Othello syndrome - Delusional disorder and mania- Bipolar spectrum disorder are distinct psychiatric conditions.
Othello syndrome, also known as delusional jealousy, is characterized by an intense, unfounded belief that a partner is unfaithful, leading to obsessive thoughts, compulsive checking, and aggressive or controlling behaviors. Common causes is neurotransmitter dysregulation leading to psychosis, substance use particularly alcoholism can be a trigger, genetics- strong family history of psychiatric disorders, neurological conditions; but cause is difficult to identify in majority of the cases.
Mania, on the other hand, is a mood state seen in bipolar disorder, characterized by elevated or irritable mood, hyperactivity, impulsivity, and sometimes delusions of grandeur or paranoia, heightened self esteem, reduced sleep, increased goal directed activity/increased psychomotor activity, loss of judgment.
While Othello syndrome focuses exclusively on delusions of infidelity, mania involves a broader spectrum of mood and behavioral dysregulation. A person suffering from mania can have various delusions and infidelity can be one of them.
Given the history and symptoms aren’t mentioned clearly in the question description, it’s difficult to comment on the diagnosis or differentials. Treatment approaches for both the conditions differ.
Next Steps
If the treatment taken till date isn’t showcasing any gross improvement, second opinion of a psychiatrist should be considered. Raise the concerns to the treating psychiatrist and try to establish a guideline of treatment and possible timelines for noticing improvements in the symptoms.