Bipolar Disorder vs. Epilepsy

How are they connected?

 Epilepsy is a condition in the brain that causes seizures or brain dysfunction due to excessive neuron discharge. Psychiatric disturbances are common in epilepsy.

 Mood disorder’s are often comorbid with epilepsy, these two conditions share many biochemical and pathophysiological underpinnings, such as kindling, change in neurotransmitters, and modifications in messenger systems1. Both are episodic conditions that can worsen over time (kindling) and become chronic. Mood instability is frequent in those with epilepsy, but they don’t always meet the criteria for an actual affective (mood) disorder. There is a link between neurobehavioural disorders and temporal lobe epilepsy, as well as a strong link with complex partial epilepsy2.

I’m not going to get into excessive definitions of epilepsy, as this is a bipolar blog, but I will try to be as descriptive as possible.

 One problem with the consensus that epilepsy is comorbid with mood disorders is that the sampling could be incorrect because of inadequate control groups. But for the most part, professionals believe the link between mood disorders and epilepsy is quite strong, though a few disagree.

In studying the relationship between epilepsy and psychiatric disorders, care must be taken to differentiate between the following:

  • Psychiatric disorders caused by the seizures of the epilepsy – Ictal disorders, postictal disorders, and interictal disorders
  • Epileptic and psychiatric disorders caused by common brain pathology
  • Epileptic and psychiatric disorders that happen to coexist in the same patient but are not causally related

Factors in the relationship between epilepsy and behavioural & mood disorders

Epilepsy and mood disorders share a neuropathology3 , genetic predisposition and developmental disturbances. There can be problems with hormones and alteration of receptor sensitivity (receptors not working the way they should). Both could be caused by complications of medical or surgical treatment., and consequence of psychosocial burden of epilepsy itself2.

 

Because of the phenomenology of epilepsy, the close association between epilepsy and psychiatry has a long history. The traditional approach to epilepsy care has been to focus on the seizures and their treatment. Concentrating only on the treatment of the seizures, which occupy only a small proportion of the patient’s life, does not seem to address many of the issues that have an adverse impact on the quality of life of the patient with epilepsy.”

Statistics

20-30% of those with epilepsy have psychiatric disturbances of some kind. Tucker reports that 70% of those with complex partial epilepsy met criteria for at least one disorder in the DSM. 58% of those patients suffered from depression, 32% had an anxiety disorder and 13% had psychosis. The most common conditions in epilepsy are depression, anxiety and psychosis.

There is a risk of psychosis in epilepsy 6-12x’s that of the general population.

Psychiatric Disorder

Controls

Patients With Epilepsy

Major depressive disorder

10.7%

17.4%

Anxiety disorder

11.2%

22.8%

Mood/anxiety disorder

19.6%

34.2%

Suicidal Ideation

13.3%

25.0%

Others

20.7%

35.5%

 

A number of studies have demonstrated that affective disorders in epilepsy represent a common psychiatric comorbidity; however, most of the classic neuropsychiatric literature focuses on depression, which is actually prominent, but little is known about bipolar depression, and very little about mania, in epilepsy4

 

The Frontal Lobe

According to NAMI, bipolar disorder is caused by a chemical imbalance in the frontal lobe of the brain. In a manic state, activity in the frontal lobe increases signifigantly5. With depression, activity in the frontal lobe decreases. MRI’s show that there are small inconsistencies in the white matter of the brain, caused by loss of myelin.

 

Frontal lobe epilepsy is the second most common type of epilepsy, with temporal lobe epilepsy being the first6. It is often genetic. The frontal lobes are large areas that control a good portion of the brain and body, so when a seizure begins in the frontal lobes, it goes haywire and spreads to other parts of the brain causing a tonic-clonic (lying on the ground jerking around) seizure.

 

How does that relate them?

Because the same area of the brain is affected, mood stabilizers (except for lithium) called anti-consultants can work on someone with bipolar disorder and someone with epilepsy. There is little known on exactly why this happens. The two conditions can be considered comorbid because the same medications can be used to treat them. (And many with epilepsy are also mentally ill)

 

Medications

The class of medications, anti-consultants, target the same area of the brain for epilepsy and bipolar disorder. The medications target the GABA and glutamate neurotransmitters. Glutamate in high amounts is associated with bipolar disorder mania and epilepsy. This relates them because the same neurotransmitters are targeted and dysfunctional7. Bipolar disorder and epilepsy can also occur after a head injury. Estrogen also makes bipolar disorder and epilepsy worse.

 

Conclusion

So there you have it, links between epilepsy and bipolar disorder. There still needs to be a lot of research done, but evidence is pointing that the two may be comorbid (existing together) conditions.

 

 

  1. http://www.ncbi.nlm.nih.gov/pubmed/20021317

  2. http://emedicine.medscape.com/article/1186336-overview

  3. A deviation from the norm in the nervous system

  4. http://nro.sagepub.com/content/13/4/392.abstract

  5. http://www.ehow.com/facts_4813697_frontal-lobe-effects-bipolar-disorder.html

  6. http://www.epilepsy.com/epilepsy/epilepsy_frontallobe

  7. http://www.bipolarworld.net/Phelps/ph_2000/ph8.htm

     

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