Symptoms markedly worsened; Psychosis; Anxious; Being able to talk with dead people, hearing people drumming outside his house' and the constant voice of a co-worker whom he believed to be a paramour- it was later confirmed that there was no romantic relationship/ auditory hallucinations; Superficial and grandiose/ grandiose delusions of becoming clairvoyant; Grandiose delusions of becoming clairvoyant; Erotomaniac delusions; poor insight; Erythrocyte sedimentation rate increased; Leukocytosis; focus of susceptibility in the right lateral thalamus; This literature-non-study case was reported in a literature article and describes the occurrence of CONDITION AGGRAVATED (Symptoms markedly worsened), PSYCHOTIC DISORDER (Psychosis), ANXIETY (Anxious), HALLUCINATION, AUDITORY (Being able to talk with dead people, hearing people drumming outside his house' and the constant voice of a co-worker whom he believed to be a paramour- it was later confirmed that there was no romantic relationship/ auditory hallucinations), DELUSION OF GRANDEUR (Superficial and grandiose/ grandiose delusions of becoming clairvoyant), DELUSIONAL DISORDER, PERSECUTORY TYPE (Grandiose delusions of becoming clairvoyant), DELUSIONAL DISORDER, EROTOMANIC TYPE (Erotomaniac delusions), ANOSOGNOSIA (poor insight), RED BLOOD CELL SEDIMENTATION RATE INCREASED (Erythrocyte sedimentation rate increased), LEUKOCYTOSIS (Leukocytosis) and MAGNETIC RESONANCE IMAGING HEAD ABNORMAL (focus of susceptibility in the right lateral thalamus) in a 31-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.   LITERATURE REFERENCE:     Concurrent medical conditions included Schizotypal personality (strongly associated with the development of schizophrenia).   On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date, the patient experienced CONDITION AGGRAVATED (Symptoms markedly worsened) (seriousness criterion hospitalization), PSYCHOTIC DISORDER (Psychosis) (seriousness criterion hospitalization), ANXIETY (Anxious) (seriousness criterion hospitalization), HALLUCINATION, AUDITORY (Being able to talk with dead people, hearing people drumming outside his house' and the constant voice of a co-worker whom he believed to be a paramour- it was later confirmed that there was no romantic relationship/ auditory hallucinations) (seriousness criteria hospitalization and medically significant), DELUSION OF GRANDEUR (Superficial and grandiose/ grandiose delusions of becoming clairvoyant) (seriousness criterion hospitalization), DELUSIONAL DISORDER, PERSECUTORY TYPE (Grandiose delusions of becoming clairvoyant) (seriousness criterion hospitalization), DELUSIONAL DISORDER, EROTOMANIC TYPE (Erotomaniac delusions) (seriousness criterion hospitalization), ANOSOGNOSIA (poor insight) (seriousness criterion hospitalization), RED BLOOD CELL SEDIMENTATION RATE INCREASED (Erythrocyte sedimentation rate increased) (seriousness criterion hospitalization), LEUKOCYTOSIS (Leukocytosis) (seriousness criterion hospitalization) and MAGNETIC RESONANCE IMAGING HEAD ABNORMAL (focus of susceptibility in the right lateral thalamus) (seriousness criterion hospitalization). The patient was treated with RISPERIDONE (oral) for Adverse event, at a dose of .5 milligram once a day; RISPERIDONE (oral) for Adverse event, at a dose of .5 milligram once a day and RISPERIDONE (oral) for Adverse event, at a dose of 1 milligram once a day. At the time of the report, CONDITION AGGRAVATED (Symptoms markedly worsened), PSYCHOTIC DISORDER (Psychosis), ANXIETY (Anxious), ANOSOGNOSIA (poor insight), RED BLOOD CELL SEDIMENTATION RATE INCREASED (Erythrocyte sedimentation rate increased), LEUKOCYTOSIS (Leukocytosis) and MAGNETIC RESONANCE IMAGING HEAD ABNORMAL (focus of susceptibility in the right lateral thalamus) outcome was unknown and HALLUCINATION, AUDITORY (Being able to talk with dead people, hearing people drumming outside his house' and the constant voice of a co-worker whom he believed to be a paramour- it was later confirmed that there was no romantic relationship/ auditory hallucinations), DELUSION OF GRANDEUR (Superficial and grandiose/ grandiose delusions of becoming clairvoyant), DELUSIONAL DISORDER, PERSECUTORY TYPE (Grandiose delusions of becoming clairvoyant) and DELUSIONAL DISORDER, EROTOMANIC TYPE (Erotomaniac delusions) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Blood test: normal (normal) normal. On an unknown date, Chest X-ray: normal (normal) normal. On an unknown date, Computerised tomogram head: abnormal (abnormal) showed hyperintensities throughout the subcortical and periventricular white matter.. On an unknown date, Electroencephalogram: negative (Negative) Negative (after the patient was admitted to the neurology service).. On an unknown date, Full blood count: abnormal (abnormal) moderate leukocytosis with left shift.. On an unknown date, Magnetic resonance imaging: abnormal (abnormal) revealed focus of FLAIR hyperintensity in the left peritrigonal white matter, with multiple nonspecific punctate hyperintensities throughout the subcortical and periventricular white matter and focus of susceptibility in the right lateral thalamus.. On an unknown date, Red blood cell sedimentation rate: 48 mm/h (Inconclusive) 48 mm/h. On an unknown date, SARS-CoV-2 test: negative (Negative) Negative. On an unknown date, Urine analysis: normal (normal) normal. On an unknown date, Vital signs measurement: normal (normal) normal.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered CONDITION AGGRAVATED (Symptoms markedly worsened), PSYCHOTIC DISORDER (Psychosis), ANXIETY (Anxious), HALLUCINATION, AUDITORY (Being able to talk with dead people, hearing people drumming outside his house' and the constant voice of a co-worker whom he believed to be a paramour- it was later confirmed that there was no romantic relationship/ auditory hallucinations), DELUSION OF GRANDEUR (Superficial and grandiose/ grandiose delusions of becoming clairvoyant), DELUSIONAL DISORDER, PERSECUTORY TYPE (Grandiose delusions of becoming clairvoyant), DELUSIONAL DISORDER, EROTOMANIC TYPE (Erotomaniac delusions), ANOSOGNOSIA (poor insight), RED BLOOD CELL SEDIMENTATION RATE INCREASED (Erythrocyte sedimentation rate increased), LEUKOCYTOSIS (Leukocytosis) and MAGNETIC RESONANCE IMAGING HEAD ABNORMAL (focus of susceptibility in the right lateral thalamus) to be possibly related.    Concomitant medications were not provided.  After the electroencephalogram (EEG) results came negative, the patient refused a lumbar puncture. The following day the patient was wandering the unit talking to himself, stating that the EEG machine was communicating with him'. Risperidone treatment was started and the dose was increased and was placed on one-to-one observation. The next day, the patient was transferred to the psychiatric ward and was engaged in milieu treatment, and the hallucinations and delusions resolved after two days.  The patient was discharged on the same medication regime five days later, with good insight about the symptoms. One week after discharge the patient was taking medication, asymptomatic and back to work.  Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.  However, patient´s history of Schizotypal personality is a confounder for the events. More information regarding other findings and events (abnormal MRI, lab abnormalities interpretation) has been requested.   This case was linked to MOD-2021-290513 (Patient Link).; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.  However, patient´s history of Schizotypal personality is a confounder for the events. More information regarding other findings and events (abnormal MRI, lab abnormalities interpretation) has been requested.