Although its rarity, psychiatrists should be aware of this diagnosis in elderly. The report of this cases could contribute to a better identification of clinical characteristics and additional risk factors.

A literature review about the potential of abuse with ketamine in the treatment of Major Depressive Disorder (MDD). Background:Ketamine is a non-selective N-methyl-D-aspartate (NMDA) receptor antagonist, that also has effect on κ-opioid and sigma receptors. (1) It has been used since 1970 as a dissociative anesthetic and gained popularity as a recreational drug in 1990 .(2) People misusing ketamine may report experiences of dissociation, derealization, depersonalization and hallucinations. (2) There is no data on the prevalence of ketamine nonmedical use, but its misuse has been increasing in the past decade and its illicit use poses major public health challenges in many countries. (1,3) Ketamine reinforcing effects are thought to be dopamine mediated, with rapid development of tolerance, thus leading to its potential for abuse and dependence. (4) It is a regulated substance in many countries for its liability for abuse. (5) . Besides this potential for abuse, urinary tract lesions and cognitive impairment are described in long-term use of ketamine. (6,7) Since 2000, ketamine is being studied as a potential treatment in Major Depressive Disorder (MDD), due to its modulation of glutaminergic system which is thought to be involved in depression pathophysiology. (8) Materials and Methods:The literature search was developed in the MEDLINE/Pubmed for relevant articles, using keywords for all variants of "ketamine", "depression" "abuse". Results:Several studies show that the use of a single infusion of subanesthetic dosing of ketamine reduces depressive symptoms and suicidal ideation in patients with refractory MDD within 4 hour to 1 day after administration. (9)(10)(11)(12)(13) These benefits seem to last 3-14 days after administration, (9,(13)(14)(15)(16) with relapse of symptoms being reported in some studies after treatment cessation, even in patients with repeated administrations of ketamine. (17)(18)(19)(20) With this growing evidence of a rapid antidepressant effect, numerous private clinics started offering ketamine as an off-label treatment for refractory depression, although the safety of repeated infusions of ketamine has not been fully investigated in large clinical studies (21) A systematic review that evaluated the side effects of ketamine use in depression, reported that short term psychiatric, psychotomimetic, cardiovascular and neurological effects were more frequently reported with ketamine than placebo but these were transient and associated with acute intravenous administration of ketamine. (22) Conclusions could not be drawn for repeated doses of ketamine, since insufficient data was available regarding the side effects of repeated dosing and possible cumulative and long-term risks, as known in other patient groups exposed to ketamine . (22) Two case reports described a development of ketamine dependence in persons who presented MDD. One paper described the case of a 52year-old man with a history of recurrent MDD, persistent depressive disorder and a previous treatment for alc...

Delusional beliefs typically involve intentional others (e.g., god, specific persons or organisations, etc.; Bell et al., 2017). Kapur (2003) hypothesised that psychosis is a state of aberrant salience, where delusions represent a top-down cognitive effort to make sense of the aberrantly salient experiences.• In contrast to negative symptoms that are associated with a theory of mind deficit, delusions, particularly the paranoid subtype, appear to be associated with excessive attribution of others' mental states, even when the situation does not necessarily require so, namely, a tendency of over-mentalisation (OM; e.g., Bliksted et al., 2017; Montag et al., 2011).• The current meta-analytic review aimed to collate current research on the relationship between over-mentalisation and delusions in patients with psychosis. A positive effect size between delusion severity and over-mentalisation was hypothesised.