Behçet's Disease(BD) is a primary vasculitis with wide variety of symptoms, in which psychiatric disorders as Bipolar Affective Disorder(BPD) are seen. In such cases; as in all comorbidities, the importance of preferring appropriate treatment is emphasized.

We present a case of hematologic toxicity associated with a valproate level of 116 mg/l in of BPD and BD comorbidity.

The 38 years old male patient, who was diagnosed as BPD 10 years ago and BD 3 years ago, was hospitalized for mixed episode with psychotic features. His routine laboratory parameters were in normal ranges. Olanzapine 10mg/d and valproate 500mg/d were started and Valprote was titrated up to 1000 mg/d. At the 8th day of medication he complained of fatigue and somnolence. By the following 6 days a decrease in the hematologic values as: haemoglobin:15,0/11,4g/dl, hematocrit:%42/32, platelets:334000/202000 microg/ml was noticed. He had no active symptoms of BD. The liver enzymes were moderately high and because of the hepatoxicity with valproate was reported in previous studies, Valprote was stopped and Olanzapine was continued. The hematological and biochemical parameters normalized in two weeks.

The decrease of hematological parameters could not be explained by BD itself or any other organic pathology and normalized after cessation of valproate. Thus a hematotoxicty associated by valproate was considered.

Although the effects of the comorbidity of BPD-BD to hemototoxicity are not clear exactly, this case underlies the importance of careful monitoring the Valprote levels and associated parameters in BPD particularly if comorbidity is present.