Modelling mood disorders: An ACE solution?

Abstract

Objectives The treatment of mood disorders remains sub‐optimal. A major reason for this is our lack of understanding of the underlying pathophysiology of depression and bipolar disorder. A core problem is the lack of specificity of our current diagnoses. This paper discusses the history of this problem and posits a solution in the form of a more sophisticated model. Method The authors review the notable historical works that laid the foundations of mood disorder nosology; discuss the more recent influences that shaped modern diagnoses; and examine the evidence that mood disorders are characterised by multidimensional and longitudinal symptom profiles. Results The ACE model considers mood disorders as a combination of symptoms across three domains: Activity, Cognition, and Emotion; that vary over time. This multidimensional and longitudinal perspective is consistent with the prevalence of complex clinical presentations, such as mixed states, and highlights the importance of recurrence in mood disorders. Conclusions The ACE model encourages researchers to characterise patients from a number of equally important perspectives and, by doing so, add specificity to the treatment of mood disorders.

New windows on the treatment of bipolar disorder

“…For the purposes of defining mood disorders, we have in recent years proposed a new model that is still symptom based but shifts attention away from mood per se by incorporating additional domains—namely, activity (A) and cognition (C) alongside emotion (E)—which subsumes mood . This ACE Model is particularly important when considering the treatment of mania, which is more often signified by changes in activity and behaviour than its counterpart depression, along with significant cognitive changes that incorporate psychotic symptoms (see Figure ).…”

“…F I G U R E 1 ACE Model: (A) bipolar disorder, Schematic illustrates how the symptoms of both depression and mania comprise the domains of activity, cognition and emotion (ACE); (B) mania, More detailed schematic (close-up of mania) illustrates how the three symptom domains may vary individually in terms of severity during an episode of mania to produce a broad range of manic symptom patterns (for more detailed discussion see Gitlin & Malhi, 2020 5 ) attention away from mood per se by incorporating additional domains-namely, activity (A) and cognition (C) alongside emotion (E)-which subsumes mood. 3 This ACE Model is particularly important when considering the treatment of mania, which is more often signified by changes in activity and behaviour than its counterpart depression, along with significant cognitive changes that incorporate psychotic symptoms (see Figure 1).…”

Is RDoC our Doc? The clinical translation of scientific inquiry

“…4 Clinically, bipolar disorder is heralded by the occurrence of mania, which usually emerges from a pattern of recurrent depression with which it then intermingles throughout its course. 4 Clinically, bipolar disorder is heralded by the occurrence of mania, which usually emerges from a pattern of recurrent depression with which it then intermingles throughout its course.…”

“…In recent years, bipolar disorder has increasingly been conceptualised as a spectrum of disorders, consisting of symptoms that are themselves dimensional. 4 Clinically, bipolar disorder is heralded by the occurrence of mania, which usually emerges from a pattern of recurrent depression with which it then intermingles throughout its course. A difference in gender distribution and in responsivity to treatments separates bipolar disorder from major depression, but in practice, sufficient divergence of the two trajectories is only evident once manic F I G U R E 1 Schematic illustrating the units of analysis used by Research Domain Criteria (RDoC).…”

A useful model to improve understanding of mood disorder heterogeneity

“…Although other factors—such as economic hardship and epidemic opiate addiction—clearly contribute, most suicides are associated with a depressive mood disorder. Yet, as Malhi et al observe in their thoughtful review in this issue, only “modest” advances in our understanding has left diagnosis and treatment of mood disorders with shortcomings like delayed detection—particularly in bipolar disorder—and disappointing rates of response and remission. Life‐diminishing side effects such as sexual dysfunction and metabolic syndrome continue to weigh against the relief our medications give, and despite parity efforts, insurance coverage of psychotherapy remains poor.…”