Reference

Glossary

Key terms from our papers, in plain language. A living reference that grows with the papers.

Aetiological diagnosis: Diagnosing based on the underlying cause of a condition, rather than on its observable symptoms alone.
Anchoring: A cognitive bias where an initial piece of information (such as a first symptom) disproportionately shapes later judgments.
Behavioural inhibition: An early temperament marked by wariness toward unfamiliar people or situations, linked to later anxiety and introversion.
Bereavement exclusion: A former DSM-IV rule preventing a depression diagnosis shortly after a major loss. Its removal in DSM-5 was among the manual’s most contested changes.
Big Five Model: The dominant five-factor framework describing personality across openness, conscientiousness, extraversion, agreeableness, and neuroticism (OCEAN).
Comorbidity: The presence of two or more conditions in the same person — for example, the popularised “AuDHD” pairing of autism and ADHD.
Confirmation bias: The tendency to seek, weight, and recall evidence that supports an existing hypothesis while discounting evidence against it.
Constrained plasticity: This paper's conclusion that personality follows broad trajectories yet retains room to change within limits.
Deep brain stimulation (DBS): A treatment that uses targeted electrical stimulation of specific brain regions — explored for otherwise treatment-resistant depression.
Diathesis-Stress Model: The idea that a predisposition produces an outcome only when triggered by environmental stress.
DSM: The Diagnostic and Statistical Manual of Mental Disorders — the primary classification system used in Western psychiatry, published by the American Psychiatric Association.
Heritability: The share of variation in a trait across a population attributable to genetic differences; estimated at roughly 40–50% for personality.
Individualism vs. collectivism: A cultural dimension that shapes how traits like extraversion are valued and expressed.
Life-Course-Persistent vs. Adolescent-Limited: Moffitt's taxonomy contrasting antisocial behaviour that persists from childhood into adulthood with behaviour confined to the teenage years.
Longitudinal study: Research that follows the same individuals over a long period to track change.
Looping effect: Ian Hacking’s idea that naming a human category changes the people in it: as a label circulates, individuals shape their experience around it.
Monozygotic twins: Identical twins who share virtually all their genes; comparing them, especially when reared apart, helps estimate genetic influence.
Nature–nurture: The broader debate over how far biology versus environment shapes who we are.
Nomothetic: An approach that seeks general, law-like findings across many people, contrasted with idiographic study of the individual case.
Operant conditioning: Learning in which behaviour is shaped by its consequences, such as reinforcement (Skinner).
Over-diagnosis vs. better recognition: Two readings of rising diagnostic rates: either we are labelling normal variation as disorder, or we are finally identifying conditions previously missed.
Paradigm shift: Thomas Kuhn’s term for a fundamental change in the assumptions and methods of a field — here, shifts in how disorders are conceived.
Polygenic: Shaped by many genes of small individual effect rather than a single gene.
Rank-order stability: How well people keep their position on a trait relative to others over time; it tends to rise with age.
Reliability vs. validity: Reliability is whether a measure gives consistent results; validity is whether it actually captures the thing it claims to. A diagnosis can be reliable yet not valid.
Social Investment Theory: The view that taking on social roles such as work, marriage, or parenthood reshapes personality by rewarding certain behaviours.
Subgenual prefrontal cortex (sgPFC): A brain region involved in processing emotion, mood, and autonomic stress responses. Abnormal activity here is linked to major depressive disorder.
Symptom-based diagnosis: Classifying a disorder by the pattern of symptoms a person presents, as emphasised by the DSM-5. More reliable to apply, but its validity can be debated.