Any insights on when does *neurosis* become *psychosis*?

Neurosis doesn't: usually morph into psychosis.

Difference: A neurotic disorder can be any mental imbalance that causes or results in distress. In general, neurotic conditions do not impair or interfere with normal day to day functions, but rather create the very common symptoms of depression, anxiety, or stress. It is believed that most people suffer. Psychosis, or a psychotic disorder, is believed to be more of a symptom than a diagnosis. As a psychiatric term, psychosis refers to any mental state that impairs thought, perception, and judgement. Psychotic episodes might affect a person with or without a mental disease. A person experiencing a psychotic episode might hallucinate, become paranoid, or experience a change in personality.