A patient with symptoms of unresponsiveness, rigidity, and sweating is being treated for bipolar disorder. What is the next best step?

The correct next step in this scenario is to discontinue risperidone. The symptoms of unresponsiveness, rigidity, and sweating are indicative of possible neuroleptic malignant syndrome (NMS), a serious and potentially life-threatening reaction to antipsychotic medications such as risperidone. NMS is characterized by muscle rigidity, altered mental status, autonomic dysregulation (which includes symptoms like sweating), and fever.

In cases of NMS, prompt recognition and management are crucial. This includes discontinuing the offending medication, as continuing its use could exacerbate the patient's condition and lead to further complications. While seeking other interventions, such as supportive measures or medications to manage symptoms, is essential, the immediate priority is to remove the trigger, which in this case is the risperidone.

Starting a new antidepressant, increasing the lithium dosage, or ordering a CT scan of the brain do not address the immediate risk posed by the potential NMS. These actions may delay necessary treatment and could worsen the patient's situation. Thus, discontinuing risperidone is the most appropriate and urgent step in managing this patient's condition.