3.1 Mixed anxiety and depressive disorder – a separate diagnostic category?
Mixed anxiety and depressive disorder, or ‘MADD’, is included as a separate diagnostic category in ICD-10, but has not been included in DSM-5. MADD is characterised in ICD-10 by subsyndromal symptoms of anxiety and depression (i.e symptoms that are severe enough to justify the diagnosis of MADD, but neither of which predominate sufficiently to warrant a separate diagnosis of an anxiety disorder or major depression). The validity and clinical usefulness of MADD as a diagnostic category continue to be debated and disputed, due to 'divergent results regarding its prevalence and course, diagnostic stability over time, and nosological inconsistencies between subthreshold and threshold presentations of anxiety and depressive disorders' (Möller et al., 2016). ICD-11 continues to include a separate diagnostic category, however subsyndromal, comorbid anxiety, and depression has been moved from the anxiety disorders to the depressive disorders section and renamed 'mixed depressive and anxiety disorder' (ICD-11, 2019). This change seems to align to some extent with the update to the DSM − although DSM-5 does not include a diagnostic category for MADD, 'the specifier "with anxious distress" has been added to depressive and bipolar disorders, and thus patients presenting with co-morbid, subsyndromal, equally important anxiety and depressive symptoms may be coded to be suffering from "Other specified depressive disorder with anxious distress”' (Möller et al., 2016).
Patients who meet ICD-10 diagnostic criteria for MADD frequently present in primary care settings, and many present initially with somatic complaints (e.g. muscle tension, headaches, palpitations, tachycardia, shortness of breath, etc.) that can ‘mask’ an underlying affective (mood) disorder. Patients with cardiovascular disease, cancer, diabetes and other metabolic conditions may also have comorbid symptoms of anxiety and/or depression. Möller et al. (2016) argue that a diagnosis of MADD 'may enable patients to gain access to appropriate treatments early', will help to alleviate distress, prevent worsening of symptoms (i.e. developing into a more serious illness), and reduce the overall socioeconomic costs associated with the illness. But would the inclusion of MADD within a separate classification system not lead to ‘medicalisation’ and further stigmatisation?
The authors explain: 'We are not advocating to lower the bar for a diagnosis and thus to unnecessarily tag millions of moderately "neurotic" individuals with a psychiatric label. Our concern is with patients who suffer profoundly from distress… denying such patients an appropriate diagnosis could well imply to withhold [sic] the required treatment as well.' (p. 732)
Möller and colleagues (2016) make an intriguing analogy with treatment for the common cold, stating that 'in day-to-day clinical practice, particularly in primary care, physicians diagnose and treat large numbers of patients who present with comparatively trivial, self-limiting disorders'.
A good example is the common cold which although it [sic] usually subsides within two weeks untreated, may cause profound, subjective suffering and has an enormous economic impact, mainly through loss of productivity. Of course, treatment of the common cold appears to be perfectly justified both from a clinical and from an economic perspective, since (a) patients suffer, (b) there is a certain risk of much more severe and difficult to treat complications and exacerbations, and (c) secondary costs, resulting from disability, may be reduced by an acceleration of recovery. (p. 733)
They argue that 'We have never heard of any criticism of common cold treatment founded in the conviction that a diagnosis of the disorder could lead to unjustified medicalization and stigmatization of millions of individuals who suffer from minor, self-limiting symptoms'. They further explain that 'This is because somatic disorders still appear to be perceived as something more "acceptable" and less stigmatizing than psychiatric disorders, both in the general population and in the medical community. One thing that somatic and psychiatric disorders have in common is that patients suffer' (Möller et al. 2016).