In the U.K. people with mental-health problems who are very ill are referred by community mental-health services to crisis-resolution home treatment (CRHT) services which decide whether to treat them themselves or to refer them on to hospital. Both these things are very expensive so anything which cuts down on their use could potentially save a lot of money. Researchers from Northumberland Tyne and Wear NHS Trust and Newcastle University looked into the impact of non-adherence (people not taking their drugs properly) on referral to CRHTs. They found that 30% of people referred to CRHTs had not been taking their medication properly in the month beforehand. These people were three times as likely to have a drug problem as well as a mental-health one and were two-and-a-half times as likely to be admitted to a psychiatric hospital.
Sreenath, San ... [et al] - Medication adherence in crisis? Journal of Mental Health, October 2010; 19(5): 470–474