Bipolar Neuroscience

Bipolar Disorder (BD) affects 2% of the world population, giving rise to a suicide rate of 20 times that of the general population. Although BD has been studied extensively, some elements of this disorder have been largely neglected. Bipolar Disorder comprises 4 main subtypes of Bipolar I, Bipolar II, Cyclothymia, and Biplar NOS (not otherwise specified). Bipolar Disorder is a mood disorder in which individuals experience episodes of mania, hypomania, hyperthymia, depression, and mixed episodes[1]. Full recovery is often not possible for individuals while cycling between episodes, which makes it a major cause of disability. One area of research involves looking into altering neurotransmitter function to understand the causes of BD[2]. Family and twin-studies point to genetic causes of BD, where mitochondrial inheritance is a factor in inheritance[2]. Brain region changes are profound in these individuals, including volume changes in the lateral ventricles and globus pallidus, as well as abnormalities in regions such as the amygdala. Cyclothymia is considered to be a ‘subthreshold’ type of BD characterized by oscillating episodes of hypomanic and depressive states with abrupt transitions. Consequently, many do not recognize cyclothymia as a distinct disorder, but rather as a temperament trait or a co-morbid characteristic, despite its classification in the DSM-IV since 1980. BD relates to sleep pattern irregularities and has the greatest abnormalities during the euthymic phase (or inter-phase episode) of BD. Sleep patterns are similar to insomniacs and are marked by deficiencies in the continuity of sleep.

Bibliography
1. Smith, D.J., Whitham, E.A., Ghaemi, S.N. Bipolar Disoder. Handbook of Clinical Neurology (2012)106:251-63.
2. Müller-Oerlinghausen, B., Berghöfer, A., Bauer, M. Bipolar Disoder. The Lancet (2002)359:241-47.


Cyclothymia

main article: Cyclothymia
author: Zahra Maamir

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retrieved from eHow.com

Bipolar Disorder background
Bipolar Disorder (BD) is a mood disorder in which individuals experience varying episodes of mania, hypomania, hyperthymia and depression [1]. The four classified subtypes of BD are bipolar I and II, Cyclothymia and bipolar NOS (Not Otherwise Specified). BD has been studied extensively, especially bipolar I and II, however the other subtypes have been left in the grey area. Although bipolar I and II dominate in the literature, it has recently been shown that the four BD subtypes have comparable prevalence rates [2]. In total, BD affects 1-2% of the population, however more recent findings suggest prevalence rates as high as 5-10% [3][4].

Cyclothymia background
Cyclothymia, also known as Cyclothymic disorder or Cyclothymic temperament, is considered to be a ‘sub-threshold’ type of BD characterized by oscillating episodes of hypomanic and depressive episodes, usually transitioning abruptly [5]. Many do not recognize Cyclothymia as a distinct disorder, but rather as a temperament trait or a co-morbid characteristic, despite its classification in the DSM-IV since 1980 [6][7][8]. This disagreement in the literature is impeding our understanding of Cyclothymia and this neglect needs to be revised. Currently, a circadian component to Cyclothymia is being investigated.

Bipolar Disorder Subtypes
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Differentiating between the different subtypes of BD:
Bipolar I involves episodes of mania and depression.
Bipolar II involves episodes of hypomania and depression.
Cyclothymia involves oscillating episodes of hypomania and a state nearing depression
Bibliography
1. Smith, D.J., Whitham, E.A., Ghaemi, S.N. (2012). Bipolar Disorder. Handbook of Clinical Neurology. 106:251-63.
2. Merikangas, K.R., Akiskal, H.S., Angst J. (2007). Lifetime and 12 month prevalence of bipolar spectrum disorder in the National Comorbidity Survey Replication. Arch Gen Psychiatry. 64:543–552.
3. Malhi, G.S., Chengappa, K.N., Gershon, S., Goldberg, J.F. (2010). Hypomania: hype or mania? Bipolar Disorder. 12:758-63.
4. Judd, L.J., Akiskal, H.S. (2003). The prevalence and disability of bipolar spectrum disorders in the US population: re-analysis of the ECA database taking into account subthreshold cases. Journal of Affective Disorders. 73:123–131.
5. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders: DSM-IV-TR. Washington DC: American Psychiatric Association; 1994
6. Parker, G., McCraw, S., Fletcher, K. (2012). Cyclothymia. Depress Anxiety. 29(6):487-94.
7. Akiskal, H.S. (1981). Subaffective disorders: dysthymic, cyclothymic and bipolar II disorders in the borderline realm. Psychiatr. Clin. North Am. 4(1):25-46.
8. Akiskal, H., Khani, M., Scott-Strauss, A. (1979). Cyclothymic temperamental disorders. The Psychiatric Clinics of North America. 2:527–554.
9. Whalley, H.C., Sussmann, J.E., Chakirova, G., Mukerjee, P., Peel, A., McKirdy, J., Hall, J., Johnstone, E.C., Lawrie, S.M., McIntosh, A.M. (2011). The neural basis of familial risk and temperamental variation in individuals at high risk of bipolar disorder. Biol Psychiatry. 70(4):343-9.


Sleep Irregularities in Bipolar Disorder

main article: Sleep Irregularities in Bipolar Disorder
author: Aalia Shabbar

Phases of Bipolar Disorder
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Retrieved from: clevelandclinicmeded.com

Bipolar Disorder (BD) Background

Bipolar Disorder (BD) affects 2% of the world population, giving rise to a suicide rate of 20 times that of the general population. BD is a mood disorder in which individuals experience episodes of mania, hypomania, hyperthymia, depression, and mixed episodes[1]. A symptom that is found to recur after manic or depressive episodes is sleep disturbance. Particularly, during the inter-episode period, where no symptomologies are present, irregularities in sleep patterns are evident[2]. Individuals are reported to have longer sleep times, less efficient sleep, and more variation in sleep with constant periods of wakening[2]. A recent study reported that the sleep of individuals diagnosed with BD is similar to that of insomniacs. Insomniacs tend to overestimate the amount of time it takes them to fall asleep, as well as underestimate their total sleep time, which is a characteristic similar to what individuals with BD would report[3].

Bipolar Disorder
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Bibliography
1. Smith, D.J., Whitham, E.A., Ghaemi, S.N. Bipolar Disoder. Handbook of Clinical Neurology (2012)106:251-63.
2. Sylvia, L.G. et al. Sleep disturbance in euthymic bipolar patients. Journal of Psychopharmacology (2012)26(8):1108-12.
3. Harvey, A.G. et al. Sleep-related functioning in euthymic patients with bipolar disorder, patients with insomnia, and subjects without sleep problems. Am J Psychiatry (2005)162:50-57.



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