04 - Impact of non adherence

Impact of non-adherence

928 The Maudsley® Prescribing Guidelines in Psychiatry CHAPTER 14 For chronic physical and mental disorders, the picture is not much better. Although 76% of patients with several conditions reported adhering to medication, electronic monitoring suggested that, in fact, only 44% did so.6 Consistent with previous findings, a 2020 meta-­analysis suggested that, overall, about 50% of people with mental health problems do not take their medication as prescribed.7 This, however, may be an oversimplification. It is probable that a small proportion of patients are fully adherent, the majority are partially adherent to varying degrees, and a few never take any medication at all (of their own volition).8 These findings are not only characteristic of western medical culture, they are reflected in other parts of the world.9 Adherence rates also vary both over time and across settings. For example, 10 days after discharge from hospital, up to 25% of patients with schizophrenia are partially or completely non-­adherent with oral treatment and this figure rises to 50% at 1 year and to 75% by 2 years.10 Other studies have reported 25.8% complete discontinuation of medication within 1 year of discharge from hospital.11 In some mental healthcare settings, the rate of non-­adherence may be as high as 90%.12 Diagnosis may also be significant. An Austrian study found that significantly more patients with schizophrenia (66%) did not take their medication as prescribed, compared with patients with affective disorders (47%) or those with other psychiatric diagnoses (41%).13 A major issue is that poor adherence almost always occurs without the knowledge of the prescriber. In one study, prescribers identified only half of those who were non-­ adherent.14 In another, 35% of patients referred for treatment of (apparently) refractory schizophrenia had sub-­therapeutic plasma concentrations and many of them had plasma levels of zero.15 Impact of non-­adherence Medicines are only effective if taken at a therapeutic dose. And they are effective. A 20-­ year follow-­up study of 62 250 patients with schizophrenia reported a significantly lower suicide mortality during antipsychotic use compared with non-­use.16 Antipsychotic use also decreased overall mortality. Poor adherence to medication is a major risk factor for worse outcomes including relapse in people with schizophrenia,17–19 bipolar disorder20 and depression.21 Wider health benefits are also lost. Depressed patients who do not take an antidepressant have a 20% increased risk of an incident myocardial infarction compared with those who do.22 The serious consequences of non-­adherence with medication may be mitigated by implementing routine monitoring. Data were collected as part of the National Confidential Inquiry into Suicide and Homicide by People with Mental Illness.23 This revealed that healthcare providers who had a policy regarding how to manage patients who are not taking their medication as prescribed had 20% fewer suicides than providers who did not have such a policy.23 Another reason that poorly adherent individuals do worse is that they may stop their medication abruptly and without monitoring (and without telling anyone). Abrupt cessation of almost all psychotropic drugs tends to worsen prognosis (see The Maudsley Deprescribing Guidelines). One of the findings that clearly illustrate the benefits of adherence is the example of depot antipsychotic medications. They do not differ pharmacologically from their oral equivalents but have consistently been shown to result in lower rates of readmission to