Epidemiology and public mental health — service planning MEQ

(i) Measures. Incidence: new cases per population-time. Point prevalence: cases at one time point. Period prevalence: cases during an interval (e.g. 12 months). Lifetime prevalence: ever meeting criteria up to assessment (recall-sensitive). Current service need is best informed by period (especially 12-month) prevalence plus severity/disability and treatment coverage, not lifetime prevalence alone.^[3]

(ii) Admissions ≠ burden. Hospital rates reflect bed supply, thresholds for admission, community alternatives, legal pathways, and help-seeking — not community incidence. Selection enriches severity and comorbidity. Without a population denominator and survey sampling frame, rarity of admissions cannot prove rarity of disorder.^[8][3]

(iii) GBD language. Mental disorders generate large YLDs (non-fatal disability). YLLs from mental disorders as underlying cause are relatively lower than for many physical NCDs, but suicide and excess medical mortality are critical mortality pathways. DALYs = YLDs + YLLs support priority setting across diseases.^[1][2]

(iv) Prevention mix. Gordon: universal (school mental health curricula, social protection policies), selective (perinatal high-risk, unemployment/ACE-exposed families), indicated (subthreshold depression/anxiety; clinical high-risk psychosis pathways where appropriate).^[5] Rose: do not rely only on high-risk clinics — population strategies that shift mean risk (poverty reduction, alcohol policy, anti-bullying) prevent cases arising from the average-risk majority (prevention paradox).^[4] Finance officer's clinic-only plan is necessary but insufficient.

(v) Treatment gap and strategies. Treatment gap = proportion of people with mental disorders not receiving treatment.^[6] Strategies: (1) stepped care / primary care collaborative care for common disorders; (2) task-sharing and protocolised packages where specialist scarcity exists; (3) anti-stigma and access redesign plus rebalancing from inefficient hospital-only spend toward community coverage (scarcity–inequity–inefficiency triad).^[7][3]