Pathological jealousy, also known as morbid jealousy, Othello syndrome or delusional jealousy, is a psychological disorder in which a person is preoccupied with the thought that their spouse or sexual partner is being unfaithful without having any real proof, along with socially unacceptable or abnormal behaviour related to these thoughts. The most common cited forms of psychopathology in morbid jealousy are delusions and obsessions. It is considered a subtype of delusional disorder. Overvaluing an idea, which is defined as “an acceptable, comprehensible idea pursued by the patient beyond the bounds of reason. The idea is not resisted and, although it is not a delusion, the patient characteristically attaches utmost importance to investigating and maintaining the partner’s fidelity at great personal disadvantage and to the distress of the partner”. Overvalued ideas are characterized by being existent in the individual's own thoughts, being egosyntonic; meaning that the ideas project the behaviors, values, and feelings that are aligned with the desires and aims of the individual's ego, or consistent with the individual's ideal self-image, the ideas are also amenable to reason but are not resisted. Definition This disorder occurs when a person typically makes repeated accusations that their spouse or sexual partner is being unfaithful, based on insignificant, minimal, or no evidence, often citing seemingly normal or everyday events or material to back up their claims. Unlike other delusional disorders, people who suffer from this disorder have a strong association with stalking, cyberstalking, sabotage, or even violence. It can be found in the context of schizophrenia and delusional disorder, such as bipolar disorder, but is also associated with alcoholism and sexual dysfunction and has been reported after neurological illness (i.e. Parkinson's). The name "Othello Syndrome" comes from the character in Shakespeare's play Othello, who murders his wife as a result of a false belief that she has been unfaithful. Recently, some psychologists and psychiatrists have asserted that Othello was deceived rather than deluded about Desdemona's alleged infidelity and thus did not have ‘the Othello Syndrome’. Psychiatric history Presenting difficulties: neurotic or psychotic jealousy Past psychiatric history: neurotic or psychotic disorders, deliberate self-harm and attempted suicide Family history: mental illness including pathological jealousy Relationship history: incorporating both the current and previous relationship and taking account of the quality of the relationships and the difficulties experienced Forensic history: previous and pending charges and convictions as well as deviant behavior which was not reported or did