mrcpsych-0035

A 35-year-old patient with bipolar affective disorder experiences a decline in their mental health and develops hypomania. They were seen in the outpatient clinic two months ago and had their lithium dosage increased from 400 mg to 900 mg per day. Their serum lithium levels were checked again and were found to be 0.1 mmol/L. The patient is physically healthy. What type of non-compliance is most probable in this case?