Child Abuse and neglect by parents is a risk factor for Psychotic Disorders.

The existence of early-onset psychosis in children has been questioned owing to the difficulty in differentiating a psychotic disorder and a childhood fantasy as part of normal development. However, childhood psychotic disorders are now well-known entities; their clinical presentation in childhood differs from the adult form, but both are considered to have the same pathology.

Child abuse and neglect by parents and other caregivers can be considered a risk factor for psychotic disorders owing to the biological mechanisms and the activation of cortisol by the hypothalamic–pituitary–adrenal axis. In addition, gene–environment interactions are likely to play a role in the relationship between childhood trauma and psychosis.

Child abuse and neglect is a complex experience that includes emotional, physical, and sexual abuse, as well as emotional and physical neglect. This childhood adversity can be associated with future mental disorder. Because child abuse occurs during the critical formative period in which the brain is being physically sculpted, the impact of extreme stress can leave an indelible mark on the brain’s structure and function. Such abuses seem to induce a cascade of molecular and neurobiological effects that irreversibly alter neuronal development, enabling the individual to develop psychiatric symptoms such as psychosis, aggression, and anxiety, and even influencing the way they perceive the environment and the people around them.

it is possible for individuals to develop a shared psychotic disorder, also known as folie à deux. This is a very rare psychiatric syndrome in which a psychotic symptom is induced in one individual by another. Its main feature is a delusion that develops in an individual who is involved in a close relationship with the “inducer” or “primary case,” who already has a psychotic disorder with prominent delusions. The syndrome is called a shared psychotic disorder in the Diagnostic and Statistical Manual of Mental Disorders fourth edition (DSM-IV), but it is not present in the current DSM-V. In the 10th edition of the International Classification of Disease, the disorder is called induced psychotic disorder.

In shared psychosis, the individual who is influenced by the inducer is someone who possibly has low intelligence. They are also shy, passive, and have lower self-esteem than the inducer, often living in a constant relationship with the latter and almost completely isolated from the rest of the world, and unrelated to a network of social contacts.

Schizophrenia is probably the most common diagnosis of the Primary case, although other diagnoses may include delusional disorder or mood disorder with psychotic features. The content of the shared delusional beliefs may depend on the diagnosis of the primary case and can include bizarre delusions, delusions congruent with the mood, or non-bizarre delusions characteristic of delusional disorder.