By: Anna Yeh
Bipolar disorder is a severe mental illness that involves drastic shifts in mood, energy and concentration. These moods involve waves of mania, and depression. Manic episodes involve extreme highs, irritability and periods of high energy. During these episodes often times lead a person to feel important, active. It is important to note that during these manic episodes, a person might have a heightened appetite for food, drinking and other pleasurable activities, which may result in the abuse of mind altering substances.
There are three types of bipolar disorder, but studies have shown that Type I has a strong genetic factor of inheritance. The heritability of bipolar disorder is estimated to be around 60-80%, indicating a substantial genetic influence. However, it is important to note that bipolar disorder does not follow a simple Mendelian inheritance pattern, where a single gene is responsible for its development. Instead, it is considered a complex genetic disorder, influenced by multiple genes and their interactions, as well as environmental factors. Various genes associated with neurotransmitter regulation, circadian rhythms, and synaptic function have been linked to bipolar disorder. While research is still in progress, there has been found a positive association in chromosomes 5, 12, 13, 18, and 22. These genes, such as DRD1,4 and DAT1 play a role in the dopaminergic pathway. The neurotransmitter, dopamine, is involved with the brain’s reward system. Many drugs involve or mimic dopamine in some way, which is the main reason why they are so addictive.
Studies have shown that there is a high comorbidity rate with bipolar disorder and alcohol use disorder. Along with alcoholism, nicotine dependence has been shown to have a genetic linkage to bipolar disorder. This means that those with bipolar have an increased chance of inheriting alcohol and nicotine dependence than their non-bipolar relatives. This suggests a strong overlapping genetic pathway for both traits. About 50% of those with a predisposition to bipolar disorder also have a predisposition for alcohol use disorder.
Both the manic and depressive states of bipolar disorder put people at a higher risk to turn to drug abuse. During manic episodes there is a heightened urge to pleasure, and one might seek that through alcohol, nicotine or drug abuse. However, during depressive episodes dopamine levels drop drastically. In order to pursue the reward and pleasure pathways, dopamine can be replaced by drugs that mimic siad neurotransmitter. Managing both bipolar disorder and addiction requires a comprehensive and individualized approach. By addressing both conditions simultaneously, individuals can work towards achieving stability, improved quality of life, and long-term recovery.
References:
NIMH (2023) Health Topics, Bipolar Disorder National Institute of Mental Health https://www.nimh.nih.gov/health/topics/bipolar-disorder
Escamilla, M. (2008) Genetics of Bipolar Disorder Dialogues Clin Neurosci 10(2): 141-152 doi: 10.31887/DCNS.2008.10.2/maescamilla
Carmiol, N., Peralta, J. M., Almasy, L., Contreras, J., Pacheco, A., Escamilla, M. A., Knowles, E. E., Raventós, H., & Glahn, D. C. (2014). Shared genetic factors influence risk for bipolar disorder and alcohol use disorders. European psychiatry : the journal of the Association of European Psychiatrists, 29(5), 282–287. https://doi.org/10.1016/j.eurpsy.2013.10.001
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