isotretinoin is the 13-cis isomer of retinoic acid , the active form of vitamin a. isotretinoin works in acne by reducing sebaceous gland size , inhibiting the formation of new comedones , reducing growth of propionibacterium acnes , and decreasing inflammation . improvement usually takes at least 2 months , and treatment needs to be continued for at least 4 months . although it is indicated only for severe , treatment - resistant cystic or nodular acne , in practice , it is being increasingly prescribed even for mild or moderately severe acne . in the us , isotretinoin carries a so - called  black box  prescription warning of potential psychiatric side - effects including depression , suicide , and psychosis . it ranks in the top 10 drugs with respect to the number of reports of depression and suicide attempts . between 1982 and 2000 , 37 patients on isotretinoin committed suicide , while 110 patients needed inpatient treatment for depression . while depression has been the most common psychiatric side - effect , psychosis has been occasionally documented . in this report , i present a patient who developed acute psychosis after being prescribed isotretinoin for acne . m was a 27-year - old single male , who had been working as an engineer in germany for 15 months . he had returned suddenly from germany the previous day , as he was convinced that his life was under threat from his work colleagues . when asked why he was being targeted , he said that he had developed a software tool at work recently , which because of its effectiveness was able to do the job of several people ; consequently , some of his colleagues were angry with him as they were at risk of losing their jobs . he believed that his drinks and food in germany were being contaminated to harm him . he was convinced that his mobile phone calls were hacked , his internet activity was being monitored , and that he was being followed . he had written to his company management about his perceived persecution , and he had even lodged a complaint with the local german police who visited him at home to reassure him that he was safe . even though he felt safer in chennai than in germany , he was concerned about potential harm to himself and his family from his german colleagues . he reported that he was started on isotretinoin by a dermatologist in germany for acne ( which by his account and on appearance did not seem particularly severe ) about 2 weeks previously . he reported no history of any major medical illnesses and was not on any regular medication apart from the recently started isotretinoin . he was born of a full - term normal delivery and his mother said that his developmental milestones were normal . he held a master 's degree in engineering , and had work experience for 4 years in an indian company before going to germany . he had a slightly blunted affect , although he was able to smile at times . on testing his cognition , he was oriented in time and place , his immediate and delayed recall were normal , his concentration ( serial 7s test ) was preserved and he was able to interpret a proverb correctly . with respect to insight , he did not think he had a psychiatric problem and was more concerned about potential harm to his physical health due to deliberate nevertheless , he was willing to cooperate with the plan i suggested . a provisional diagnosis of an acute psychotic episode ( international classification of diseases-10 category f23.3   other predominantly delusional psychotic disorders  ) was made , on the basis of acute onset of delusions ( mainly of a persecutory nature ) within a period of < 2 weeks . isotretinoin was considered the likely precipitant as the onset of the symptoms followed its initiation . although a functional origin of symptoms was possible ( i.e. first episode of a functional mental illness like schizophrenia ) , absence of any prodromal symptoms , previous psychiatric history , or family psychiatric history made this unlikely . in addition he was prescribed clonazepam 0.25 mg twice a day and zolpidem 5 mg at night . his sleep had improved , the  heaviness  in the head was much less , he no longer believed he or his family were under threat , and he was even open to the possibility of returning to germany ( an option he was vehemently against just 3 days previously ! ) . his investigations ( complete blood count , thyroid function test , liver function test , glucose , cholesterol , creatinine , and electrocardiography ) were within normal limits . he was advised to continue risperidone 1 mg at night and zolpidem 5 mg at night . m was reviewed again 4 days later ( 7 days after his first presentation ) . he felt he was fully back to his normal self , and this was corroborated by his mother . he was keen to return to germany as soon as possible , and i provided him a certificate of fitness to return to work . be living on his own in germany , i advised him to take risperidone 1 mg at night for a further 3 months , mainly as a precautionary measure . he continues to remain well 11 months after his original presentation ( 8 months without medication ) . the naranjo adverse drug reaction probability scale is sometimes helpful in determining whether a particular side - effect is due to a specific medication . the aggregate score from 10 items falls under four possible categories :  doubtful  if the score is 0 , possible  if 1 - 4 ,  probable  if 5 - 8 and  definite  if the score is 9 or more . in this patient , this is one more case highlighting the potential psychiatric consequences of a medication used to treat a physical condition . isotretinoin has been in the international market since 1982 and is considered superior to other anti - acne treatments ( a position similar to that of clozapine among antipsychotics ) . however , considering its wide range of side - effects , it is officially recommended only for recalcitrant severe acne ( similar to clozapine being given only for treatment - resistant schizophrenia ) . due to its effectiveness , there has been an increasing tendency for isotretinoin to be prescribed even for less severe forms of acne ( as was the case in this patient ) . as a result , the exact mechanisms by which isotretinoin causes psychiatric side - effects are not known . while sufficient levels of vitamin a and its derivate , the retinoids , are important for central nervous system functioning , excess vitamin a can be harmful . aetiology of psychosis due to isotretinoin is poorly understood and there do not seem to be any hypotheses yet . there have been only a handful of previous reports of psychosis : a case series of five cases of manic psychosis and three individual case reports of affective psychosis . those cases have been mainly in those with a past history or family history of mental illness . the patient presented here had no prominent affective symptoms , and neither did he have a past psychiatric or family psychiatric history . the duration between initiation of isotretinoin and onset of psychotic symptoms was only 5 days in this patient , while in the previous case reports it has varied from 2 weeks to up to 11 months . this case reminds us of the importance of taking a full history , including medical history , during the initial assessment . if the use of isotretinoin had not been elicited in history , the patient would have got a label of a functional psychotic illness ( such as schizophrenia ) , would probably have been prescribed antipsychotics for much longer , and would have had to live with the stigma of being labelled mentally ill . furthermore , isotretinoin may have been continued by the patient and it would have interfered with the effectiveness of the antipsychotic , necessitating higher doses of the antipsychotic . the general principles of treatment in drug - induced ( including prescribed medication ) psychosis should be : stop the offending drug , prescribe lowest effective dose of antipsychotic , and adjunct sedative / hypnotic for the shortest possible time . these simple strategies helped the patient get better very quickly and return to his previous level of functioning . psychiatrists in addition to being aware of physical side - effects of the psychotropic drugs they prescribe ( such as extra - pyramidal side - effects and metabolic syndrome ) should also consider the possibility that typical psychiatric symptoms can be caused by medication prescribed for physical disorders .
isotretinoin is used for the treatment of severe acne . 
 psychiatric side - effects , particularly depression , have been well - documented . 
 this dramatic case report is about a young male patient who developed acute psychosis within a few days of starting isotretinoin . due to his persecutory delusions , 
 the patient , who was an indian engineer working in germany , decided to immediately return to india fearing for his life in germany . 
 careful history taking established the cause of the psychosis . 
 isotretinoin was stopped ; patient showed rapid improvement , within a week , on a low dose of risperidone . 
 risperidone was continued as a precaution for 3 months . after a further 8 months 
 , the patient remains well without any psychotropic medication .