Marcelo Mendonca, MD – Brain Blogger Health and Science Blog Covering Brain Topics Wed, 30 May 2018 15:00:03 +0000 en-US hourly 1 Sad and in Pain – The Link Between Migraine and Depression Tue, 12 Jan 2016 16:00:04 +0000 Migraine is one of the most common painful disorders afflicting one in every eight people. It is characterized by throbbing and relatively unpredictable episodes of head pain that may last up to three days.

Various studies have shown that patients with migraine have a higher frequency of depression and anxiety: a finding that will be unsurprising to most people that deal with pain. We could try to explain this as the psychological reaction to the pain and its unpredictability. Nevertheless, the link is deeper than that.

In fact, in a population-based study that followed patients for two years, the risk of major depression was six times higher in patients with migraine but this risk was not significantly increased for other severe headaches – this is a strong argument against the “psychological” explanation. Additionally, the risk of having a migraine was up to three times higher in patients with a major depression, while the risk of having other non-migraine severe headache was not increased.

If these findings seem surprising, things can even get weirder. Migraine and depression independently share one unexpected environmental risk factors: childhood emotional abuse.

So are there common pathophysiological mechanisms for both disorders? For instance, serotonin seems to have a role both in depression and migraine. And could we learn something on migraine studying depression and learn something on depression studying migraine? This is when things get interesting.

A recent study evaluated the relationship between allodynia and depression in migraine. Allodynia is the sensation of pain when faced with stimuli that are usually non-painful (e.g., pain from the touch of the hairbrush when combing your hair). Allodynia is a clinical hallmark of a process known as central sensitization: Due to a frequent, often repetitive stimulation of pain-sensitive neurons they increase their response to sensory stimuli.

This study found that migraineurs with allodynia had a significantly higher level of depressive symptoms when compared with those without allodynia. This association was independently of the number of monthly headache episodes, gender or any other patient characteristics. Additionally, the severity of the depressive symptoms seems to be associated with the severity of allodynia.

These authors hypothesizes that allodynia could be a link between depression and migraine. A psychological explanation cannot be excluded at the moment (e.g., patients with more “pain” due to non-painful stimuli will be more depressed) but, we also know that depression and allodynia are, in the long term, factors associated with an increase of the frequency of migraine episodes linking them even more.

Further studies with a long-term follow-up of patients will be necessary to clarify this relationship. In addition, studies comparing the neurophysiologic characteristics of allodynic depressed migraineurs and allodynic non-depressed migraineurs (or other combinations) would help us to know if the mechanisms of allodynia are shared with those of depression. This could pave the way for new treatments for both depression and migraine.


Breslau N, Lipton RB, Stewart WF, Schultz LR, & Welch KM (2003). Comorbidity of migraine and depression: investigating potential etiology and prognosis. Neurology, 60 (8), 1308-12 PMID: 12707434

Goulart AC, Santos IS, Brunoni AR, Nunes MA, Passos VM, Griep RH, Lotufo PA, & Benseñor IM (2014). Migraine headaches and mood/anxiety disorders in the ELSA Brazil. Headache, 54 (8), 1310-9 PMID: 24898830

Mendonça MD, Caetano A, Viana-Baptista M, & CHLO Headache Study Group (2015). Association of depressive symptoms with allodynia in patients with migraine: A cross-sectional study. Cephalalgia : an international journal of headache PMID: 26634832

Tietjen GE, Buse DC, Fanning KM, Serrano D, Reed ML, & Lipton RB (2015). Recalled maltreatment, migraine, and tension-type headache: results of the AMPP study. Neurology, 84 (2), 132-40 PMID: 25540306

Image via Tiko Aramyan / Shutterstock.

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Personality Changes After Deep Brain Stimulation Thu, 29 Oct 2015 15:00:58 +0000 Deep Brain Stimulation (DBS) is a well-known and accepted treatment for neurological and psychiatric diseases. It consists of the implantation of electrodes into the brain, which send small electric impulses to specific neurons and pathways.

In Parkinson’s disease (PD), DBS clearly improves patients’ symptoms, functionality and quality of life in the long run. Nevertheless, it seems that the electrodes do not have motor-specific functions. DBS influences mental states and personality and in some cases it can even lead to a “new personality”.

One recent study showed that in 45 PD patients submitted to subthalamic nucleus DBS (one of the most common brain targets in PD) there was a personality change in the direction of increased impulsivity. Surprisingly, relatives were more sensitive to this alteration than patients themselves. The lower sensitivity of the patients to the mood and behavioral changes could be the reason for the complaint: “he/she is no longer the same”.

Yves Agid described that up to 65% of the married (or living with a partner) PD patients experienced a conjugal crisis after the operation. Different reasons could be found for this, but personality changes could clearly play a role.

Are we changing patients’ “identity” by using DBS? Probably yes: we are making them think differently, take risks in a different way and make decisions in a new manner.

But is it only the treatment that changes the patient? In all likelihood, no. The neurotransmitter dopamine – the loss of which is associated with the motor symptoms of PD – has a clear emotional and cognitive role. PD patients present dopamine deficit-related cognitive and emotional changes, that slowly progress at the rhythm of the neurodegeneration.

So, the acute personality change we impose with DBS in PD patients should always be measured against the cognitive and emotional disease-related changes that are biologically determined, and with the psychological changes induced by the diagnosis of a chronic neurodegenerative disease.

The clinical implications of these findings are that personality evaluation should be done both before and after DBS, and informant reports should be considered. Also, before surgery we need to discuss the personality changes risks with the patient and his family and try to manage expectations to minimize the common complaint: “Doctor, My husband is not the same!” and its impact in the familiar and environment.


Agid Y, Schüpbach M, Gargiulo M, Mallet L, Houeto JL, Behar C, Maltête D, Mesnage V, & Welter ML (2006). Neurosurgery in Parkinson’s disease: the doctor is happy, the patient less so? Journal of neural transmission. Supplementum (70), 409-14 PMID: 17017560

Frank MJ, Seeberger LC, & O’reilly RC (2004). By carrot or by stick: cognitive reinforcement learning in parkinsonism. Science (New York, N.Y.), 306 (5703), 1940-3 PMID: 15528409

Lewis CJ, Maier F, Horstkötter N, Zywczok A, Witt K, Eggers C, Meyer TD, Dembek TA, Maarouf M, Moro E, Zurowski M, Woopen C, Kuhn J, & Timmermann L (2015). Subjectively perceived personality and mood changes associated with subthalamic stimulation in patients with Parkinson’s disease. Psychological medicine, 45 (1), 73-85 PMID: 25066623

Pham U, Solbakk AK, Skogseid IM, Toft M, Pripp AH, Konglund AE, Andersson S, Haraldsen IR, Aarsland D, Dietrichs E, & Malt UF (2015). Personality changes after deep brain stimulation in Parkinson’s disease. Parkinson’s disease, 2015 PMID: 25705545

Witt K, Kuhn J, Timmermann L, Zurowski M, & Woopen C (2013). Deep Brain Stimulation and the Search for Identity. Neuroethics, 6, 499-511 PMID: 24273620

Image via Image Point Fr / Shutterstock.

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