it is not synthesized in human body and supplied exclusively in non - vegetarian diet .
psychiatric disturbances include apathy , depression , dementia , delirium , delusions , hallucinations , irritability , incoherent speech , and catatonia are commonly reported in adults / elderly . till date , the psychiatric presentations of cobalamin deficiency are reported in four children .
second , oral vitamin - b12 monotherapy showed dramatic improvement in psychosis , but relapsed a year later after stopping ; however , author did not mention serum vit - b12 level or other manifestations .
third , inadequate dietary intake of vitamin b12 and folate presented as neuropsychiatric changes and megaloblastic anaemia .
last , a case of psychotic disorder and thrombotic manifestations of vitamin b12 and folate deficiency . however , there is no report of vegetarian pediatric case presenting solely as psychosis due to dietary deficiency .
authors report a first case of dietary deficiency of cobalamin in lacto - vegetarian adolescent presenting solely as schizoaffective disorder without hematological / neurological manifestations .
a 13-year - old lacto - vegetarian class viii boy was presented from lower socioeconomic status with nil significant family and personal history .
no past history of gastrointestinal pathology , surgeries , or use of alcohol or proton - pump blockers .
patient admitted with 1 week history of mutism , rigidity , immobility , staring look , disturbed sleep , ideas of worthlessness and hopelessness , aimless wandering , guilt , and suicidal ideas . physical examination ( pe ) found no abnormality . on mental status examination ( mse ) , patient had partial mutism , manneristic posture , depressed mood , paranoid delusions , thought echo / broadcast , running commentary , and command hallucinations .
complete blood count with peripheral blood smear , blood sugar , renal / liver function test , serum iron , total iron binding capacity , urinary iron binding capacity , transferring , and transferrin saturation were normal .
he responded quickly with lorazepam-6 mg / day ( stopped third day ) , olanzapine-15 mg / day and sertraline-50 mg / day , and discharged in 5 days .
subsequently patient was asymptomatic , but had functional disability for which aripiprazole 15 mg / day was added and followed up for the next 2 months .
then patient relapsed despite good adherence with 1 week history of suspiciousness , hearing voices , over - talkativeness , over - cheerfulness , inflated self - esteem , decreased need for sleep , increased appetite , increased pleasurable activities , and disruptive socio - education .
mse revealed inflated self - esteem , over - familiarity , spontaneous over - productive speech , increased psycho - motor activity , elated affect , flight of ideas , thought echo and broadcasting , delusions of persecution and reference , command and commentary second person hallucinations , impaired judgment , and absent insight .
sertraline stopped and divalproate sodium-500 mg / day added along with olanzapine-15 mg / day and aripiprazole-15 mg / day .
divalproate increased to 1 gm and lithium carbonate 600 mg and haloperidol-10 mg were added .
two days later , patient was re - admitted for worsening of symptoms for evaluation of organicity .
no abnormality in magnetic resonance imaging of brain , thyroid function test , and gastric mucosal biopsy by upper gastrointestinal endoscopy was reported .
serum cobalamin level was 112 ng / ml ( normal range : 180 to 914 ng / ml ) while serum folate was normal .
patient started on alternate days 1 ml intramuscular injection vitcofol ( vitamin b12 = 500 mcg , folate = 15 mg andniacinamide = 200 mg per ml ) for six doses , then 2 ml monthly .
patient became asymptomatic soon after second dose of cobalamin and discharged in 1 week . during followups ,
normal serum cobalamin level was maintained and psychiatric medications tapered and stopped on the 52 day of vitcofol .
atypical presentation of case consists of acute onset , fluctuating course of psychotic spectrum initially with catatonia , depressive symptoms , first rank symptoms , ( frs ) , and later as mania , frs , and relapsed soon on medications .
patient reached quickly and maintained the premorbid level in the short - term follow - up with only cobalamin supplementation .
dietary deficiency of cobalamin associated with psychosis is significant in developing country like india for two reasons .
first , the high prevalence of dietary deficiency of cobalaminin indian children , and second , course and prognosis with supplementation is better .
this emphasizes the importance of diet history and performing serum cobalamin level as a routine investigation in first episode , atypical presentation , and treatment resistant cases , especially in vegetarian .
early diagnosis and treatment of cobalamin deficiency in neuropsychiatry is recommended for following reasons : first , better prognosis is expected if treated in window period to avoid irreversible neuronal injury .
second , to avoid treatment resistance and last , finding that high vitamin b12 level is associated with better treatment outcomes .
methylene - tetrahydrofolate reductase , an enzyme of cobalamin metabolism , is involved in metabolism of tetrahydrobiopterin and latter is required for synthesis of dopamine and serotonin .
short - term followup is a limitation , but , rapid disappearance of florid psychopathology and maintaining pre - morbid level solely on cobalamin supplementation is vital .
early diagnosis and treatment of cobalamin deficiency during narrow window period is an opportunity to revert pathophysiology .
this highlights the importance of diet history and serum cobalamin level in atypical psychiatric presentations .
 cobalamin is an important nutrient . 
 it is not synthesized in human body and supplied only in nonvegetarian diet . 
 its deficiency reported with range of psychiatric disorders . 
 only four pediatric cases have been reported as psychiatric disorders . 
 authors report a case of dietary deficiency of cobalamin presenting solely as schizoaffective disorder without hematological / neurological manifestations . 
 early diagnosis and treatment of cobalamin deficiency is an opportunity to reverse pathophysiology . 
 this case highlights the importance of diet history and serum cobalamin level in atypical psychiatric presentations . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION