The difference between melancholia and depression
<p><em><strong>Gordon Parker is an expert in mood disorders, founder of the Black Dog Institute and Scientia Professor at the University of New South Wales.</strong></em></p>
<p>First described by Hippocrates, “melancholia” or melancholic depression was considered a specific condition that commonly struck people out of the blue – and put them into the black. In modern times, it came to be described as “<span style="text-decoration: underline;"><strong><a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1979411/" target="_blank">endogenous depression</a></strong></span>” (coming from within) in contrast to depression stemming in response to external stressors.</p>
<p>In 1980, the third edition of the Diagnostic and Statistical Manual (<span style="text-decoration: underline;"><strong><a href="http://www.terapiacognitiva.eu/dwl/dsm5/DSM-III.pdf" target="_blank">DSM-III</a></strong></span>), the official classificatory system of the <span style="text-decoration: underline;"><strong><a href="http://www.psychiatry.org/" target="_blank">American Psychiatric Association</a></strong></span>, re-modelled depressive disorders. The new classification operated largely on degrees of severity, comprising “major” depression and several minor depressions.</p>
<p>This is how depression came to be modelled as a single entity, varying only by severity (this is known as the dimensional model). And over the last decade, this model has been extended to include “sub-clinical depressions”, which is basically when someone is sad or down but not diagnosable by formal mental illness criteria.</p>
<p><strong>Problematic model</strong></p>
<p><span style="text-decoration: underline;"><strong><a href="http://www.oup.com.au/titles/academic/psychology/9780199921577" target="_blank">The changes generated concern</a></strong></span> about the extension of “clinical depression” to include and “pathologise” sadness. While everyone feels down or sad sometimes, normally these moods pass, with little if any long-term consequences.</p>
<p>The boundary between this everyday kind of feeling down and clinical depression is imprecise. But the latter is associated with a greater severity of symptoms, such as losing sleep or thinking life isn’t worth living, lasts for longer and is much more likely to require treatment.</p>
<p>The dimensional model is intrinsically limited; “major depression” is no more informative a diagnosis than “major breathlessness”. It ignores the differing – biological, psychological and social – causes that may bring about a particular depressive condition and which inform the most appropriate therapeutic approach (be it an antidepressant drug, psychotherapy or social intervention).</p>
<p>Ignoring the cause of depression leads to both under-treatment, such as failure to prescribe an effective medication, and over-treatment, such as prescription of medication that’s unnecessary and may have side effects.</p>
<p>The model also essentially marginalised melancholia as a categorically different type of depression, with progressive DSM manuals according it insignificant status as a major depression “specifier” (an addendum to a diagnosis intended to provide more detail).</p>
<p>As a specifier, and not a disorder in its own right, melancholia is not considered categorically separate to other types of depression. And this matters – much less research and training is devoted to it as a result, and doctors are often unaware of its clinical implications.</p>
<p><strong>A distinct pattern</strong></p>
<p><span style="text-decoration: underline;"><strong><a href="http://www.blackdoginstitute.org.au/public/research/meetourresearchers/gordonparker.cfm" target="_blank">My research team</a></strong></span> is trying to establish melancholia’s categorical status and detection, and so improve its management. Here’s what we know – or think we know - about the distinctness of melancholia.</p>
<p>First, it shows a relatively clear pattern of <span style="text-decoration: underline;"><strong><a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3733615/" target="_blank">symptoms and signs</a></strong></span>. The individual experiences profound bleakness and has no desire to socialise, for instance, finding it hard to obtain any pleasure in life or to be cheered up.</p>
<p>Sufferers also experience a lack of energy and have difficulty concentrating, although they generally show “diurnal variation”, reporting improvement in mood and energy as the day goes on. Reflecting changes to their sleep/wake cycle, people with melancholia tend to wake early in the morning.</p>
<p>Episodes commonly emerge “out of the blue”. Even if it follows a stressor, it’s disproportionately more severe than might be expected and lasts longer than the stressor.</p>
<p>We’ve <span style="text-decoration: underline;"><strong><a href="http://www.ncbi.nlm.nih.gov/pubmed/22868058" target="_blank">progressively developed</a></strong></span> a clinician-rated measure (the SMPI or Sydney Melancholia Prototype Index) that has about 80% accuracy in differentiating melancholic and non-melancholic depression. When we add course of illness, causal and other clinical factors, we’ve been able to statistically <span style="text-decoration: underline;"><strong><a href="http://www.ncbi.nlm.nih.gov/pubmed/25565428" target="_blank">differentiate melancholic and non-melancholic depression</a></strong></span> at a high level.</p>
<p><strong>Physical underpinnings</strong></p>
<p>Melancholia has a strong genetic contribution, with sufferers likely to report a family history of “depression”, bipolar disorder or suicide. It’s largely biologically underpinned rather than caused by social factors (stressors) or psychological factors, such as personality style.</p>
<p>The illness is also unlikely to respond to placebo, whereas major depression has a <span style="text-decoration: underline;"><strong><a href="http://www.ncbi.nlm.nih.gov/pubmed/1388334" target="_blank">placebo response rate</a></strong></span> in excess of 40%. But melancholia shows greater response to physical treatments, such as antidepressant drugs (especially those that work on a broader number of neurotransmitters), and to ECT (electroconvulsive therapy). ECT is rarely required, however, if appropriate medications are prescribed.</p>
<p>Melancholia shows a lower response to psychotherapy, counselling and psychosocial interventions - these treatments are more salient and effective for non-melancholic depression.</p>
<p>It’s useful to draw an analogy here with diabetes: while Type 1 is more a biological disease state and generally requires drug treatment (insulin), Type II is more likely to reflect other factors, such as obesity. The latter generally benefits most from non-drug strategies, such as exercise and dietary changes.</p>
<p>Melancholia shows similar “treatment specificity”, with medication being the treatment of choice.</p>
<p><strong>Tracing biological origins</strong></p>
<p>Melancholia has long been thought to have <span style="text-decoration: underline;"><strong><a href="http://www.ncbi.nlm.nih.gov/pubmed/7458567" target="_blank">primary biological origins</a></strong></span>, including perturbations in the hypothalamic-pituitary-adrenal (HPA) axis, in sleep architecture and in neural circuits.</p>
<p>Early this year, our research team <span style="text-decoration: underline;"><strong><a href="http://www.ncbi.nlm.nih.gov/pubmed/1388334" target="_blank">published a neuroimaging study</a></strong></span> that suggested a differential key “signature” marker found only in people with melancholic depression (when compared to people with non-melancholic depression and non-depressed controls).</p>
<p>We showed incoming connections to the brain system that control attention (the insula) were halved, while connections from the insula to the brain’s executive control centre were also decreased.</p>
<p>The implications of these findings will require further investigation, but they could mean that a disruption to brain connectivity may explain some of melancholia’s symptoms.</p>
<p>Clearly, melancholia needs to be recognised as a distinct psychiatric condition – not simply as a more severe expression of depression. This recognition could lead to improved clinical and community awareness, which is important because managing melancholia requires a specific treatment approach.</p>
<p><em>Written by Gordon Parker. Republished with permission of <strong><a href="http://theconversation.com/" target="_blank"><span style="text-decoration: underline;">The Conversation</span>.</a></strong></em><img width="1" height="1" src="https://counter.theconversation.com/content/38025/count.gif?distributor=republish-lightbox-advanced" alt="The Conversation"/></p>
