Autism and Bipolar
Bipolar and Autism
Bipolar and Autism co-occur at high rates (about 3x times more for Autists than the general population). Here is a rundown of some of the overlap/studies.
Genetic Overlap
Recent studies suggest Autism and Bipolar share genetic links and can commonly co-occur in families (Goes et al., 2016; Zeliadt, 2018). Other studies have demonstrated genetic links between schizophrenia, bipolar and autism, and identify that they share similar genetic expression patterns in the brain (Zeliadt, 2018). All three of these conditions activate certain genes in the astrocytes--star-shaped brain cells that perform key functions in the central nervous system (Gandal et al., 2018). Similarly, all three conditions suppress genes that help synapses signal to one another (the connection point between nerve cells in the brain). So neurologically they have similarities (and thus there are many overlapping traits of the conditions), and genetically they are connected meaning there likely co-occur at higher rates.
Rates of Co-Occurrence
Based on a metanalysis including several studies Skokauskas estimates approximately 7% of autistic individuals also have bipolar. This is nearly 3x the percentage of people in the general (Skokauskas, 2015).
In a study involving 157 youth (7-17) with Bipolar 30% also met the criteria for Autism (Joshi et al., 2013).
In a study involving 787 adults with Bipolar 1 diagnoses, 47.2% showed a clinically significant level of Autistic Traits (Abu-Akel et.al, 2017).
In a study involving 727 children, 21% with pervasive developmental disorder also met criteria for mania bipolar (Raja & Azzoni, 2008) (compared to 4% of the general population).
Therapeutic and Medication Implications
Individuals with both often present differently than those with “pure” bipolar or “pure” autism. As such they are vulnerable toward missed and misdiagnosis and may be disproportionately misdiagnosed with personality disorders (Raja & Azzoni, 2008).
Lithium, widely used to treat Bipolar, can be a highly toxic medication. Autists bodies can be more sensitive to mediations and toxics and therefore may have more extreme reactions. When a person is put on lithium, it is vital they communicate with their loved ones and doctors about their experiences with the medication. If an Autist struggles with interoception (difficulty observing body signals) or has communication differences/difficulties is unable to communicate about the medication's troublesome side effects, this can be dangerous. Some studies have suggested that starting with anti-seizure medication, mood-stabilizing medications with low-dose of anti-psychic medication are safer for Autists. If Bipolar is diagnosed but the Autism remains undetected such precautions around toxicity, side-effects and medicine may be disregarded (National Autistic Society UK).
References
Cross-Disorder Group of the Psychiatric Genomics Consortium. Genomic relationships, novel loci, and pleiotropic mechanisms across eight psychiatric disorders. Cell. 2019;12;179(7):1469-1482.e11. doi:10.1016/j.cell.2019.11.020
Goes FS, Pirooznia M, Parla JS, et al. Exome sequencing of familial bipolar disorder. JAMA Psychiatry. 2016;73(6):590–597. doi:10.1001/jamapsychiatry.2016.0251
Joshi G, Biederman J, Petty C, Goldin RL, Furtak SL, Wozniak J. Examining the comorbidity of bipolar disorder and autism spectrum disorders: a large controlled analysis of phenotypic and familial correlates in a referred population of youth with bipolar I disorder with and without autism spectrum disorders. J Clin Psychiatry. 2013;74(6):578-586. doi:10.4088/JCP.12m07392
Raja, M., Azzoni, A. Comorbidity of Asperger's syndrome and Bipolar disorder. Clin Pract Epidemiol Ment Health 4, 26 (2008). https://doi.org/10.1186/1745-0179-4-26
Skokauskas N, Frodl T. Overlap between autism spectrum disorder and bipolar affective disorder. Psychopathology. 2015;48:209-216. doi:10.1159/000435787
Wozniak J, Biederman J, Faraone S, Frazier J, Kim J, Millstein R, Gershon J, Thornell A, Cha K, Snyder JB: Mania in children with pervasive developmental disorder, revisited. J Am Acad Child Adolesc Psychiatry. 1997, 36: 1552-1560. 10.1097/00004583-199710000-00002.
Zeliadt, N. (2018) Autism Shares Brain Signature with Schizophrenia and Bipolar Disorder. Spectrum Neurology in Scientific American. Retrieved on February 21, 2022 at: https://www.scientificamerican.com/article/autism-shares-brain-signature-with-schizophrenia-and-bipolar-disorder/