Neurobiological Approach of Catatonia and Treatment Perspectives

Catatonia was described for the first time by Kahlbaum in 1874 (1). It can be defined schematically as a motor dysregulation syndrome accompanied with a behavioral component. There are three main forms of catatonia: (i) akinetic, (ii) hyperkinetic, and (iii) malignant catatonia (2). These various phenotypes of the same syndrome led to a clinical heterogeneousness making the catatonia difficult to recognize and diagnose. It seems, however, that certain clinical signs occur with a greater frequency in catatonia. Indeed, in a study involving more than 230 catatonic patients, the “staring,” was found in more than 80% of cases. Among other frequent signs, were the immobility in 70% of cases, the mutism in 60% of patients, and the withdrawal in 50% of them (3). Various specific scales were developed to allow a more accurate diagnostic approach to catatonia. The Bush-Francis catatonia rating scale is the most commonly used one. It has many advantages: in addition to having a sensitivity of reaching 100% and a specificity between 75 and 100%, it is fast and easy to use in daily clinical practice (4). It is important to note that catatonia is a transnosographic syndrome with various underlying psychiatric and somatic causes. Most common somatic causes include epilepsy, systemic lupus erythematosus, intermittent porphyria, traumatic brain injury, dementia, encephalopathies (autoimmune, paraneoplastic, Hashimoto, etc.) (5). Furthermore, catatonia is found among 10% of psychiatric inpatients (6). Under the influence of Kraeplin, catatonia was linked for a long time exclusively with schizophrenia (7). However, recent epidemiological studies showed that schizophrenia is found only in 20% of catatonic cases while mood disorders underlie 45% of cases (8). Catatonia is also frequent in children and adolescents, particularly in autism spectrum disorders where the prevalence varies between 12 and 17% (9). Despite these clinical and epidemiological facts, few data exist concerning the exact pathophysiological mechanisms underlying this syndrome. In this paper, we will make the synthesis of the existing data concerning the neurocognitive and neurobiological mechanisms involved in the akinetic forms of catatonia.