Adult-onset metachromatic leukodystrophy is often a diagnostic challenge to many clinicians. It may be presented with psychiatry symptom before other evidences of leukodystrophy are uncovered. We report a 53-year-old patient who presented with 7-year history of manic-like presentation in addition to progressive neurocognitive deterioration. Diagnosis was made eventually with neuroimaging. Mutational analysis showed compound heterozygous of ARSA gene. This case demonstrated the challenge in diagnosing this condition due to its complex neuropsychiatric presentation.