Thought insertion is the idea that another thinks through the mind of the patient. The patient may sometimes be unable to distinguish between their own thoughts and those inserted into their minds. A patient who is diagnosed with this disorder is found to be convinced of their beliefs and unwilling to accept such diagnosis. It is a symptom of psychosis

Psychosis

Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...

 which occurs in many mental disorders and other medical conditions. Thought insertion along with thought broadcasting

Thought broadcasting

Thought broadcasting is a positive symptom of schizophrenia in the diagnostic process undertaken by mental health professionals. Thought broadcasting has been suggested as one of the so-called "first rank symptoms" believed to distinguish schizophrenia from other psychotic disorders.During thought...

, thought withdrawal

Thought withdrawal

In psychiatry, thought withdrawal is the delusion that thoughts have been 'taken out' of the patient's mind. It often accompanies thought blocking. The patient may experience a break in the flow of their thoughts believing that the missing thoughts have been withdrawn from their mind by some...

, thought blocking

Thought blocking

Thought blocking, a phenomenon that occurs in people with psychiatric illnesses , occurs when a person's speech is suddenly interrupted by silences that may last a few seconds to a minute or longer. Blocking is often brought on by questioning or discussing something of particularly large personal...

as well as other first rank symptoms are primary symptoms and should not be confused with the delusional explanation given by the respondent.

The ICD-10 defines thought insertion as the feeling that your thoughts are not your own. The person experiencing the thought insertion will not necessarily know where the thought is coming from.