The terms "delusional" and "psychotic" are both used in psychiatry, but they refer to somewhat different concepts.
Delusions are one symptom of psychosis. A delusion is a false, fixed belief that is held with absolute certainty, even when there is strong evidence to the contrary. Delusions can take various forms, such as grandiose delusions (beliefs of exaggerated importance, power, knowledge, or identity), persecutory delusions (beliefs of being targeted or persecuted), or somatic delusions (beliefs of having a physical illness or abnormality).
However, not all delusions are equal in their intensity or impact on a person's life. When we talk about "mildly delusional", it could refer to delusions that are less firmly held, less disruptive to a person's life, or perhaps less detached from reality than more severe delusions. However, it's important to remember that even mild delusions represent a significant departure from reality.
Psychosis, on the other hand, is a state characterized by a loss of contact with reality. It's not a disorder in itself, but a symptom of several mental health disorders like schizophrenia, schizoaffective disorder, and bipolar disorder, or even due to certain medical conditions or substances.
Psychosis includes a range of symptoms, not just delusions. It may also involve hallucinations (seeing or hearing things that aren't there), disorganized thinking (evident in disordered speech), and grossly disorganized or abnormal motor behavior (including catatonia).
So, while being delusional is part of being psychotic, psychosis refers to a broader range of symptoms. In other words, someone experiencing psychosis might have delusions, but they could also have other symptoms such as hallucinations or disorganized thinking.
As with all mental health conditions, these experiences can vary widely between individuals, and it's important for a healthcare professional to make a diagnosis and treatment plan based on a comprehensive evaluation of the individual's symptoms and circumstances.