Showing posts with label Seasonality effect. Show all posts
Showing posts with label Seasonality effect. Show all posts

Tuesday, 24 January 2023

ICD-11 Criteria For Seasonal Pattern Of Mood Episode Onset

Foundation URI : http://id.who.int/icd/entity/822487798

ICD-11 Criteria For Seasonal Pattern Of Mood Episode Onset

6A80.4 

Description

In the context of recurrent depressive disorder, bipolar type I or bipolar type II disorder, there has been a regular seasonal pattern of onset and remission of at least one type of episode (i.e., depressive, manic, mixed, or hypomanic episodes), with a substantial majority of the relevant mood episodes corresponding to the seasonal pattern. (In bipolar type I and bipolar type II disorder, all types of mood episodes may not follow this pattern.) A seasonal pattern should be differentiated from an episode that is coincidental with a particular season but predominantly related to a psychological stressor that regularly occurs at that time of the year (e.g., seasonal unemployment).

Diagnostic Requirements

This specifier can be applied if:

  • In the context of Bipolar Type I or Bipolar Type II Disorder there has been a regular seasonal pattern of onset and remission of at least one type of episode (i.e., Depressive, Manic, Mixed, or Hypomanic Episodes); the other types of Mood Episodes may not follow this pattern; or
  • In the context of Recurrent Depressive Disorder there has been a regular seasonal pattern of onset and remission of Depressive Episodes.
  • A substantial majority of the relevant Mood Episodes should correspond with the seasonal pattern.
  • A seasonal pattern should be differentiated from an episode that is coincidental with a particular season but predominantly related to a psychological stressor that regularly occurs at that time of the year (e.g., seasonal unemployment).

Reference:

International Classification of Diseases Eleventh Revision (ICD-11). Geneva: World Health Organization; 2022. License: CC BY-ND 3.0 IGO.
https://creativecommons.org/licenses/by-nc-nd/3.0/igo/

Thursday, 12 May 2022

Seasonality Effect

Seasonality Effect

The seasonality effect in schizophrenia refers to the observation that the symptoms of schizophrenia appear to follow a seasonal pattern, with an increased incidence of relapse or exacerbation of symptoms during specific times of the year, such as winter. One study that investigated the seasonality effect in schizophrenia found that hospital admission rates for patients with schizophrenia were highest in the winter months and lowest in the summer months (Weiser et al., 2005). Another study found similar results, with a higher frequency of psychosis relapses in winter compared to summer months (Kilbane et al., 1996). Additionally, research has suggested that low levels of sunlight, which is more common in winter months, may play a role in the seasonal variation of symptoms in schizophrenia. For example, a study showed that exposure to bright light therapy was associated with a decrease in the severity of symptoms in patients with schizophrenia (Levine et al., 1998). In conclusion, the seasonality effect in schizophrenia is a well-documented phenomenon. Several studies have found a correlation between the severity of symptoms and the time of year, with winter months showing a higher incidence of relapse or exacerbation of symptoms. Further research is needed to fully understand this effect's underlying mechanisms and develop appropriate interventions to mitigate its impact on patients with schizophrenia.

References:

  1. Kilbane, M., Sredl, D., & Leahy, L. (1996). Seasonality in relapse of schizophrenia. The Journal of Nervous and Mental Disease, 184(12), 755-758.
  2. Levine, J., Stevens, R. J., Rousseau, M. U., & Taillard, J. (1998). Bright light therapy in winter depression with or without seasonal anxiety (DSM-IV). Journal of Affective Disorders, 50(2), 109-117.
  3. Weiser, M., Werbeloff, N., Nahon, D., Kaiserman, I., Baharav, E., Ritsner, M., & Levav, I. (2005). Hospitalization for schizophrenia and other psychotic disorders in relation to season of birth and seasonality. Journal of Psychiatric Research, 39(4), 397-401.

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