The psychiatrist rules out a behavioral exacerbation of autism based on an interview with Mr. S’s family and established rapport from treating him for several years. Mr. S’s family reports that many of his behaviors are not new but that the increased drive and intensity is worrisome. Further, his family cannot identify any stressors or precipitants for the behaviors and reports that offering preferred reinforcers did not help. An anxiety disorder is ruled out because according to the family, Mr. S’s drive to constantly move and complete rituals is fueling his anxiety. Schizoaffective disorder is ruled out because Mr. S denies auditory hallucinations and has not been observed responding to internal stimuli.
His Bush-Francis Catatonia Rating Scale (BFCRS) score is 26, which suggests a high likelihood of catatonia. Based on the BFCRS score, Mr. S’s psychiatrist makes the diagnosis of hyperkinetic catatonia.
The authors’ observations
The psychiatrist determined that Mr. S had been misdiagnosed with bipolar disorder at age 13. At that time, he had experienced his first episode of hyperkinetic catatonia and his symptoms decreased after he received lorazepam in the ED. However, the treatment team did not correctly identify this, most likely due to limited knowledge of catatonia among emergency medicine clinicians.
This case exemplifies a cognitive error of premature closure. Rather than considering catatonia as a complication of autism when Mr. S was 13, the clinicians added a second psychiatric diagnosis of bipolar disorder.Although premature closure errors generally occur when the physician assumes the patient is having a common complication of a known illness,1 in Mr. S’s case, the opposite occurred.
One helpful model for conceptualizing catatonia is to think of it as a basal ganglia disorder, with lesions in the basal ganglia thalamocortical tracts and the anterior cingulate/medial orbitofrontal circuit. Disrupting these pathways can result in symptoms such as mutism or repetitive and imitative behaviors. This is likely due to decreased disinhibition by gamma-aminobutyric acid (GABA), resulting in a hypodopaminergic state. This explains why benzodiazepines, which act to increase GABA, are effective for treating catatonia, and antipsychotics that act to decrease dopamine can exacerbate symptoms. Fricchione et al2 developed a model to visually represent the neurobiologic pathophysiology of catatonia (Figure2).
Continue to: Underlying causes of catatonia