Systemic Lupus Erythematosus (SLE) can affect central nervous system (CNS), leading to neurological and/or psychiatric disorders. The use of corticosteroids for the management of SLE may induce psychiatric disorders.

Differential diagnosis of the origin of psychosis in patients with SLE (CNS lupus vs. induced by corticosteroid therapy).

A 22 year old female patient presented asthenia, oral bleeding, epistaxis, metrorrhagia, bicytopenia, hypoalbuminemia, low complement, with anti-DNA>300, ANA, IgG Anticardiolipin, Anti-Sm, anti-RNP, anti-Ro, Anti-La and Anti-Histone positive.

A diagnosis of SLE was made. She presented also diffuse grade IV nephritis. There were administered 3 iv 6-methylprednisolone pulse therapies (750mg/day) with a cycle of cyclophosphamide. Subsequently she continued with oral prednisone 60mg/day. Four days after the end of the pulses, the patient developed anxiety, suspicion, injury delusions, auditory hallucinations and behavioral disinhibition. A MRI was normal. Risperidone was started up to 6mg/day and oral prednisone was tapered. After a progressive improvement she was discharged.

Corticosteroids induce psychiatric disorders in 3–10% of patients. Low levels of complement, hypoalbuminemia and a positive ratio (≥9) of albumin in CSF x10³/serum albumin are indicators of blood brain barrier damage and psychosis induced by corticosteroids. The presence of ac Antiribosoma P, ac antineuronals, MRI or EEG abnormals suggest the diagnosis of CNS lupus (lupus psychosis)

Differential diagnosis between lupus psychosis vs. psychosis induced by corticosteroids is complicated. In case of doubt, some authors advocate increasing the dose of steroids and awaiting a clinical response. Others advocate rapid tapering and stopping steroids.