Diagnosing Schizoaffective Disorder vs Dementia

Case study exhibits difference in diagnosis and treatment

By Ardeshir Hashmi, MD

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A 69-year-old man presented for a second opinion after being diagnosed with frontotemporal dementia (FTD). His comorbidities included hypertension, diabetes mellitus type 2 and osteoarthritis.

According to medical records, the patient had been diagnosed with dementia because he scored 19 of 30 on Montreal Cognitive Assessment (MoCA) testing and his brain MRI displayed features consistent with FTD. The patient commenced on donepezil with no improvement in symptoms over time.

The patient had experienced changes in short-term memory over five years. He reported needing help with managing finances and taking medications. He had gotten lost while driving on familiar roads.

Most concerning for his family was his agitation/anger, paranoia and apathy. Agitation episodes were directed toward his wife, grandchildren and other drivers and were exaggerated in comparison to the associated anger trigger. He exhibited significant paranoia toward his wife as well as people on television news programs. Apathy resulted in an almost catatonic, “trance-like” state at times. He also exhibited anhedonia (no longer pursuing interests he used to enjoy) as well as low motivation to shower, get dressed and go out of his home. Appetite and sleep were poor. His sympathetic/empathetic nature was preserved, however.

The patient also had sporadic episodes of elation, dancing incessantly while grocery shopping, for example. While sadness had been pervasive the prior five years, episodes of paranoid delusions were unrelated to episodes of elation. There was no inappropriate disinhibited behavior at any point. Nor was there any obsessiveness, other than a tendency to hoard things.

There was no family history of dementia.

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On our clinical assessment, the patient remarkably scored 29 of 30 on repeat MoCA, consistent with normal age-related physiological memory changes. A comprehensive physical exam, including neurological assessment, was entirely within normal limits. Serological diagnostic workup for any reversible etiologies for dementia was negative. A urine toxicology screen was negative for substance use.

MRI brain images from the prior evaluation were reviewed and found to show no frontal or temporal region atrophy — only age-appropriate changes in brain volume.

About FTD

FTD is a clinical umbrella term for three FTD subtypes:

  1. Behavioral-behavioral variant FTD (bvFTD) and primary progressive aphasia.
  2. Non-fluent aphasia.
  3. Semantic variants.

Non-fluent aphasia is characterized by significant impairment of articulation. The semantic subtype involves difficulty with single-word comprehension (while whole-sentence comprehension remains preserved). The patient in this case had none of these symptoms.

Per the 2011 International Behavioral Variant FTD Criteria Consortium, at least three of these six features are needed to diagnose bvFTD:

  • Disinhibition (e.g., hypersexuality, urinating in public).
  • Apathy/inertia.
  • Loss of sympathy/empathy.
  • Perseverative/compulsive behaviors.
  • Hyperorality (e.g., binge eating, carbohydrate cravings, increased alcohol consumption or cigarette smoking, putting excessive amounts of food in mouth).
  • Dysexecutive neuropsychologic profile.

The patient met one or, at most, two of these criteria. In addition, neuroimaging did not support an FTD pattern of frontal and temporal lobe atrophy, and donepezil had no role in his treatment.

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About schizoaffective disorder

Per the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), a diagnosis of schizoaffective disorder requires meeting at least two of these primary criteria for schizophrenia:

  • Delusions.
  • Hallucinations.
  • Disorganized speech (speech that is easily derailed or incoherent).
  • Grossly disorganized or catatonic behavior.
  • Negative symptoms (e.g., flat expressions, anhedonia, lack of motivation/avolition, and other experiences that are “taken away” from the person).

The patient met three of these clinical criteria: paranoid delusions, catatonic behavior and negative symptoms.

In addition, he met all of the following DSM-5 criteria distinguishing schizoaffective disorder:

  • A major mood episode (either major depression or mania) that lasts for an uninterrupted period of time.
  • Delusions or hallucinations for two or more consecutive weeks without mood symptoms sometime during the life of the illness.
  • Mood symptoms for the majority of the illness.
  • Symptoms not caused by substance use.

The patient and his wife were advised that the patient had schizoaffective disorder, not FTD.

Treating schizoaffective disorder

The patient commenced on an atypical antipsychotic as well as a mood stabilizer, divalproex sodium. A mood stabilizer was chosen because the patient’s mood domain had a bipolar pattern, and an antidepressant could potentially trigger full-blown manic episodes.

Over the past six months, the patient has responded favorably to this treatment regimen. His paranoid delusions and anhedonia/apathy have resolved completely. He is much more socially engaged and is eating and sleeping better. His anger episodes have significantly improved. His overall quality of life has greatly improved, as have his family relations.