¹Chang Gung Memorial Hospital, Keelung, Psychiatry, Keelung City, Taiwan

Background: Obsessive-compulsive disorder (OCD) is classically characterized by intrusive obsessions and anxiety-driven compulsions mediated by cortico-striato-thalamo-cortical (CSTC) circuit dysfunction. Although neuropsychiatric sequelae are common after stroke, compulsive or OCD-like phenomena remain rare and under-recognized. Post-stroke compulsive behaviors without accompanying obsessions represent a poorly defined neuropsychiatric entity.

Aims & Objectives: To describe a rare case of post-stroke compulsive-like motor behaviors occurring without obsessions and demonstrating favorable response to selective serotonin reuptake inhibitor (SSRI) treatment, and to explore its neuroanatomical and mechanistic implications.

Method: A 58-year-old man with vascular risk factors presented with repetitive, involuntary yet partially suppressible motor behaviors following extensive ischemic stroke involving the left internal carotid artery and basilar artery territories. Neuroimaging, laboratory evaluations, neurological examinations, and longitudinal psychiatric assessments were reviewed. Differential diagnoses included tic disorder, stereotypy, punding, extrapyramidal syndromes, and metabolic etiologies. Empirical pharmacological interventions and therapeutic responses were documented.

Results: During subacute recovery, the patient developed persistent repetitive “air biking,” sit-up-like, and running-like lower-limb movements lasting minutes to hours daily. The behaviors were partially suppressible, preceded by an internal urge, and occurred without intrusive obsessive thoughts or anxiety relief after execution. Extensive medical evaluation showed no metabolic or movement disorder etiology. Prior trials of benzodiazepines, dopamine-modulating agents, anticholinergics, and antipsychotics were ineffective. Sertraline (SSRI) was initiated at 40 mg/day and titrated to 60 mg/day, leading to marked reduction in movement intensity and frequency over four weeks, with sustained stabilization during follow-up.

Discussion & Conclusions: Discussion: This presentation illustrates a rare motor-dominant compulsive phenotype occurring in the absence of obsessions after large-territory ischemic stroke. The combination of anterior and posterior circulation involvement likely disrupted multiple subcortical CSTC nodes, including basal ganglia, thalamus, and brainstem structures. Phenomenologically, the behavior overlapped with compulsions, punding, and complex tics; however, the presence of internal urge, partial suppressibility, and robust SSRI response favored classification within the obsessive-compulsive spectrum. These findings support a model of serotonergic modulation acting on structurally compromised CSTC circuitry to regulate compulsive motor output.
Conclusion: Post-stroke compulsive-like motor behaviors without obsessions represent a rare but clinically significant neuropsychiatric syndrome arising from CSTC network disruption. This case demonstrates that SSRIs may remain effective even when compulsive phenomena are structurally mediated. Early recognition and targeted serotonergic treatment may substantially reduce morbidity and functional impairment in similar cases.