Multiple sclerosis is a chronic inflammatory disease of the central nervous system characterised by progressive demyelination. It is the most common cause of neurologic disability in young and middle-aged adults.1
Ninety-five per cent of patients show some form of neuropsychiatric symptoms.2
This could be in the form of depression (79%), agitation (40%), anxiety (37%), irritability (35%), apathy (20%), euphoria (13%), disinhibition (13%), hallucinations (10%), aberrant motor behaviour (9%) or delusions (7%).1
Two to three per cent of patients with multiple sclerosis can present with psychosis.3
Psychosis in multiple sclerosis differs from schizophrenia in that it has an onset at a later age, quicker resolution, fewer relapses, better response to treatment and a better prognosis.1
Available literature on psychosis in multiple sclerosis suggests an involvement of lesions in temporal areas. In their study, Fricchione et al4
emphasise the central role of hippocampus, a periventricular medial temporal lobe structure, in secondary organic delusional syndromes. Patients with epilepsy, who have left temporal lobe epileptogenic lesions, are especially prone to schizophrenia-like psychosis.5
In his study, Flor-Henry6
reports that right temporal lobe lesions are associated with features similar to psychotic depression.
In our case, Mr C had lesions present in both temporal lobes (left more than right). Based on the literature, it can be suggested that while left temporal lobe lesions accounted for his schizophrenia-like psychosis, the right temporal lobe lesions can account for his nihilistic delusions and self-injurious behaviour.
Although the presentation of Mr C can also be explained in terms of schizophrenia, considering a positive family history and use of cannabis, the fact that Mr C not only had decreased vision of his right eye, indicating an exacerbation of his multiple sclerosis, his MRI head confirmed new active lesions in the temporal lobe. The case emphasises the importance of investigating for an organic cause in a first-episode or new onset psychosis. This would not only help us to come to a correct diagnosis, but also to tailor an appropriate treatment plan for an optimum response.
Treatment for psychosis in multiple sclerosis is mainly symptomatic, with atypical antipsychotics preferred over typical antipsychotics because of better tolerability. There have been only few published trials on treating psychosis in multiple sclerosis, but risperidone,7
have reasonable efficacy. Steroids can also be used to decrease the inflammatory process; however, steroid-induced psychosis should be kept in mind in such cases. Also medications to reduce the progression of multiple sclerosis and to improve clinical outcome should be continued.
- Two to three per cent of patients with multiple sclerosis can present with psychosis.
- Psychosis in multiple sclerosis is associated with left temporal lobe lesions.
- Treatment is mainly symptomatic and involves antipsychotics along with medications to reduce the progression of multiple sclerosis.
- Steroids can be used to decrease the inflammatory process associated with multiple sclerosis but clinicians should be cautious of steroid-induced psychosis.