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The New Therapist
with Anthony D. Smith, LMHC

Improving Diagnostic Accuracy: Medical Mimicry, Part 3

In Medical Mimicry, Parts 1 and 2, we began exploring how medical conditions affect mental health and the importance of evaluating for them as symptom sources. This included two of three crucial items to keep in mind when thinking about medical contributions. Today, we examine the third:

Is the symptom presentation very unusual?

Evaluators should be vigilant for the following 4 items:

  1. Was there a very rapid/acute symptom onset? This, especially in the absence of any previous experience of the symptoms.
  2. Do symptoms inexplicably come and go?
  3. Was age of onset unusual? It would be strange, for instance, for someone to develop symptoms of OCD or a Personality Disorder in their 30’s.
  4. Are symptoms themselves exceptional? For example, is someone experiencing tactile, olfactory, or gustatory (feel, smell, taste) hallucinations? These are fairly rare in Schizophrenia-spectrum disorders and mood disorders with psychotic features, where we most often encounter hallucinatory activity. Such hallucinations, especially in the absence of any verified history of psychosis-related diagnoses or trauma history where it could be part of a reliving-the-trauma experience, are often indicative of an underlying medical cause like a tumor or head injury.

The case of Bess:

Bess, a 35-year-old, single, working mother, sought therapy because she noticed a new moodiness about herself. She had never required mental health care previously. Although she had some stress in her life, this was not like the irritability she usually felt when under pressure. All of a sudden, for the past month, she found herself  fluctuating daily between feeling a lethargic sadness that would randomly give way to feeling giddy and resltess.  She was never totally down and out or out of control, but complained of feeling like a rapidly-undulating rollercoaster. At first glance, Dr. H, an experienced practitioner specializing in mood disorders, thought Bess might have a Bipolar spectrum disorder. Though onset is usually much earlier, it is not unheard of for the conditions to surface in someone’s 30’s. Dr. H was concerned, however, at how fast they came on, and the rapidity with which the symptoms fluctuated. It was not normal to Bipolar presentations, even Cyclothymia, where symptoms chronically shift every 2-3 days. At the end of their first session Dr. H explained his observation to Bess, and asked if he could speak with her primary care physician to explain his concern. Upon medical examination doctors discoverd Bess had a tumor on her pituitary gland, which, similar to the thyroid, controls hormones.

Bess’ diagnosis would be Bipolar Disorder Due to Pituitary Tumor, With Features of Cyclothymia. We know that hormones have a significant effect on mood disorders. In fact, according to mood disorder expert Joseph Shannon, Ph.D. (2016), prior to menopause, rates of depression are a 2:1 female to male ratio. Post-menopausal populations exhibit an equal ratio. For Bess, the tumor was influencing a strange pattern of hormone release and the fix was surgery, not psychiatric medications and therapy.

Stranger Things

Perhaps some of the most interesting cases of medical conditions disguised as psychological problems are Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococci (PANDAS) and anti-NMDA encephalitis due to a teratoma. PANDAS occurs in children who have had frequent strep infections. In people with PANDAS, for some reason, the strep infection does not just affect the throat, and may enter the brain. Antibodies rush in to fight it, not only destroying the bacteria, but also the brain tissue (Columbia University, 2015). This seems correlated with sudden onset of symptoms of aggression and impulsivity, vocal or motor tics like in Tourette’s Syndrome, and repetitious behaviors and obsessions as in OCD (Swedo, 2015; Thienemann, 2017). Thankfully antibiotics often help, and some get their tonsils removed as a long-term solution. In people with actual OCD or Tourettes’s, strep infections may exacerbate them.

The second condition, believed to be rare, is inflammation of the brain related to a teratoma (an unusual tumor, often found on an ovary, consisting of various tissues including bone, teeth and hair). Initial symptoms can include seizures and other neurological problems, but psychotic and manic symptoms are usually prominent (Yen, 2012). Journalist  Susana Cahalan’s memoir, Brain on Fire, details the very strange journey from evaluation to recovery of this bizarre condition. It also sheds light on the importance of quick medical evaluation in unusual psychiatric presentations.

Other medical conditions, like malaria, can cause hallucinations due to inflammation of neural networks (encephalitis) during high fevers. Syphilis can also make a Schizophrenia-like presentation. In an ironic twist, malaria was once used to correct syphilis. In the 1800’s, it was discovered that if people who were psychotic due to syphilis developed high enough fevers, their psychosis subsided and the syphilis disappeared. The prescription? “Pyrotherapy”: induce malaria in syphilitic patients. The sustained high body temperature “burned out” the bacteria causing syphilis.

While chances are rare you’ll encounter a hallucinating patient with an STD in need of pyrotherapy, it is not so far-fetched that a patient could have a more general medical condition causing, or exacerbating, a psychological disturbance. Indeed, I have more than once recommended a medical evaluation, such as in the aforementioned panic/diabetic presentation. Learning what medical conditions might mimic the diagnosis you’re considering is another step towards strengthening your diagnostic capability. You may not be a medical professional, but asking if the patient has medical conditions is not simply perfunctory information gathering. It can lead to their psychological relief and maybe even save a life.


Columbia University Irving Medical Center. How Recurrent Strep A Infections Affect the Brain. (2015). Retrieved from

Diagnostic and Statistical Manual of Mental Disorders: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, VA: American Psychiatric Association, 2013.

Shannon, J. (2016, September). Reasoning With Unreasonable People: Focus on Disorders of Emotional Regulation. Brattelboro Retreat (organizer). Continuing education seminar conducted from Agawam, Massachusetts.

Swedo SE, Seidlitz J, Kovacevic M, et al. Clinical presentation of pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections in research and community settings. J Child Adolesc Psychopharmacol. 2015;25(1):26-30. doi:10.1089/cap.2014.0073

Margo Thienemann, Tanya Murphy, James Leckman, Richard Shaw, Kyle Williams, Cynthia Kapphahn, Jennifer Frankovich, Daniel Geller, Gail Bernstein, Kiki Chang, Josephine Elia, and Susan Swedo. Journal of Child and Adolescent Psychopharmacology. Sep 2017.566-573.

Yen, L.K., Hsing, F. T., Ming, C.L., Chien HL, & Yien, L.Y. Anti-NMDA receptor encephalitis with the initial presentation of psychotic mania [Abstract]. Journal of Clinical Neuroscience. 2012; 19 (6):896-898.

Improving Diagnostic Accuracy: Medical Mimicry, Part 3

Anthony Smith, LMHC

Anthony Smith is a licensed mental health counselor in Massachusetts with 20 years of experience. He has worked in facilities and in private practice performing therapy and diagnostic evaluations across a wide array of populations both demographically and clinically. This includes 17 years in the forensic arena, where he currently provides assessments for the juvenile courts. Aside from interest in the intersection of psychology and law, Anthony is particularly in interested differential diagnosis and supervision of new practitioners. He regularly teaches abnormal psychology and creates courses on the lived experience of people with mental illness, along with supervising graduate student counselling practicums at a local university. When not providing clinical services, teaching or blogging, Anthony can be found hiking and fly-fishing around the Northeast and American West.


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APA Reference
Smith, A. (2020). Improving Diagnostic Accuracy: Medical Mimicry, Part 3. Psych Central. Retrieved on September 18, 2020, from