Factitious disorder is characterized by a pattern of abnormal behavior in which patients deliberately produce, falsify, or exaggerate physical and/or psychological symptoms that have no, or little, organic basis, to assume the sick role (1). Factitious disorder can be misdiagnosed as conversion disorder, but in conversion disorder the production of physical and/or psychological symptoms is unconscious, whereas in factitious disorder this production is conscious. Factitious disorder can also be imposed on other people, when the perpetrator actively harms his victims in order to make them ill. In such a case, the disorder is also called Munchausen Syndrome by proxy. Factitious disorder imposed on another can involve a dependent adult, an elderly person, or a child as a victim and, in the latter case, it is a form of childhood abuse (2, 3). Factitious disorder was first described by the British psychiatrist Asher in 1951, and named after Baron Hieronymous Karl Friedrich von Münchausen (1720–1791), a German officer who was known for telling invented and unbelievable stories about himself and his life (4) The American Psychiatric Association first included factitious disorder in Diagnostic and Statistical Manual of Mental Disorders (DSM) III: Diagnostic and Statistical Manual of Mental Disorders in 1980 (5). However, despite decades have passed since the inclusion of factitious disorder in the DSM manual, its incidence remains controversial (6, 7). According to DSM-5, factitious disorder in hospital settings is estimated to be present in 1% of individuals (1). Skin alteration (i.e., ulcers, dermatitis artefacta, hyperkeratosis) is the most common presentation of factitious disorder (8, 9), but factitious disorder appears to be common also in neurological settings, where it represents up to 30% of neurologist consultations (10).

In the context of factitious disorder, depression can be both a feigned disease and an associated comorbidity. However, since most patients with factitious disorder reject psychiatric consultation, its real prevalence is likely underestimated (6, 11). As a consequence, only a few patients with factitious disorder that also present with depression receive an adequate psychiatric diagnosis (12). Moreover, it is important to note that not all patients with factitious disorder suffer from depression, and literature on risk factors for depression development in factitious disorder patients is scarce and has never been put into a congruent frame. Based on these premises, the present study aimed to: 1. Provide an overview of the relationship between factitious disorder and depression; 2. Identify the prevalence of depression in factitious disorder; 3. Identify factors that can contribute to the development of depression in patients suffering from factitious disorder.

The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (13). A literature search was performed using the electronic databases PubMed, EMBASE and Cochrane Library, using a combination of the following MESH terms: “factitious disorder”, “Munchausen Syndrome”, “depression”, “depressive disorder” and “depressive episode. The search was conducted on December 9^th, 2022. Studies were eligible for inclusion in this review if they investigated factitious disorder imposed on self or imposed on another with comorbid depression. Only original papers published in English, French or Italian in peer-reviewed journals were accepted for inclusion. No predefined time window for the study search was adopted, to be the most inclusive as possible. By using a three-step screening approach, articles were screened through title, abstract, and full-text reading, if needed. Studies were excluded if they (i) reported on children and adolescents; (ii) provided mainly commentary or proposed guidelines; (iii) did not assess depression in factitious disorder; or (iv) reported on factitious depression. The screening and data extraction was done manually. Publication data screening and extraction were performed following a 2-step selection process (conventional double-screening) conducted by two reviewers independently of each other (CC and DMM). In the rare instances of discrepant screening, a consensus was reached through discussion with a third senior clinical researcher (MC). Further research evidence, gathered outside of the search or identified through manual search of the reference section of the included articles, was reported if considered appropriate by researchers. By applying a flexible approach, other articles that were deemed to cover prominent related topics were also searched by accessing grey literature and/or screening the reference lists of the eligible studies, to provide a more comprehensive overview (See Figure 1 – flow chart). The following information was extracted from the included studies: Study ID (including authors, year of publication and country in which the study was conducted), study design characteristics (including study type, number of patients and patients’ sex and age), brief description of symptoms presentation, diagnostic tools used and risk factors for depression.

A total of 2288 articles were identified and cross-checked by two researchers. By using a three-step screening approach, titles, abstracts, or full texts of all records were screened against the inclusion and exclusion criteria. A total of 22 articles were included, consisting of n = 18 case reports (2, 6, 12, 14–28) and n = 4 cohort studies (9, 11, 29, 30).

The studies were conducted in 13 countries, with 33% of them being performed in the United States (US), 33% in the European Union (EU), and 33% in Turkey, Morocco, Canada, and India, by involving from 1 to 60 patients, mainly female. The most common presentation of factitious disorder was skin lesions (n = 11) and hypoglycemia (n = 2). Beyond this, there was a wide range of presentations, such as factitious mourning, Acquired immune deficiency syndrome (AIDS), cancer, Cushing syndrome, vomiting, and anaphylaxis.

This review found depression to be highly prevalent in factitious disorder, affecting around 30% of the samples. This result provides support for an association between factitious disorder and mood disturbance (34). According to evidence gathered in this review, signs and symptoms of depression in factitious disorder are identical to those expressed by patients with depression who do not have a factitious disorder. For this reason, depression among factitious disorder patients is expected to be easily identified by an expert psychiatrist. Diagnostic tools for depression can be used, as well as projective tests. Projective tests can be especially helpful when factitious depression is suspected. The theoretical basis for use of projective measures is that in the absence of specific instruction or highly directive stimuli, people will have only their own internal resources available for managing the demands of the test. Thus, they will project their own internal psychological functioning onto the test stimuli (31).

Results of our review suggest that patients with factitious disorder and comorbid depression who receive antidepressant treatment improve both in factitious and depressive symptoms. Therefore, early detection and treatment of depressive symptoms in this population appears to be crucial also for the management of the factitious disorder. Factitious disorder diagnosis is often problematic due to the nature of the disorder that leads clinicians to focus more on somatic symptoms rather than on psychological problems, at least at first. The exaggerated, atypical, and contradictory presentation of factitious disorder symptoms is likely to lead clinicians to perform unnecessary diagnostic tests and invasive diagnostic procedures and to prescribe unnecessary treatments and needless hospitalization, also to avoid exposure to malpractice litigation (35, 36). Patients’ seeking attitude towards procedures and treatment goes along with clinicians’ fears of litigation, which can result in important delays in factitious disorder diagnosis. Moreover, the focus on somatic complains and the waiting for procedure results may lead clinicians to underestimate levels of emotional distress in patients with factitious disorder (6). Indeed, it is likely that there is a significant window of time in which depression in factitious disorder goes undetected. Importantly, delays in depression treatment in patients with factitious disorder have been related to poor prognosis and high risk of chronicity of both depressive and factious symptoms (37).

Reported risk factors for depression in factitious disorder overlap with risk factors for factitious disorder with regard to childhood trauma and history of psychiatric disorder. The association between childhood adversities and the subsequent development of depression in adult life has been extensively studied (38). Childhood abuse involves experiences of being rejected, degraded, terrorized, isolated or teased. When childhood abuse is perpetrated by caregivers, it affects secure attachment, which can lead to the development of distorted and negative internal working models of the self and the others (39). Childhood abuse and insecure attachment are also linked to alexithymia, which is the inability to express and regulate emotions. Alexithymia is often found across several mental disorders, including depression. Further, such inability to recognize others’ emotions and to properly express one’s own emotions can lead to the development of somatic symptoms. The production of somatic symptoms, either conscious or unconscious, may thus be functional to avoid trauma-related symptoms. People exposed to childhood traumatic experiences are more likely to develop emotional distress compared to non-exposed. Emotional distress may lead to emotional fragility, feelings of insecurity, social isolation, low self-esteem, and loneliness intolerance, that also continue into adult life, leading to the development of a factitious disorder with comorbid depression (6, 28). With regard to having a history of psychiatric disorder, it is known that some psychiatric disorders, such as bipolar and personality disorders, are at high risk to present with depressive episodes. For this reason, it is likely that having a factitious disorder and a history of psychiatric disorder increases the odds of developing depression. Instead, specific risk factors for depression in factitious disorder seem to include having suffered from adulthood traumatic experiences, especially mourning. Under this perspective, factitious disorder symptoms may act as a try to avoid the foster of complex situations related to traumatic experiences underlying depression.

Given the high prevalence of depression in factitious disorder, a multidisciplinary team approach in cooperation with mental health professionals appears to be essential for the management of these patients. However, this field of research is still sparse and mainly based upon case-report studies, suggesting the need to increase research in this area with more robust investigations.

The original contributions presented in the study are included in the article. Further inquiries can be directed to the corresponding author.

CC: Conceptualization, Data curation, Investigation, Methodology, Resources, Validation, Visualization, Writing – original draft, Writing – review & editing. DMM: Conceptualization, Data curation, Investigation, Resources, Validation, Visualization, Writing – original draft, Writing – review & editing. RB: Conceptualization, Data curation, Investigation, Resources, Validation, Visualization, Writing – review & editing. AP: Conceptualization, Methodology, Resources, Supervision, Validation, Visualization, Writing – review & editing. MB: Conceptualization, Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing – review & editing. MC: Conceptualization, Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing – review & editing.