Mania genetic factors

Mania, manic-depression and depression, which comprise the affective disorders, are relatively common it has been estimated that there is an incidence of at least 2% in most societies throughout the world. There is good evidence to suggest that genetic factors play a considerable role in predisposing a patient to an affective disorder. In a seminal Danish twin register study, in which the incidence of affective disorders was determined in all twins of the same sex born in Denmark between 1870 and 1920, a total of 110 pairs of twins were identified in which one or both had manic-depression. The concordance rates, that is the rate of coexistence of the disorder in twin pairs, for all types of affective disorder were found to be... 

I want to reemphasize that drug-induced disturbances in mood or in behavior should be viewed as genuine neurological disorders rather than as vague mental illnesses. The capacity of speculative biochemical imbalances or genetic factors to cause or contribute to mania or depression remains unproven. Nor do we know the specific biochemical or neurological mechanisms whereby psychoactive substances cause mental disturbances. But the capacity for psychoactive substances to disrupt brain function and hence mental function is beyond dispute. Furthermore, a great deal of empirical data confirm their capacity to cause disinhibition, mania, depression, and other mental phenomena associated with violence toward oneself and others, as well as other destructive behaviors. 

BD occurs in 1% of the population and affects an individual s emotional response, with symptoms cycling between depression and mania. It is a complex genetic disease thought to require additional environmental factors for onset. Gene expression studies in BD have identified many changes in common with SZ, including oligodendrocyte abnormalities [140] and mitochondrial dysfunction [141]. 

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