Abstract: BACKGROUND: Shared Delusional Disorder is not uncommon and has been included in formal diagnostic classification systems. However, it is not frequently diagnosed. This is a case of a 21 year old female, unmarried, who presented to our OPD with prominent psychotic symptoms, particularly a fixed belief that she was being followed by someone for the last six years. Her elder sister, who was close to her emotionally also developed persecutory delusion of similar content within one year of its onset in the younger sister. Thus when they first presented to the OPD, both sisters had similar type of psychotic presentation. After separation of both sisters, psychotic symptoms improved in elder sister within one month. CONCLUSION: Shared Delusional disorder is not uncommon. The risk of induced delusion is more among those who have high emotional bonding and it disappears following separation of each other. So it is necessary to evaluate the family member of individuals suffering from psychiatric disorder to rule out Induced delusional disorders. The conceptual issues of the problem are also discussed.Abstract: BACKGROUND: Shared Delusional Disorder is not uncommon and has been included in formal diagnostic classification systems. However, it is not frequently diagnosed. This is a case of a 21 year old female, unmarried, who presented to our OPD with prominent psychotic symptoms, particularly a fixed belief that she was being followed by someone for the l...Show More