Normally described in settings of neurologic injury, pseudobulbar affect (PBA) is characterized by uncontrollable outbursts of laughing, crying, or both, that are unrelated to, or disproportionate to the subjective emotions felt by the patient. We describe here, a unique case of PBA occurring in the context of chemotherapy use.

To introduce awareness of this possible complication with the use of chemotherapy, and to consider PBA as a differential in the setting of consultation liaison psychiatry.

We describe a 52 year-old Chinese lady, without significant past psychiatric history, who was admitted to our hospital for the initiation of a course of chemotherapy in the treatment of recurrent breast carcinoma. She was referred to the Consultation Liaison Psychiatry team, presenting with episodic emotional lability. the symptoms were observed to last 6 days at the most, and always occurring on the second day post-chemotherapy. the affective dysregulation was out of proportion to her actual reported mood. We will discuss briefly about PBA and review the relevant literature.

After a short regime of benzodiazepines and reassurances given, she completed her planned course of 6 cycles of chemotherapy.

Pseudobulbar affect is known to occur in a variety of diseases of the central nervous system such as multiple sclerosis, cerebral vascular disease, as well as brain tumours. This case illustrates that medications could also cause PBA, albeit a transient course. We advocate further studies to investigate the pharmacodynamics which may be a clue to the mechanisms mediating this difficult condition.