Arachnoid cysts are of the organic causes of the first episode of psychosis. In most cases they are diagnosed by accident. The coexistence of arachnoid cysts with first episode psychosis had not been closely covered in the literature. A possible link between arachnoid cysts and psychotic symptoms has been given an increased interest and raised questions about the etiopathogenesis and the therapeutic approach. We present four patients with first episode psychosis, who were also negative to other clinical evaluations including thyroid functioning. Their psychotic symptoms were suspected to be induced by the arachnoid cyst and it was controlled by moderate-dose antipsychotic administration.
Case 1 is a 21-old male patient, who was admitted due to mystic delusions, wish to die in the way of Jihad, plan to go to Syria to struggle against the enemies of Islam and aggressiveness towards his family. He let his beard grow for 6 months. An arachnoid cyst was found in the right side of axial plan in retrocerebellar region about 4.2X2.1 cm in size on his. Aripiprazole 30 mg/day PO and zuclopentixol decanoate 200 mg IM(per 10 days) were administered.
Case 2 is a 36- year- old male patient, who was admitted due to delusions of persecution and reference about his family and aggressiveness towards them. An arachnoid cyst was found in the anterior pole of right temporal lobe about 2.5x4.5 cm in size on his magnetic resonance image. We started paliperidone palmitate 150 mg IM (weekly) and quetiapine 300 mg PO. bid.
Case3 is a 52- year- old male patient, who was presented with intense delusion of jealousy about his wife. An arachnoid cyst was found in the posterior of the midline of the posterior cranial fossa about 3x4.5 cm in size on his magnetic resonance image. We administered amisulpride 400 mg/day PO, quetiapine 200 mg PO tid and biperidene 1 mg/day PO.
Case 4 is a 25 –year-oldmale patient with mystical and persecutory delusions for two years. And moderately controlled by risperidone 8 mg/day, Biperidene 2 mg /day, Quetiapine 100 mg /day and ECT was planned.. An arachnoid cyst was found in the posterior fossa of right side of cerebellar vermis about 3x4 cm size on his magnetic resonance image. All the cases revealed no pathologicaland neurological signs. The MRI of the cases were consulted with neurosurgery, no surgical intervention was needed. In this report, we present the clinical manifestations and treatment of the cases of first episode psychosis associated with arachnoid cyst. It is difficult to be absolutely certain whether the lesion had inşuence on the patient’s psychiatric symptoms or not. However, given the anatomical and neuropsychological changes, one cannot exclude the possibility that the lesion played a significant role in this psychiatric presentation.