Schizophrenia and anxiety: yes, they are relatives not just neighbours

We are thrilled to see that the study of anxiety in people with psychotic spectrum disorders is gaining recognition. The paper published by Dr Hall provides a good insight about common grounds between the two disorders and highlights the advantages of studying anxiety in those with psychotic disorders.¹ One of the problems of studying anxiety is that it is often overshadowed when the diagnosis of schizophrenia is given to a patient. However, anxiety is often underdiagnosed and untreated regardless of the primary diagnosis, which represents a significant economic burden. One of the possible hypothesis for this diagnostic delay is the fact that current anxiety nosology is characterised by many subjective cognitive (anticipatory anxiety), behavioural (avoidance behaviour) and psychological (worry, fear) aspects of anxiety, but the often-comorbid somatic or physical conditions are neglected.

Our group found that anxiety disorders are indeed very common among patients with schizophrenia, with estimated prevalences of 30%.² We also found that those with comorbid anxiety disorders were more likely to display positive symptoms and greater fears, suggesting that those patients with comorbid anxiety had a specific profile of symptoms.³ Interestingly, patients with this phenotype experienced greater joint hypermobility syndrome, which has been associated with anxiety in clinical and non-clinical populations. Our group initially described this associated in 1988 in a letter to the Lancet ⁴ and this field has expanded significantly during past years. This phenotype is rich in somatic and bodily complaints that seems to be mediated by an autonomic nervous system dysfunction, and many of these patients experience stress-related illnesses such as chronic pain, irritable bowel syndrome or dysautonomia. Other hypothesised underlying mechanisms behind this association include genetic risks, atypical body perception profiles, increased interoception and exteroception, and decreased proprioception.⁵ Neuroimaging studies showed that joint hypermobility is associated with the expression of anxiety through autonomic hyper-reactivity linked to aberrant engagement of the amygdala and insula.⁶

Taking into account that heightened anxiety may be important in both the development of psychosis and psychosis relapses as described by Dr Hall, it is imperative to ensure a proper anxiety assessment. Joint hypermobility syndrome can be a helpful marker for identifying somatic and bodily complaints, and it is particular significant in schizophrenia because it is associated with greater fears and anxiety severity and higher frequency of positive symptoms. In addition, this phenotype may open opportunities for new therapeutic interventions that should be further studied in subsequent studies.