Cases are dependent on the type of delusion shared. One partner usually faces a problem in the society that involves the intervention of a psychiatrist. Often, this problem is supported or under the influence of the other partner. Both exhibit unrealistic fixed false beliefs which are unshakable. They might be paranoid, fearful and suspicious of a neighbor or someone in their community. One might seek mental assessment after risky behavior, unreal claims, or recent assault. The secondary partner could be mistakenly referred and usually discovers that other people within his/her social sphere share the same belief as the primary. There could be under-treated or even undiagnosed cases within the community that last for several years before being discovered. Sometimes partners who shared particular delusions could be admitted inside the hospital together because of risky behavior or assault to themselves or others.

General description: The couples usually looking decent, well dressed and groomed.

Behavior: Defensive attitude or angry behavior could result in the patient towards an interviewer who challenges his/her delusions.

Speech: The speech is usually coherent and relevant.

Mood/Affect: Mood is usually congruent with the delusion; a paranoid patient may be irritable, while a grandiose patient may be euphoric.

Thought: The form of thought is usually directly goal oriented. The delusions are shared either entirely or partially, often not bizarre in content and are gradually systematically structured, overvaluing social/cultural/religious beyond the usual community norms or the presence of homicidal or suicidal plans.

Perceptions: They are less likely to express abnormal perceptions unless there are predisposing factors. Sometimes the secondary is the only person who experiences a form of hallucinations.

Orientation and Cognition: The patient usually oriented to time, place and person, unless being driven by his delusion. Memory and cognition are generally not affected.

Risks: It is crucial to evaluate the patient for suicidal or homicidal ideations and plans. If there is a history of aggression with adverse outcome, then hospitalization should be considered.

Insight and judgment: Most commonly patients and their partner have no insight regarding their mental illness. Judgment is assessable by questioning the history of past behavior and a future plan.[9][12][13]

As with any other psychiatric disorders, no specific labs are necessary for shared psychotic disorder.  Most of the investigations whether Imaging or laboratory tests should be considered to rule out any organic causes. A urine toxicology screen is vital to rule out any substance-induced conditions. If there are no medical/substance-induced condition, a full assessment should is next. It would be helpful to ask for collateral history about both partners from a third person. It is common to take history only from one of the partners because of strict social isolation situation; this would carry a great challenge for the psychiatrist. After taking a history, the psychiatrist should conduct a complete mental state examination. Collecting further details from other members of the family or friends should help in evaluating the case. The primary partner can be defensive and misleading leading to encapsulate the delusion; this will hide the symptoms for years unless s/he was acting on it.

Treatment should be tailored case by case. If there is an under-treated case, efforts should encourage increased adherence to the treatment plan. There have been suggestions that separation from the primary improves the condition significantly. After admission, the influence of the primary partner gradually disappears. It is worth noting, however, that recent data suggest that separation by itself could be insufficient or may aggravate the condition.[3][14] Treatment with medication for both partners whether alone (antipsychotics-antidepressant) or in combination (mood stabilizers/antipsychotics) and (antidepressants/antipsychotics) could improve the condition.[3] Those started on medications indicate that their condition is severe and likely to express residual symptoms. It is critical follow up with cases because of a possible alternative diagnosis. Psychotherapy could be offered to both partners either individually or as conjoined-psychotherapy.[7] ECT has also been an option.[3]

The differential diagnosis could be ruled out based on the history of the association between both partners. The onset of the condition usually precedes the onset of the shared delusions. The diagnosis of shared psychotic disorder should always only be made after ruling out any organic causes or substance induced.

• Schizophrenia/Schizoaffective: This could be differentiated if the case reported other findings that are not being influenced by the primary, i.e., hallucinations, disorganized speech, grossly disorganized or negative symptoms. In the case of schizoaffective, an affective component should be present.
• Mood Disorder with Psychotic features: THis condition has a specific delusion which is mood congruent and not shared but expressed independently.

In case that the delusions do not disappear when the partners are separated, it is important to reassessment and consideration for an alternative diagnosis.

The prognosis of shared psychotic disorder is challenging to estimate, as it depends on multiple risk factors including the primary mental disorder and the secondary biopsychosocial predisposing factors. Theoretically, children are more likely to benefit from separation than adults. The adherence on management plan in both partners could provide a better outcome than being untreated. The assessment of nature or the duration of exposure to the delusion could provide clues on the outcomes of the disorder. Having premorbid personality features or predisposing risk factors could complicate the condition leading to consider an alternative diagnosis.[6]

The patients are not discovered easily due to lack of insight. They are usually referred after a complication, namely acting on such delusions that jeopardize their life or others. for example, a patient acts on his/her paranoid delusions through multiple accusations or commits an assault. Having delusions of grandeur or religious delusions could cause a hazard to others.[9]

Patients with shared psychotic disorder could be undiagnosed because only the primary partner gets registered for treatment in a classical presentation. The level of tolerance and harmony among the two patients both could add a significant challenge to the clinician to identify every partner's role. Awareness is necessary regarding the nature of the dyad relationship dynamics and to manage it extensively. Most patients lack insight, which causes a substantial barrier to early discovery and management. The failure to adhere to treatment is an additional challenge to the clinician. A key aspect is to understand the impact of the delusions on both partner’s life. A board-certified psychiatric pharmacist should work with the team to select the best agents for optimal therapeutic results with minimal adverse effects. A holistic approach that assesses and manages the biopsychosocial factors should help for a better outcome. The psychotherapist, mental health nurse, and psychiatrist should continue to follow these patients as relapse is common due to noncompliance with treatment.

Shared psychotic disorder requires a comprehensive interprofessional team approach, that includes physicians, specialists, specialty-trained nurses, and pharmacists, working and communicating together in a team approach to lead to optimal treatment and outcomes. [Level V]