Central Nervous System

Epilepsy

Epilepsy is a brain disease defined by any of the following conditions ¹:

• At least two spontaneous (i.e. unprovoked) or reflex epileptic seizures, occurring more than 24 hours apart;
• An unprovoked (or reflex) seizure and a probability of further seizures similar to the general risk of recurrence (at least 60%) after two spontaneous seizures over the next 10 years;
• Diagnosis of an epileptic syndrome.

An epileptic seizure is defined as “the presence of transient signs and/or symptoms resulting from synchronous and excessive neuronal activity”². Seizures are classified as having focal, generalized, or unknown onset (first level of diagnosis)³.

Regarding the type (second level of diagnosis), epilepsies can be classified as focal, generalized, focal and generalized together or unknown. As for the etiology of epilepsy, it can be structural, genetic, infectious, metabolic, immunological or unknown. The third level of diagnosis corresponds to the determination of the epileptic syndrome (a set of characteristics that tend to occur in association and that encompass the type of seizures, the electroencephalogram and imaging changes)³.

Epilepsy is considered resolved in individuals with age-dependent epileptic syndrome, having passed the age at which seizures usually occur in this syndrome; or patients who have remained seizure-free for at least 10 years, without antiepileptic medication in the last 5 years ¹.

In Portugal, it is estimated that epilepsy affects 4 to 7 per 1000 inhabitants, and the number of people who, although not epileptic, may have a seizure throughout their lives is estimated at around 1 in every 20⁴.

References:

1. Fisher RS, Acevedo C, Arzimanoglou A, et al. ILAE official report: a practical clinical definition of epilepsy. Epilepsia. 2014;55(4):475-482. doi:10.1111/epi.12550.
2. Fisher RS, Cross JH, French JA, et al. Operational classification of seizure types by the International League Against Epilepsy: Position Paper of the ILAE Commission for Classification and Terminology. Epilepsia. 2017;58(4):522-530. doi:10.1111/epi.13670.
3. Scheffer IE, Berkovic S, Capovilla G, et al. ILAE classification of the epilepsies: Position paper of the ILAE Commission for Classification and Terminology. Epilepsia. 2017;58(4):512-521. doi:10.1111/epi.13709.
4. Liga Portuguesa Contra a Epilepsia. Epilepsia e Generalidades. Disponível em: http://static.lvengine.net/epilepsia/Imgs/GENERALIDADES(1).pdf

 

Bipolar Disease

Bipolar disorder is characterized by the occurrence of manic or hypomanic episodes and the vast majority of individuals will also experience major depressive episodes during the course of their lives. Bipolar I disorder is characterized by the occurrence of full syndromatic manic episodes, whereas bipolar II disorder requires the lifetime experience of at least one major depressive episode (the amount of time that individuals with this condition spend in depression) and at least one hypomanic episode (a mild form of mania)¹.

Sometimes, manic and depressive characteristics may coexist in the same episode (or symptoms of opposite poles), defining these episodes as having mixed characteristics. When 4 or more mood episodes (of any polarity) occur within a period of 1 year, the specifier “with rapid cycles” is used¹.

Bipolar disorder affects approximately 1% of the population; in broader conceptualizations, including the so-called bipolar spectrum, the prevalence increases to at least 2.5% of the population, meaning that 1 in every 40 individuals in the world has symptoms compatible with bipolar2. In Portugal, the annual prevalence of bipolar disorder is estimated at 1.1% (of which 45.5% correspond to severe disorders, i.e., bipolar I disorder), while the lifetime prevalence is estimated at 2.6% of the population³.

Although the level of functioning may return to normal between episodes of bipolar I disorder, about 30% of patients experience severe work disability. In bipolar II disorder, at least 15% of patients maintain some level of dysfunction between episodes and 20% transition directly between episodes without recovering between them. In both types of bipolar disorder, functional and occupational recovery often falls far short of symptomatic recovery. Additionally, cognitive deficits are often present that can persist even during periods of euthymic mood.¹.

 References:

1. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, VA: American Psychiatric Association, 2013.
2. Malhi GS, Bell E, Boyce P, et al. The 2020 Royal Australian and New Zealand College of psychiatrists clinical practice guidelines for mood disorders: Bipolar disorder summary. Bipolar Disord. 2020;22(8):805-821. doi:10.1111/bdi.13036.
3. Caldas de Almeida JM, Xavier M. Estudo Epidemiológico Nacional de Saúde Mental. Disponível em: http://www.fcm.unl.pt/main/alldoc/galeria_imagens/Relatorio_Estudo_Saude-Mental_2.pdf

 

Depression

Depressive disorders include a set of clinical conditions that have as a common characteristic the presence of sadness, emptiness or irritable mood, accompanied by somatic and cognitive changes that significantly affect the individual’s ability to function¹.

Major depressive disorder is characterized by the occurrence of distinct depressive episodes, lasting at least 2 weeks (although the duration is often considerably longer), involving affective, cognitive and neurovegetative symptoms. In most cases, major depressive disorder is a recurrent condition¹.

Globally, the annual prevalence of major depression is 6%, with a lifetime prevalence of 11.1% to 14.6%. In Portugal, the annual and lifetime prevalence of major depression are 6.8% and 16.7%, respectively³.

The impact on the functioning of depression varies depending on its individual symptoms and can, in some cases, lead to complete functional incapacity, including the impossibility of carrying out basic self-care needs. In a general medical context, the presence of major depression is associated with more painful complaints and physical illnesses and a greater decrease in physical and social functioning¹.

Insomnia is often the presenting complaint of major depression1. Insomnia is present in 67% to 84% of adults with depression and more severe symptoms of insomnia are associated with greater functional disability and greater severity of depression symptoms. Insomnia symptoms frequently persist, occurring in 94.6% of patients in incomplete remission and even in 72% of those in complete remission after antidepressant treatment⁴.

References:

1. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, VA: American Psychiatric Association, 2013.
2. Malhi GS, Bell E, Singh AB, et al. The 2020 Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for mood disorders: Major depression summary. Bipolar Disord. 2020;22(8):788-804. doi:10.1111/bdi.13035.
3. Caldas de Almeida JM, Xavier M. Estudo Epidemiológico Nacional de Saúde Mental. Disponível em: http://www.fcm.unl.pt/main/alldoc/galeria_imagens/Relatorio_Estudo_Saude-Mental_2.pdf
4. Asarnow LD, Manber R. Cognitive Behavioral Therapy for Insomnia in Depression. Sleep Med Clin. 2019;14(2):177-184. doi:10.1016/j.jsmc.2019.01.009.