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Mental Health Service Demand Calculator

Work out mental health service demand instantly with clear inputs, formula shown and shareable results.

About Mental Health Service Demand Calculator

Applies prevalence to the population, removes those already treated and converts unmet need into sessions and therapist numbers.

Formula

Service demand

People affected = population x prevalence; unreached = affected x treatment gap; sessions = unreached x sessions per patient; therapists = sessions / (20 sessions a week x 45 working weeks)

Worked example

With the default values below, Mental Health Service Demand Calculator returns People not currently reached of 45,000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Population servedaccepts 1–100,000,000
500,000
Prevalence of common mental disordersaccepts 1–50
15
Share not currently reachedaccepts 0–99
60
Sessions per treated patientaccepts 1–40
8

Results

People not currently reached
45,000
People affected
75,000
Therapy sessions required
360,000
Therapists required at 20 sessions a week
400.0

Step by step

  1. 1Values used
  2. 2Service demand
  3. 3People not currently reached= 45,000
  4. 4People affected= 75,000
  5. 5Therapy sessions required= 360,000
  6. 6Therapists required at 20 sessions a week= 400.0

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What is the treatment gap?

The share of people with a diagnosable disorder who receive no treatment, exceeding 70% in many low-income settings.

Does everyone need therapy?

No. Stepped care means many people are managed with brief interventions or guided self-help rather than full courses.

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