Inadequate response to first- and second-line pharmacological treatments for psychiatric disorders is commonly observed. Ketamine has demonstrated efficacy in treating adults with treatment-resistant depression (TRD), with additional off-label benefits reported for various psychiatric disorders. Herein, we performed a systematic review and meta-analysis to examine the therapeutic applications of ketamine across multiple mental disorders, excluding mood disorders.

We conducted a multidatabase literature search of randomized controlled trials and open-label trials investigating the therapeutic use of ketamine in treating mental disorders. Studies utilizing the same psychological assessments for a given disorder were pooled using the generic inverse variance method to generate a pooled estimated mean difference.

The search in OVID (MedLine, Embase, AMED, PsychINFO, JBI EBP Database), EBSCO CINAHL Plus, Scopus, and Web of Science yielded 44 studies. Ketamine had a statistically significant effect on PTSD Checklist for DSM-5 (PCL-5) scores (pooled estimate = ‒28.07, 95% CI = [‒40.05, ‒16.11], p < 0.001), Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) scores (pooled estimate = ‒14.07, 95% CI = [‒26.24, ‒1.90], p = 0.023), and Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores (pooled estimate = ‒8.08, 95% CI = [‒13.64, ‒2.52], p = 0.004) in individuals with PTSD, treatment-resistant PTSD (TR-PTSD), and obsessive compulsive disorder (OCD), respectively. For alcohol use disorders and at-risk drinking, there was disproportionate reporting of decreased urge to drink, increased rate of abstinence, and longer time to relapse following ketamine treatment.

Extant literature supports the potential use of ketamine for the treatment of PTSD, OCD, and alcohol use disorders with significant improvement of patient symptoms. However, the limited number of randomized controlled trials underscores the need to further investigate the short- and long-term benefits and risks of ketamine for the treatment of psychiatric disorders.

Reassurance seeking (RS) in obsessive compulsive disorder (OCD) is commonly addressed in cognitive behavioural therapy (CBT) using a technique called reducing accommodation. Reducing accommodation is a behaviourally based CBT intervention that may be effective; however, there is a lack of controlled research on its use and acceptability to clients/patients, and case studies suggest that it can be associated with negative emotional/behavioural consequences. Providing support to encourage coping with distress is a cognitively based CBT intervention that may be an effective alternative, but lacks evidence regarding its acceptability.

This study aimed to determine whether support provision may be a more acceptable/endorsed CBT intervention for RS than a strict reducing accommodation approach.

Participants and familiar partners (N = 179) read vignette descriptions of accommodation reduction and support interventions, and responded to measures of perceived intervention acceptability/adhereability and endorsement, before completing a forced-choice preference task.

Overall, findings suggested that participants and partners gave significantly higher ratings for the support than the accommodation reduction intervention (partial η2 = .049 to .321). Participants and partners also both selected the support intervention more often than the traditional reducing accommodation intervention when given the choice.

Support provision is perceived as an acceptable CBT intervention for RS by participants and their familiar partners. These results have implications for cognitive behavioural theory and practice related to RS.

We performed functional magnetic resonance imaging (fMRI) to discriminate the differential brain activation patterns in patients with obsessive compulsive disorder (OCD) and healthy controls during implicit retrieval tasks with emotionally neutral and unpleasant words.

Sixteen patients with OCD (mean age: 31.4±10.1 years) and 16 healthy controls (mean age: 32.6±5.8 years) with no history of neurological or psychiatric illness underwent 3-T fMRI. The stimulation paradigm consisted of the following cycle: rest, encoding of a string of two-syllable words, rest, and retrieval of the previously encoded words with the first consonant omitted.

During the implicit retrieval task with emotionally neutral words, no distinct brain activity was observed in either the patients with OCD or healthy controls. On the other hand, during the retrieval task with unpleasant words, the patients with OCD showed predominant activity in the superior/middle temporal pole, medial superior frontal gyrus, and orbitofrontal cortex (uncorrected p<0.001, extent threshold: 30 voxels), whereas the healthy controls did not show any distinct regions of activation.

This study revealed the differential brain activation patterns between patients with OCD and healthy controls during implicit memory tasks with unpleasant words. Our results suggest that the impact of negative emotion on implicit memory task may be associated with the symptomatology of OCD. This finding may be helpful for understanding the neural mechanisms that underlie implicit memory retrieval, particularly the interaction between emotion and cognition, in patients with OCD.