Dissociative stupor is a rare psychiatric condition, included in the Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) among Other Specified Dissociative Disorders, as an acute dissociative reaction to a stressful event. Like other acute pathological dissociative presentations, it is primarily related to traumatic experiences. Aim. This article aims at presenting the case of dissociative stupor in a 21-year-old male who presented firstly with mixed symptoms of tonic seizures and catatonia. Method. Before the present admission, the patient had two previous emergency department presentations, upon which he presented altered consciousness, muscular rigidity, unresponsiveness to external stimuli, alternated with episodes of psychomotor agitation and visual hallucinations, symptoms partially remitted after the administration of propofol, levetiracetam and solumedrol. During the presentation, the patient’s mother revealed that the patient may have seen the dead body of his grandfather, with whom he had a previously close relationship, and found out in this manner that he passed away during the previous night. Urinary tox-screen was positive for tetrahydrocannabinol (THC). Also, complete blood count (CBD), basic metabolic panel (BMP), cerebrospinal fluid (CSF) analysis, cerebral magnetic resonance imaging (MRI), both native and angiographic sequence, and electroencephalogram (EEG) were performed, with results within normal range. The treatment with selective serotonin reuptake inhibitors (SSRI’s; sertraline) and second-generation antipsychotics (SGA; olanzapine) was initiated. Discussion. From a psychiatric point of view, the patient needs to be reevaluated periodically regarding the psychopharmacologic therapy; also, cognitive-behavioral therapy (CBT) or hypnosis may be an option in this case. Conclusions. The diagnosis and therapeutic management of dissociative stupor represents a real challenge due to the need of excluding other psychiatric or somatic conditions and the fact that there are no available data regarding the psychopharmacological treatment. However, there is much ongoing research in the neurobiology of trauma-related altered states of consciousness and the promising results of them are the basis of future psychopharmacological strategies.