Bipolar disorder and psychosis

This article by Dan Polansky intends to investigate the relation of bipolar disorder to psychosis (hallucinations, delusions).

Initial questions to be considered:

• Is psychosis a possible symptom of bipolar disorder?
• Is psychosis a typical symptom of bipolar disorder? Quantitatively, how common is psychosis in bipolar disorder?
• If the above is true, would bipolar disorder properly classified as a psychotic disorder?
• If the above is true, what is the difference between a bipolar disorder and schizoaffective disorder, both featuring an affective component and a psychotic component?
• If psychosis is a symptom of bipolar disorder, is it associated with the manic phase, the depressive phase or both?

Not all of these questions need to be addressed in the initial draft.

As for bipolar disorder having psychosis as a possible symptom:

• It is so per Britannica, NIMH, Mayo Clinic and NHS. The language used in the sources cannot be used to support psychosis being a very common symptom, and thus, this leaves this question open.
• As per Cleveland Clinic, "They also occasionally develop psychotic symptoms, such as delusions and hallucinations, which can cause difficulties in distinguishing bipolar disorder from other disorders such as schizophrenia or schizoaffective disorder.".

As for how common psychosis is in bipolar disorder:

• Chakrabarti 2022 states: "Lifetime psychotic symptoms are present in over half of the patients with bipolar disorder (BD) [...]", without line tracing it to any source.
• psychcentral.com states: "And, according to a 2000 study, more than half of people with bipolar disorder will experience psychosis at some point." However, the article states that "Psychosis is loss of contact with reality", which is very inaccurate.
• Burton 2017 or 2019 states: "The prevalence of psychosis in this sample (53%) was similar to published reports." It is not prefectly clear whether this should be interpreted as saying that psychosis is seen in approximately 50% of people with bipolar disorder.
• Grover 2022 states: "42.2% patients had at least one psychotic episode in their lifetime"
• camh.ca states: "Approximately 50 to 95 percent of people with bipolar disorder experience psychosis. Psychotic features usually appear during manic rather than depressive episodes."

A reasonable conclusion from the above sources is that psychosis is seen in approximately one half of bipolar disorder patients at least once during their lifetime. However, it is not clear how to square this conclusion with the language of occassionally of Cleveland Clinic quoted above.

As for classification of bipolar disorder as affective vs. psychotic disorder:

• ICD-10 has bipolar disorder as category F31, a subcategory of F30-F39 Mood [affective] disorders.. ICD-10 has "F25 Schizoaffective disorders" as part of "F20-F29 Schizophrenia, schizotypal and delusional disorders".
• Since we have above that about half of bipolar patients have at least one psychotic episode, the above ICD-10 structure, including its labeling, seems positively misleading.
• It seems likely that bipolar disorder, schizophrenia and schizoaffective disorder are part of the same multidimensional symptom space, which some sources refer to as part of a spectrum. If so, it is not a single-dimensional transition from schizophrenia to bipolar disorder through schizoaffective disorder, but there are at least two dimensions allowing various combinations, the degree of presence of bipolar affective symptoms and the degree of presence of psychotic (hallucinations, delusions) symptoms.
• A remedy could be this: in case of doubt, classify all three items as a single item called schizoaffective disorder (whose name recognizes both schizo- and and affect- components), and focus on individual symptoms rather than assignment to one of the three allegedly distinct categories existing in reality. However, the matters may be not so simple; the three items can in principle exist as cluster centers of real data. That would have to be properly investigated.
• Be it as it may, one is perhaps well advised to suspect widespread miscategorization or arbitrary categorization as for the three putative categories of schizophrenia, schizoaffective disorder and bipolar disorder. Meyer 2009 deals with a possible misdiagnosis.
• The matter is complicated by unipolar depression also sometimes having psychotic symptoms. Indeed, schizoaffective disorder is subcategorized in the literature as having the affective component unipolar or bipolar. This could lead to a tentative conclusion that the whole split of disorders into mood/affective disorders and psychotic disorders is artificial and not corresponding to reality.

Further reading

• Bipolar disorder, wikipedia.org
• Schizoaffective disorder, wikipedia.org
• Psychosis, wikipedia.org
• Psychotic depression, wikipedia.org