Is lying considered a sin if one is compelled to do so due to a speech impediment (stammering) that only appears when speaking with people?

Inability to speak or speech impediment is a known medical symptom within the symptoms of social phobia (social anxiety disorder). Its treatment consists of cognitive-behavioral therapy, relaxation therapy (breathing exercises), and pharmacotherapy (antidepressants under medical supervision). According to Islamic law, one must seek treatment and avoid lying, which may result from this disorder.