People with mental disorders (such as schizophrenia, which is characterized by symptoms of psychoses) are at greater risk than the general population for exposure to infectious diseases, including TB (51). Psychosis is characterized by distorted thoughts and perceptions, disturbed emotions and behaviours, and the possibility of incoherent or irrelevant speech (see Table 1). Delusions, which are fixed false beliefs not shared by others in the person’s culture, are another psychosis symptom, as is hallucination – a severe alteration in the way a person perceives reality, typically exhibited as sensory experiences that do not correspond to reality, such as seeing or hearing things in the absence of an external stimulus.
In the case of drug-resistant TB, symptoms of psychoses can be triggered as a side effect of some antiTB medications, including cycloserine, high-dose isoniazid and fluoroquinolones. Side effects resulting from anti-TB medications may include visual or auditory hallucinations, with or without delusional elaboration (26). Sometimes it may present with clouding of consciousness, intellectual decline, predominant disturbance of mood, or marked delusions. In case of these presentations, it is best to refer to a mental health specialist for assessment (26). In general, psychosis is best managed either by or under the supervision of a mental health specialist. Where resources are available, a baseline assessment for psychosis may be considered prior to the initiation of treatment with cycloserine, high-dose isoniazid and fluoroquinolones. This may aid providers in determining whether onset of symptoms of psychoses is associated with an anti-TB agent; and for individuals screening positive for symptoms of psychoses at baseline, close coordination between TB and mental health services is required to manage potential exacerbation of symptoms. Since the onset of psychosis as a reaction to anti-TB medications is often very rapid, having a baseline assessment can help providers determine whether the symptoms may be related to a specific anti-TB agent or a mental disorder. For people with psychotic symptoms at baseline, very careful monitoring is required to ensure that these symptoms are not exacerbated by these anti-TB medications. For additional guidance, refer to the WHO Guidelines for the management of physical health conditions in adults with severe mental disorders (38).
If the symptoms of psychoses do not improve after the suspected anti-TB medication has been stopped for 1–2 weeks, anti-psychotic pharmacological intervention should be considered, in consultation with a mental health specialist (see Table 1 for management of psychotic symptoms). Any adjustment to the regimen should be made according to the principles for treatment regimen design (see WHO operational handbook on tuberculosis, Module 4: Treatment - Drug-resistant tuberculosis treatment, 2022 update) (49).