neuropsychiatric manifestations are included : p0 eripheral neuropathy , myeloneuropathy , cerebellar ataxia , optic atrophy , mood disorders , psychosis , personality changes , loss of memory , depression , dementia , confusion and more rarely reversible manic and schizoferniform status and obsessive compulsive disorder ( ocd).[18 ] psychiatric manifestations of b12 deficiency seldom precede anemia.[68 ] we present a case of b12 deficiency in which ocd precedes anemia .
a 29-year - old female came with anxiety and history of ocd since 11 years ago .
general blood chemistries including thyroid function tests , liver function tests , renal function tests , cbc diff , hemoglobin level and iron profile had been performed 5 months ago and all were in normal ranges [ table 1 ] , but further investigations in recent visit showed mild anemia ( hb=11.8 g / dl , mcv=89 fl ) and markedly diminished serum cobalamine level to < 30 pg / ml and also iron deficiency with significant decreased ferritin level to 1.28 ng / ml [ table 2 ] .
laboratory findings of first visit laboratory findings of the recent visit the association between b12 deficiency and iron deficiency in this case was our explanation to her normocytic anemia .
diagnosis of b12 deficiency with ocd manifestation and concurrent iron deficiency was made and parenteral b12 and oral iron replacement therapy initiated .
in this 29-year - old female , ocd was the early manifestation of b12 deficiency .
although , it was rarely reported , but psychiatric and mood disorders may be the first manifestation of b12 deficiency and precede anemia.[68 ] we recommend checking serum b12 and folate level in any case with psychiatric disorder such as ocd , even in the absence of anemia and other hematologic manifestations of b12 and/or folate deficiencies .
b12 replacement therapy can resolve symptoms of psychiatric disorders in patients with b12 deficiency.literature review shows that patients with ocd have dysregulation in serotoninergic system and efficacy of serotonin reuptake inhibitors ( sris ) in the treatment of ocd was demonstrated.[912 ] neurotransmitters ( dopamine , serotonin and melatonin ) are necessary for a normal balanced mood , emotions and also sleeping .
folic acid and vitamin b12 act as cofactors in synthesis of neurotransmitters such as serotonin and norepinephrine .
although it is rare but psychiatric manifestations of b12 deficiency may precede anemia as we saw in this case .
 b12 acts as a cofactor in synthesis of neurotransmitters such as serotonin and dopamine , thus b12 deficiency affects mood , emotions and sleeping and can lead to psychiatric disorders . 
 psychiatric manifestations of b12 deficiency are varied . 
 they seldom precede anemia . 
 we want to present a case of b12 deficiency which was presented with obsessive compulsive disorder . 
INTRODUCTION
CASE REPORT
RESULT
DISCUSSION