The classical clinical picture of antiphospholipid antibody syndrome (APS) is characterized by venous and arterial thrombosis, fetal losses and thrombocytopenia in the presence of anticardiolipin antibodies and/or lupus anticoagulant. APS can occur either as a primary disorder or secondary to a connective tissue disease, most frequently systemic lupus erythematosus. Central nervous system involvement is one of the most prominent clinical manifestations of APS, and includes thrombotic events, psychiatric features and a variety of other non-thrombotic neurological syndromes. We present a 9-year-old Saudi girl who developed psychotic illness without thrombotic manifestations. Autoantibodies against cardiolipin were persistent and strongly positive while antinuclear antibodies and antibodies against double-stranded DNA was absent. Her brain computed tomography, magnetic resonance imaging, magnetic resonance arteriography and magnetic resonance venography all were normal. There was no evidence of infection, drug intake or connective tissue disorders, So a diagnosis of primary APS was likely. Starting on antipsychotics only was unsatisfactory and marked improvement occurred after combined treatment with antidepressants (imipramine 10 mg and risperdal 0.2 mg, both once daily), small-dose aspirin (100 mg) and hydroycloroquine (100 mg) both once daily. Unfortunately aspirin was stopped by the family and 5 months later she developed right axillary vein thrombosis. This case presented psychotic illness. Investigations revealed the presence of anticardiolipin antibodies without a thromboembolic picture, mimicking Hughes syndrome but not fulfilling the criteria needed for the diagnosis. Thus, psychosis should be appreciated as a presenting symptom for primary APS and combined treatment with antipsychotics, aspirin and antimalarials is recommended.