Treatment adherence in psychosis From Bandolier, Dec 2003

This Bandolier article, published in the journal in Dec 2003, focuses on one review,¹ which found that one patient in four with a psychiatric diagnosis is noncompliant with medications.

To a large extent, in fact, the Bandolier article focuses on the methodology of the review and the studies it encompasses.

Pertinent Points

• Studies, all of which dealt with adherence of patients with a severe mental disorder, covered by the review dated from 1980, but the date of the last search was not given. For the purposes of the review, non-adherence was defined as either not taking drugs as prescribed or not keeping appointments as scheduled. Significantly, however, any method of specifying adherence Vs non-adherence was allowed.
• Of the 103 studies (24,000 patients), half had fewer than 100 patients; the majority of patients (84%) were in studies with more than 150 subjects. This becomes important because trial size turns out to be a major factor in calculating the rates of non-adherence. (The overall weighted mean rate of non-adherence was 26%, where weighting was by size of study. The unweighted average was 38%.), with much lower rates of non-adherence in the bulk of patients in studies with more than 151 patients, whether or not weighting was used.

Findings

As the Bandolier authors note,

The knowledge, as already noted, is that about one in four patients with severe mental illness is non-adherent, regardless of specific psychiatric diagnosis.

The methodological insight is that that trial size may be even more important than previously assumed, that rather than being the difference between a good study and a better study, size may be the difference between accurate and misleading results. That small studies produced much higher non-adherence rates. The authors point out that this may indicate that small studies could have other problems that make them less reliable.

Footnote

1. M Nosé et al. How often do patients with psychosis fail to adhere to treatment programmes? A systematic review. Psychological Medicine 2003 33: 1149-1160. [back]

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