also indicate issues.
Why classify disorders? Pros and cons
Pros of classification:
Facilitates communication between psychologists and with clients about symptoms and their interpretation.
Aids communication in research and understanding causality.
Supports treatment selection within the scientific-practitioner model (evidence-based treatments).
Enables comparisons across time and geography (epidemiology, public health planning).
Cons and caution:
Categorical vs dimensional debate: many disorders exist on a spectrum; individuals rarely present with identical symptom profiles.
DSM-5-TR introduced a dimensional approach to rate severity along a continuum for some conditions.
Pejorative labels and stigma: labels can influence self-perception and behavior (self-fulfilling prophecy) but can also provide closure for some individuals.
Reliability concerns: risk of low inter-rater reliability if clinicians diverge in diagnoses even with the same manual.
Cultural differences: some assessment tools were developed on predominantly white samples; not all tools are culturally appropriate.
Treating cultural syndromes and delivering culturally sensitive care remains challenging.
Cultural considerations and differential validity
Cultural sensitivity is essential in diagnosis and treatment planning.
Race, language, culture, spirituality, kinship, rituals, and healthcare access influence assessment and care.
Cultural considerations affect validity and perception of symptoms; clinicians must gather detailed histories and family views to tailor treatment.
Health system factors such as language barriers and insurance can affect access to care.
Prevalence, incidence, and comorbidity in populations
Prevalence: proportion of people in a defined population who have a condition at a specified time.
Example: in Australia, 2017–2018, 13.1\% of people experienced anxiety-related conditions; up from 10.6\% in 2014–2015.
Lifetime prevalence: proportion likely to experience symptoms of a disorder over a lifetime.
Example: lifetime prevalence of overall psychological disorders in Australia is around 45\%.
Incidence: frequency of new cases identified during a specified period.
Example: during 2020–2021, rac{1}{6} of people aged 16–85 experienced anxiety symptoms in that 12-month period, i.e., about 16.8\%, equating to roughly 3.3\text{ million} people.
Comorbidity: occurrence of more than one disorder at the same time; disorders often co-occur and cluster similarly to emotions.
Example: anxiety disorders commonly co-occur with Major Depressive Disorder due to overlapping emotional symptoms or underlying biological factors.
Summary: diagnosis framework and key concepts
Diagnostic approach combines:
Clinical interview to document symptoms and history.
DSM-5-TR criteria to classify disorders based on symptom patterns and impairment.
Psychometric assessments to quantify severity (e.g., BDI/BDI-II, EDI-3, SPAI).
Important concepts:
Syndrome definition and the role of clinically significant impairment.
Distinction between normal reactions to common stressors and disorders.
Role of collateral information and safety with patient confidentiality.
Pros and cons of classification (communication and research benefits vs risks of stigma and reliability concerns).
Dimensional versus categorical approaches to diagnosis.
Cultural sensitivity and the need for culturally valid assessment tools.
Epidemiological indicators: prevalence, incidence, and comorbidity help inform public health and research priorities.