A delusion is a belief held by the patient, which is false and held firmly by him/her despite its contrary and not shared by their family members or society.

1. Delusion of persecution: A person believed that his food was poisoned by his family members and refused to eat, despite repeated reassurance.
2. Delusion of jealously( infidelity): A chronic alcoholic believed that his wife was unfaithful and used to harm her even though all his relatives explained that it was false.
3. Delusion of reference: A 30-year-old lady believed that all her neighbourhood men and women talked ill of her and repeatedly quarrel with them.
4. Delusion of disease (somatic delusion): A 70-year-old male person believed that he has stomach cancer and had gone to various physicians and surgeons for its treatment, even though all examinations and investigations were proved negative.
5. Delusion of guilt or sin: A 40year old lady believed that she deserves punishment by death as she had missed going to the temple last weekend.
6. Bizarre (scientifically not possible) delusions: The 17-year-old student believed that cosmic rays are sent by a satellite from Jupiter, and that is controlling all his actions, including his speech and his movement. B. A 25year old telephone operator believed that all the people in the city knew all his thoughts through telephone lines as a transmitter is fixed in his brain.
7. Delusion of grandeur: A 25year old farmer believed that he was a landlord and owned thousands of acres of land, even though he was a coolie in others field.

   The above examples have few things in common

   -They are all false belief, believed by the patient only.

   -They persist firmly despite giving the proof that it is wrong.

   -The belief is not shared by other members of his/her family or his neighbours.