Plain-language explanation.
Personality psychology studies stable patterns of thoughts, feelings, and behaviours that distinguish individuals, bridging basic science and clinical application.
Core concepts and standard treatment.
Core personality psychology covers trait approaches (Allport — idiographic vs nomothetic; Cattell 16PF; Eysenck PEN model — psychoticism, extraversion, neuroticism — arousal theory; Big Five — OCEAN — McCrae and Costa — NEO PI-R — cross-cultural replication; HEXACO adds Honesty-Humility; behavioural genetics — twin studies — heritability ~50% — Bouchard Minnesota), personality assessment (MMPI-3; NEO PI-R; MBTI — psychometric critique — test-retest instability; Hogan HPI; Rorschach reliability concerns; TAT), and psychoanalytic approaches (Freud — id, ego, superego; defence mechanisms — repression, denial, projection, sublimation; psychosexual stages; Jung — archetypes — shadow — collective unconscious; Winnicott — transitional object; object relations; Bowlby attachment as personality influence).
Deeper theory, debates and edge cases.
Advanced personality psychology covers personality disorders (DSM-5 cluster A paranoid, schizoid, schizotypal; cluster B antisocial, borderline, histrionic, narcissistic; cluster C avoidant, dependent, OCD; ICD-11 dimensional model — severity plus trait domains; BPD — McLean Study; PCL-R — Hare psychopathy checklist; schema therapy for PD — Young), personality across the lifespan (Roberts meta-analysis — maturity principle — conscientiousness and agreeableness increase with age; Markus and Kitayama — independent vs interdependent self-construal; cross-cultural personality — Church), and applied personality (conscientiousness and longevity — Friedman; Type A and cardiovascular risk; Schmidt and Hunter meta-analysis — predictive validity of conscientiousness in selection; dark triad in workplace — counterproductive work behaviour).
How it is applied in practice.
At the occupational psychologist level, practitioners contribute to Journal of Personality; advise on selection assessment (SHL OPQ32; Hogan HPI, HDS, MVPI derailers; assessment centre design; SJT situational judgement tests; Equality Act adverse impact — four-fifths rule); conduct clinical personality assessment (MCMI-IV; PAI; HCR-20 violence risk; PCL-R forensic; MHA Mental Health Act assessment); design development interventions (executive coaching — Hogan derailer awareness; DBT for BPD; ACT self-concept; narrative identity — McAdams redemptive self); and contribute to personality neuroscience (dopamine and extraversion; serotonin and neuroticism; prefrontal cortex and conscientiousness — DeYoung neuroimaging).