A case of multiple sclerosis presenting as first-episode psychosis in a young person

To the Editor

A 15-year-old Australian-born male of Sudanese descent presented with first-episode psychosis, characterised by 2 months of perceptual disturbances including auditory, visual and tactile hallucinations and persecutory delusions. He also presented with negative symptoms of restricted affect, alogia, amotivation and asociality. His symptoms were associated with a significant decline in his functioning, particularly his educational attainment, as he had to repeat a year at school.

His medical history included a diagnosis of hiatus hernia causing epigastric pain and gastro-oesophageal reflux, for which he underwent fundoplication surgery. He had no other significant medical issues. Initial routine blood investigations of full blood examination (FBE), urea/electrolytes/creatinine (UEC), liver function test (LFT), fasting glucose and fasting lipids were within normal parameters.

There were no obstetric complications and no developmental delays observed and there was no history of adversity reported. He was performing well academically premorbidly. There was no known family history of mental illness. He also denied any substance use.

He was initially prescribed risperidone 1 mg and this was titrated up to 4 mg, at which point a reduction in positive symptoms was observed. However, his functioning continued to deteriorate and the impression was that this was due to negative symptoms, specifically amotivation and anergia. However, he subsequently ceased the risperidone of his own accord and this was followed by a worsening of positive psychotic symptoms. He then agreed to a trial of aripiprazole 10 mg.

Throughout his care, he continued to experience multiple physical symptoms, and to investigate these further, he had further tests, including a magnetic resonance imaging (MRI) of the brain. This found multiple lesions that were typical of demyelination and hence indicative of multiple sclerosis (MS), which was confirmed by a neurologist with a repeat MRI brain scan and lumbar puncture. Physical examination performed by the neurologist did not reveal any focal abnormalities. He commenced natalizumab and he discontinued aripiprazole of his own accord. Since commencing natalizumab, his psychotic symptoms significantly improved and remission was achieved. His functioning also improved and he commenced vocational training.

MS is a disease characterised by focal areas of demyelination that can affect any part of the central nervous system and result in varied signs and symptoms. There can be an association between MS and psychosis; however, it is relatively uncommon (Gilberthorpe et al., 2017). In this case, the temporality between the improvement of psychotic symptoms and treatment of MS would suggest an association. Furthermore, it is likely that what were presumed to be negative symptoms, were more likely symptoms of fatigue and lethargy that are common in MS. Less than 1% of neuroimaging in first episode of psychosis yields clinical significance, and therefore, neuroimaging should only be performed when clinically indicated (Forbes et al., 2019). We propose that neuroimaging could be considered in the presence of apparent persistent negative symptoms in a young person, as MS is a rare but important differential diagnosis of first presentation of psychosis.