Major depressive disorder
Updates to Article Attributes
Major Depressive disorder (MDD) is the most common psychiatric disorder in both developed and developing countries. It is characterised by a persistently low mood and reduced interest in previously pleasurable activities.
Epidemiology
The 12 month prevalence of MDD in the general population is estimated at around 26%, while the lifetime prevalence is estimated at 24%. Patients with a family history of MDD, history of alcohol dependence, elderly patients (>65 years of age), lower education and unmarried patients tend to have higher rates of depression 1.
Clinical features
The Diagnostic and Statistical Manual (DSM-V) for mental health disorders recognises the following criteria for the diagnosis of MDD (must be present for at least 2 weeks)
- Low mood
- Decreased interest in pleasurable activities
- Poor sleep
- Poor appetite
- Decreased energy
- Difficulty in concentration
- Psychomotor retardation
- Thoughts of suicide
- Thoughts around guilt or hopelessness
These symptoms must not be attributable to an organic cause or substance use.
In the elderly, MDD can mimic early dementia as it often presents with reduced memory and psychomotor retardation.
In young children, angry outbursts and poor school performance may be the first signs of major depression 2.
Radiographic features
Although the diagnosis of MDD is made clinically, there are a number fo imaging findings observed on brain imaging.
CT and MRI
Imaging reveals lower thalamic volumes in patients presenting with a first episode MDD. This trend was consistent with patients presenting with multiple episodes. Younger patients tend to also have lower hippocampal volumes in conjunction with lower thalamic volumes. This is an important finding as it demonstrates the negative effect of high glucocorticoid concentrations (which are elevated in MDD) on the hippocampus.
However, it is important to note that studies have not been able to demonstrate any association between thalamic and hippocampal volumes and severity of MDD 3,4.
Some studies have shown an increase in the size of the amygdyla in patients with MDD. There appears to be a correlation between the size of the amygdyla and the severity of symptoms 5.
fMRI
Several studies have shown increased activity in the anterior cingulate cortex (ACC), which is predominantly implicated in allostasis. There appears to be reduced communication between the ACC and the amygdala, the pallidostriatum and the medial thalamus, suggesting a decreased regulatory effect of the ACC over the mood-regulating limbic areas.
There is a reduction in communication between the posterior cingulate cortex (PCC) and the caudate which could suggest abnormalities in the reward pathway 6.
Treatment and prognosis
The treatment of depression depends on the severity of the disease, but broadly involves the use of antidepressants, psychotherapy and electroconvulsive therapy for treatment refractory cases. Currently, imaging findings are not used to guide treatment.
Practice points
- Depression is the most common psychiatric disorder worldwide
- With the rise of individualised medicine, functional imaging of the brain will become important in the future for evaluating the severity of the disease and potential treatment options for patients.
-</ul><p>In the elderly, MDD can mimic early dementia as it often presents with reduced memory and psychomotor retardation. </p><p>In young children, angry outbursts and poor school performance may be the first signs of major depression <sup>2</sup>. </p><h4>Radiographic features</h4><p>Although the diagnosis of MDD is made clinically, there are a number fo imaging findings observed on brain imaging. </p><p> </p>- +</ul><p>These symptoms must not be attributable to an organic cause or substance use. </p><p>In the elderly, MDD can mimic early dementia as it often presents with reduced memory and psychomotor retardation. </p><p>In young children, angry outbursts and poor school performance may be the first signs of major depression <sup>2</sup>. </p><h4>Radiographic features</h4><p>Although the diagnosis of MDD is made clinically, there are a number fo imaging findings observed on brain imaging. </p><h5>CT and MRI</h5><p>Imaging reveals lower thalamic volumes in patients presenting with a first episode MDD. This trend was consistent with patients presenting with multiple episodes. Younger patients tend to also have lower <a title="Hippocampus" href="/articles/hippocampus">hippocampal</a> volumes in conjunction with lower <a title="Thalamus" href="/articles/thalamus">thalamic</a> volumes. This is an important finding as it demonstrates the negative effect of high glucocorticoid concentrations (which are elevated in MDD) on the hippocampus. </p><p>However, it is important to note that studies have not been able to demonstrate any association between thalamic and hippocampal volumes and severity of MDD <sup>3,4</sup>. </p><p>Some studies have shown an increase in the size of the amygdyla in patients with MDD. There appears to be a correlation between the size of the amygdyla and the severity of symptoms <sup>5</sup>. </p><h5>fMRI</h5><p>Several studies have shown increased activity in the <a title="anterior cingulate cortex" href="/articles/anterior-cingulate-cortex">anterior cingulate cortex</a> (ACC), which is predominantly implicated in allostasis. There appears to be reduced communication between the ACC and the <a title="Amygdala" href="/articles/amygdala">amygdala</a>, the <a title="pallidostriatum" href="/articles/pallidostriatum">pallidostriatum</a> and the <a title="Thalamus" href="/articles/thalamus">medial thalamus</a>, suggesting a decreased regulatory effect of the ACC over the mood-regulating <a title="Limbic system" href="/articles/limbic-system">limbic</a> areas. </p><p>There is a reduction in communication between the <a title="posterior cingulate cortex" href="/articles/posterior-cingulate-cortex">posterior cingulate cortex</a> (PCC) and the <a title="Caudate nucleus" href="/articles/caudate-nucleus">caudate</a> which could suggest abnormalities in the reward pathway <sup>6</sup>. </p><h4>Treatment and prognosis</h4><p>The treatment of depression depends on the severity of the disease, but broadly involves the use of antidepressants, psychotherapy and electroconvulsive therapy for treatment refractory cases. Currently, imaging findings are not used to guide treatment. </p><h4>Practice points</h4><ul>
- +<li>Depression is the most common psychiatric disorder worldwide</li>
- +<li>With the rise of individualised medicine, functional imaging of the brain will become important in the future for evaluating the severity of the disease and potential treatment options for patients. </li>
- +</ul><p> </p>
References changed:
- 1. Rubio, Jose M., Markowitz, John C., Alegría, Analucía, Pérez‐Fuentes, Gabriela, Liu, Shang‐Min, Lin, Keng‐Han, Blanco, Carlos. Epidemiology of chronic and nonchronic major depressive disorder: results from the national epidemiologic survey on alcohol and related conditions. (2011) Depression and Anxiety. 28 (8): 622. <a href="https://doi.org/10.1002/da.20864">doi:10.1002/da.20864</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/21796739">Pubmed</a> <span class="ref_v4"></span>
- 2. Carlson GA, Kashani JH. Phenomenology of major depression from childhood through adulthood: analysis of three studies. (1988) The American journal of psychiatry. 145 (10): 1222-5. <a href="https://doi.org/10.1176/ajp.145.10.1222">doi:10.1176/ajp.145.10.1222</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/3421342">Pubmed</a> <span class="ref_v4"></span>
- 3. Schmaal L, Veltman DJ, van Erp TG, Sämann PG, Frodl T, Jahanshad N, Loehrer E, Tiemeier H, Hofman A, Niessen WJ, Vernooij MW, Ikram MA, Wittfeld K, Grabe HJ, Block A, Hegenscheid K, Völzke H, Hoehn D, Czisch M, Lagopoulos J, Hatton SN, Hickie IB, Goya-Maldonado R, Krämer B, Gruber O, Couvy-Duchesne B, Rentería ME, Strike LT, Mills NT, de Zubicaray GI, McMahon KL, Medland SE, Martin NG, Gillespie NA, Wright MJ, Hall GB, MacQueen GM, Frey EM, Carballedo A, van Velzen LS, van Tol MJ, van der Wee NJ, Veer IM, Walter H, Schnell K, Schramm E, Normann C, Schoepf D, Konrad C, Zurowski B, Nickson T, McIntosh AM, Papmeyer M, Whalley HC, Sussmann JE, Godlewska BR, Cowen PJ, Fischer FH, Rose M, Penninx BW, Thompson PM, Hibar DP. Subcortical brain alterations in major depressive disorder: findings from the ENIGMA Major Depressive Disorder working group. (2016) Molecular psychiatry. 21 (6): 806-12. <a href="https://doi.org/10.1038/mp.2015.69">doi:10.1038/mp.2015.69</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26122586">Pubmed</a> <span class="ref_v4"></span>
- 4. Lui S, Zhou XJ, Sweeney JA, Gong Q. Psychoradiology: The Frontier of Neuroimaging in Psychiatry. (2016) Radiology. 281 (2): 357-372. <a href="https://doi.org/10.1148/radiol.2016152149">doi:10.1148/radiol.2016152149</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/27755933">Pubmed</a> <span class="ref_v4"></span>
- 5. van Eijndhoven P, van Wingen G, van Oijen K, Rijpkema M, Goraj B, Jan Verkes R, Oude Voshaar R, Fernández G, Buitelaar J, Tendolkar I. Amygdala volume marks the acute state in the early course of depression. (2009) Biological psychiatry. 65 (9): 812-8. <a href="https://doi.org/10.1016/j.biopsych.2008.10.027">doi:10.1016/j.biopsych.2008.10.027</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/19028381">Pubmed</a> <span class="ref_v4"></span>
- 6. Wang L, Hermens DF, Hickie IB, Lagopoulos J. A systematic review of resting-state functional-MRI studies in major depression. (2012) Journal of affective disorders. 142 (1-3): 6-12. <a href="https://doi.org/10.1016/j.jad.2012.04.013">doi:10.1016/j.jad.2012.04.013</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/22858266">Pubmed</a> <span class="ref_v4"></span>
Systems changed:
- Central Nervous System
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