This 76-year-old, right-handed woman with no significant medical history presented to Yamashiro Public Hospital with the acute onset of headache and nausea while karaoke singing. Upon arrival to the hospital, she was alert and no neurological deficit was recognized. A noncontrast head computed tomography (CT) demonstrated SAH mainly in the right sylvian fissure (Fig. 1A), and subsequent intraarterial digital subtraction angiography (DSA) confirmed the presence of a 6.5-mm-diameter, saccular aneurysm at the posterior communicating segment of the right internal carotid artery (Fig. 1B). The patient underwent a frontotemporal craniotomy on day 2 and clip ligation of the aneurysm was performed. Postoperative course was uneventful as her Glasgow Coma Scale (GCS) score immediately after the operation was 15 and had no neurological complications, and had full oral intake until day 6 when she developed loss of consciousness and left hemiparesis (GCS score of 11). Intraarterial DSA revealed severe diffuse vasospasm in the right middle cerebral artery and right anterior cerebral artery (Fig. 2A). Despite several treatments, cerebral infarction in the right and prefrontal cortex and corona radiata resulted (Fig. 2B), and she was afflicted by persistent disturbance of consciousness. About 6 months after the onset of SAH, she gradually recovered from conscious disturbance and became alert and fully independent, with her GCS 15, but at the same time she recognized involuntary bouts of laughter that was not related to her emotion, was inappropriate to the situation, and was unable to be controlled by herself. She reported that during the laughter she was fully conscious and felt embarrassed about the laughter and that no inappropriate crying was coincide. To evaluate the pathogenesis of her pathological laughing, repeat magnetic resonance (MR) images were performed but no additional lesion other than scar of cerebral infarction could be found. She hesitated to have social life as before because she feared the outburst of laughing during inappropriate situation. The pathological laughing and crying scale (PLACS) score at that time was 18 that is above the recommended cutoff score of 13 to identify patients with pathological laughing. The symptoms lasted for 4 years until treatment with sertraline at a daily dose of 50 mg commenced. She responded well with respect to her presenting symptoms, including her involuntary laughing, which resolved over 6 weeks as the PLACS scale decreased to 7.