|Maybe I'm better suited as a brunette? @ Wikipedia|
That was the primary finding reported by Vannucchi and colleagues  based on their systematic review of the relevant peer-reviewed research literature in this area. They found that the prevalence of BD ranged between 6 - 20% depending on the studies included for review. They also reported that "BD assumes peculiar features which might shape its under-recognition or misdiagnosis" in cases of AS. In short, this is an area which perhaps requires a little more investigation.
Bipolar disorder, previously called manic depression, is concerned with mood and how it can 'swing' between extremes of depression and mania. Although discussions about the 'causes' of BD parallel discussions on the causes of lots of conditions which manifest psychiatric symptoms, research like that from Faedda and colleagues  talking about "generalized anxiety disorders" as risk factors for BD might be important. I've mentioned BD a few times on this blog: be it in relation to the genetic 'common ground' of psychiatry (see here) or the interesting work coming out of Johns Hopkins on gastrointestinal (GI) inflammation and immune activation in cases of BD (see here). Suffice to say that there may be quite a bit more to BD  than what just goes on the old grey-pinkish matter.
Asperger syndrome probably needs little introduction to regular readers of this blog. In case you don't know, here is the UK National Autistic Society (NAS) description of the condition. As per the growing acceptance that comorbidity, some medical comorbidity, might be elevated when a diagnosis on the autism spectrum is received (see here), there is also a realisation that the presence of autism or AS might also elevate the risk of psychiatric comorbidity too. The paper by Rosenberg and colleagues  (open-access here) corroborates this view, and indeed highlights how BD represents one such comorbid psychiatric diagnosis. At the risk of going off at a tangent, I was also intrigued by the finding by Rosenberg et al that: "Autistic regression was associated with lower risk of any comorbidity" which might imply different factors or weightings (genetic, environment) being involved in different types of autism...
The comment in the Vannucchi review about "atypical presentation" of BD in cases of AS got me thinking quite a bit. The case report detailed by Frazier and colleagues  (open-access) offers some insight into how this atypical presentation might manifest; in particular: "Bipolar disorder should be entertained as a possible diagnosis when there is deterioration in cognition, language, behavior, or activity; when there is a clear pattern of fluctuation or cyclicity in activity, behavior, and interests (with "good times" and "bad times"); and when observed behavior indicates a mood problem". They go on to mention: "His affective [mood] disorder exacerbated the underlying symptoms of Asperger’s [syndrome]" and that: "Once comorbid bipolar disorder was diagnosed and appropriate treatment occurred, Abraham gradually began to recover and his self-injury, aggression, and intense pressured obsessiveness disappeared". Self-injury and aggression eh?
I'm not necessarily saying that everyone with AS who has BD will fit into the description provided by Frazier et al in terms of presentation or intervention (which, by the way, was made up of "oral clonazepam... lithium... and risperidone"). But this and other reports do offer some good starting points to looking at the issue of BD as comorbid to cases of AS or other autism spectrum diagnoses. Oh and if one is to assume that something like immune function might be related to cases of BD, maybe, just maybe, one might consider looking at some of the correlates of immune activation as per reports like the one from Emily Severance and colleagues  on food potentially being a factor. Food and psychiatry... now where have I heard about that before?
Music to close. When You Were Young by The Killers.
 Vannucchi G. et al. Bipolar disorder in adults with Asperger׳s Syndrome: A systematic review. J Affect Disord. 2014 Jul 8;168C:151-160.
 Faedda GL. et al. Clinical risk factors for bipolar disorders: A systematic review of prospective studies. J Affect Disord. 2014. July 18.
 Rege S. & Hodgkinson SJ. Immune dysregulation and autoimmunity in bipolar disorder: Synthesis of the evidence and its clinical application. Aust N Z J Psychiatry. 2013 Dec;47(12):1136-51.
 Rosenberg RE. et al. Parent report of community psychiatric comorbid diagnoses in autism spectrum disorders. Autism Res Treat. 2011;2011:405849.
 Frazier JA. et al. Treating a child with Asperger's disorder and comorbid bipolar disorder. Am J Psychiatry. 2002 Jan;159(1):13-21
 Severance EG. et al. Immune activation by casein dietary antigens in bipolar disorder. Bipolar Disord. 2010 Dec;12(8):834-42.
Vannucchi G, Masi G, Toni C, Dell׳Osso L, Erfurth A, & Perugi G (2014). Bipolar disorder in adults with Asperger׳s Syndrome: A systematic review. Journal of affective disorders, 168C, 151-160 PMID: 25046741