In considering the risk factors for the development of bipolar disorder, it is useful to separate risk factors into those that are risk factors for lifetime vulnerability (for example genetic factors) and those that are risk factors for the onset of an episode of depression or mania (for example life events). Thus, in determining risk factors for lifetime vulnerability, genetic factors constitute the largest single risk factor. However, if one is considering who is vulnerable to an episode of mania over the next 6 months, genetic factors will play a relatively smaller part and predictions may best be based on other factors such as past history, childbirth, being treated for depression with antidepressant medication, and the approach of spring or summer. Genetic risk factors are discussed further in CMOiei.i.S.SJ..,.
Although organic factors, such as some type of central nervous system damage, are unusual risk factors in young adults, in late-onset bipolar disorder (age of onset more than 50 years) organic disease of the central nervous system is an increasing factor for the development of mania. In younger adults, AIDS and head injury are two important aetiological factors in a limited number of cases of bipolar disorder.
A range of other biological factors are particularly relevant risk factors to the onset of episodes of illness, but they may contribute a relatively small part to lifetime vulnerability. Many women have their first episode of depression or mania in the postpartum period. While a limited number of women may have manic episodes limited to the postpartum period, postpartum episodes of mania are more commonly part of a long-term bipolar disorder and these women will have episodes both precipitated by childbirth and at other times in their life. Indeed, in the postpartum period, having a history of bipolar disorder is one of the strongest risk factors for the development of a postpartum psychosis.
There is substantial evidence that seasonal patterns influence the onset of manic and depressive episodes. There are consistent findings of an excess of manic episodes in late spring and early summer. To date, however, the nature of the environmental factors that influence this late spring, early summer peak of manic episodes is less clear.
There is also substantial evidence that disruptions of normal biological rhythms may precipitate the onset of manic or depressive episodes. This has been documented in relation to international travel involving east-west or west-east travel with disruption of circadian rhythms. Disruption of circadian rhythms through shift-work or other factors, which disrupt the normal sleep cycles, may also be important triggers to the onset of episodes of mania. Indeed, this risk factor is now influencing bipolar disorder management plans by including strategies for minimizing disruptions to 24-h biological rhythms.
Adverse life events have been well documented to be precipitants of manic episodes, as well as depression. It appears that life events are more likely prior to the first or second episode of mania and are less likely later in the course of illness.
While there is substantial evidence that adverse childhood experiences contribute to the later development of major depression, there are relatively few data to support the idea that adversity in childhood influences the development of bipolar disorder.
While there is a paucity of information from population studies as to how subsyndromal symptoms may be a risk factor for bipolar disorder, family studies have long been suggestive of the fact that individuals may manifest subsyndromal symptoms or syndromes well before the clear onset of bipolar affective disorder. Thus, there are individuals who have 'mini-episodes' of mania or depression who are, presumably, at high risk of the subsequent development of bipolar disorder. Similarly, individuals in their teenage years with a pattern of mood swings and cyclothymia are probably also at increased risk of the development of bipolar disorder. Also, individuals with a hyperthymic personality, particularly if they have had past episodes of depression, are a high-risk group for the subsequent development of bipolar disorder.
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Are You Depressed? Heard the horror stories about anti-depressants and how they can just make things worse? Are you sick of being over medicated, glazed over and too fat from taking too many happy pills? Do you hate the dry mouth, the mania and mood swings and sleep disturbances that can come with taking a prescribed mood elevator?