Fig. 4

Simplified schema of hypothetical clinic caseload in the first 10 years of ADHD service delivery with no limit to growth in provision of funding or staff resources. With reference to year 1 at 100%, and assuming the following rates of medication discontinuation: 25% decrease in medication one year after diagnosis and a 10% yearly drop after this [110], and that ADHD patients are only seen in secondary services for routine follow-up in the first year after medication discontinuation. A clinic caseload in the context of stable referral rates, B clinic caseload in the context of a 5% yearly increase in referral/diagnosis/treatment rates. There will be other complicating factors beyond the scope of this model, such as migration in/out of catchment, increasing awareness in population over time, potential for diagnostic thresholds to change with revisions to diagnostic criteria