It has been estimated that out of the 750 million prescriptions written each year in the US and England , there are over 520 million cases of partial or total non-adherence expected in a single year. Annually, 230-250 million prescribed medications will not be taken and a similar number will not follow completely the regimen prescribed by their doctor (Buckalew & Sallis, 1986)

Of all patients, 30-40% fail to follow preventative regimens and 20-30% fail to follow curative (relief of symptoms) medication regimes. Moreover, when long-term medication is prescribed, 50% fail to adhere (Haynes et al., 1979).

Of adolescent cancer patients, 40-60% fail to take prescribed medications as directed (Smith, Rosen, & Trueworthy, 1979; Tebbi et al., 1986)

Only 7% of diabetic patients adhere to all steps considered necessary for good control (Cerkoney & Hart, 1980).

In pediatric populations nonadherence by parents to medication regimens prescribed for their children is 50%, with a range from 34-82% (Olson et al., 1985).

Among parents of hyperactive children only about one-fourth adhere to prescribe medication (Brown, Borden, & Clingerman, 1985).

In the treatment of addictive behaviors such as smoking, heroin, and alcohol, 60% of those successfully treated revert to their prior behavior patterns within 3 months after therapy, increasing to 70% at 6 months and 75% at 12 months (Hunt & Bespalec, 1974). Relapse rates for addictions are in the range of 50-90%, with relapse rates for various addictions stabilizing within the first three months (Brownell et al., 1986).

One-third or more of the individuals coming to a clinic and judged to be in need of psychotherapy refused the treatment after it was offered to them (Garfield, 1980). Of patients initially referred for outpatient group therapy, 41% never attended a session and of those who attended 25-57% dropped out prematurely ( Klein & Carroll, 1986).