Trauma Interventions using Mindfulness Based Extinction and Reconsolidation (TIMBER) psychotherapy prolong the therapeutic effects of single ketamine infusion on post-traumatic stress disorder and comorbid depression: a pilot randomized, placebo-controlled, crossover clinical trial

Pradhan and colleagues frame post-traumatic stress disorder (PTSD) as a condition driven by pathological trauma memories (TMs) that underlie intrusive recollections, avoidance, numbing and hyperarousal. The authors note that many existing treatments do not directly target these trauma memories, which may contribute to incomplete responses: fewer than 60% of patients respond to frontline SSRIs, and prolonged exposure therapy has 20–30% dropout rates. They introduce Trauma Interventions using Mindfulness Based Extinction and Reconsolidation (TIMBER) as a mindfulness-based cognitive behavioural approach that integrates graded exposure and reconsolidation strategies to modify trauma memories while avoiding re-traumatisation, and they highlight prior evidence that low-dose (R,S)-ketamine produces rapid but short-lived improvements in PTSD and comorbid depression. This pilot study therefore set out to test whether combining a single low-dose (R,S)-ketamine infusion with a programme of TIMBER psychotherapy would produce a synergistic and more durable clinical response in chronic, treatment-refractory PTSD. The investigators designed a randomised, double-blind, placebo-controlled, crossover trial to compare TIMBER plus ketamine (TIMBER-K) against TIMBER plus saline (TIMBER-P), with primary outcomes focused on PTSD symptom scales (CAPS and PCL) and secondary outcomes including measures of depression, anxiety and cognition. The authors emphasise the use of a targeted reconsolidation window (the first 6 hours after controlled trauma memory reactivation) as a mechanistic rationale for combining peri-infusion TIMBER procedures with ketamine.

This was a randomised, double-blind, placebo-controlled, crossover pilot trial conducted at Cooper University Hospital and Cooper Medical School of Rowan University. Ten adults with chronic, treatment-refractory PTSD (refractory for at least 6 months and having received CBT plus at least two antidepressants) were randomised 1:1 into two arms (n = 5 each): TIMBER-K (single intravenous infusion of 0.5 mg/kg R,S-ketamine plus 12 TIMBER sessions) and TIMBER-P (single infusion of normal saline plus 12 TIMBER sessions). The pharmacist and statistician were unblinded; all other study personnel remained blinded. Recruitment occurred over approximately 2 months and the manuscript reports follow-up assessments carried out for an extended period (the extracted text inconsistently refers to both 18 months and one year of follow-up). The infusion protocol administered 0.5 mg/kg R,S-ketamine (240 mL solution) or equal-volume saline over 40 minutes with standard peri-procedure monitoring; an attending anaesthesiologist was present and authorised to treat marked hypertension or tachycardia, which did not occur. TIMBER comprised a peri-infusion mini-TIMBER/STOPP module (two 10-minute cycles during the peri-infusion window, which included 10 minutes pre-infusion, 40-minute infusion, and 10 minutes post-infusion) designed to combine controlled, brief trauma-memory reactivation with rapid de-escalation and mindful detached monitoring. After the infusion period, participants practised mini-TIMBER at home twice daily until relapse; on relapse they received nine weekly full TIMBER sessions (40–45 minutes each) focused on mindfulness-based graded exposure therapy (MB-GET) and reconsolidation-based procedures. The TIMBER programme was personalised using an Assessment Scale for Mindfulness Interventions (ASMI) and a scripted narrative of the index trauma prepared during baseline assessment. Clinical assessments included clinician- and self-rated PTSD instruments (Clinician Administered PTSD Scale for DSM-IV, CAPS; PTSD Checklist, PCL), the 17-item Hamilton Rating Scale for Depression (Ham-D-17), Beck Anxiety Inventory (BAI), Montreal Cognitive Assessment (MoCA), and the Columbia Suicide Severity Rating Scale (C-SSRS). The text reports that PCL and BAI were administered at 240 minutes (4 hours) post-infusion and that the 480-minute (8-hour) assessment included PCL, BAI, MoCA and C-SSRS; however, responder definitions used 24-hour post-infusion scores (see below) and the extracted text does not clearly reconcile how 24-hour data were captured alongside the 4- and 8-hour timepoints. Primary outcomes were changes in CAPS and PCL; secondary outcomes included Ham-D-17 and BAI. Responder criteria required a ≥20-point reduction from baseline in both PCL and CAPS at 24 hours that was sustained for at least 7 days; depression response was defined as ≥50% reduction in Ham-D-17 at 24 hours. Remission and relapse thresholds were prespecified for each scale. Sample size calculations used a baseline CAPS mean of 92 and SD of 11 with a target between-group difference of 20 points to yield 80% power at two-tailed alpha = 0.05, giving five subjects per arm. Statistical analyses employed t-tests for continuous between-group comparisons, chi-square for categorical data, Z-statistics for percent-change comparisons, and Pearson correlation for associations; data were presented as mean ± SD and analysed with SPSS 23.0.

The study enrolled 10 participants (seven female, three male) with mean age 43 ± 13.3 years and mean education 13 ± 2.75 years. Trauma etiology included repeated sexual trauma (n = 7), motor vehicle accident (n = 2) and combat-related trauma (n = 1). Mean duration of PTSD was 19.2 ± 12.51 years; baseline mean CAPS was 92 ± 11, indicating severe PTSD, and baseline Ham-D-17 was 26.9 ± 6.17, indicating severe depression. Randomisation produced groups that were similar on age, education and PTSD duration, but the TIMBER-K arm comprised five females while the TIMBER-P arm had three males and two females (P = 0.038). Nine of 10 participants met the prespecified responder criteria: all five participants in TIMBER-K and four of five in TIMBER-P. There were no dropouts and the authors report an intention-to-treat analysis for the responders. Across responders, the mean duration of sustained clinical response was 31.78 ± 18.29 days, substantially longer than the typical 4–7 days reported after a single ketamine infusion alone. For primary outcomes, significant reductions were reported: PCL decreased from mean 75.11 ± 8.28 at baseline to 45.67 ± 19.55 at 4 hours (P = 0.003) and to 25.89 ± 6.01 at 24 hours (P < 0.001). CAPS decreased from 87.56 ± 8.08 at baseline to 20.00 ± 7.73 at 24 hours (P < 0.001). Secondary outcomes also improved markedly: Ham-D-17 fell from 26.11 ± 5.9 at baseline to 4.33 ± 2.55 at 24 hours (P < 0.001). BAI decreased from 48.89 ± 12.49 at baseline to 27.67 ± 15.31 at 5 hours (P < 0.005) and to 8.56 ± 4.67 at 24 hours (P < 0.001). Comparing arms, TIMBER-K had a numerically longer mean duration of response (33 ± 22.98 days) than TIMBER-P (25 ± 16.8 days) but this difference was not statistically significant (P = 0.545). There were no significant between-arm differences in percent change from baseline across timepoints using the reported Z-statistics. The ASMI (mindfulness) scores increased after five TIMBER sessions (50.80 ± 8.87 at baseline to 72.80 ± 8.74 after five sessions, P = 0.043); baseline ASMI correlated positively but not significantly with response duration (r = 0.53, P = 0.115). Per the crossover protocol, all five participants in the TIMBER-P arm who experienced sustained relapse were switched to TIMBER-K. In these crossover subjects, mean duration of response increased from 25 ± 16.58 days before ketamine to 49 ± 18.4 days after receiving ketamine (P = 0.028). Safety signals were limited: two participants had mild nausea within 1 hour post-infusion that resolved without intervention, no clinically significant cognitive side effects were observed, and the authors report no suicidal behaviour, no hospitalisations and no dropouts during the follow-up period described in the paper. The extracted text contains inconsistent statements about follow-up length (both 18 months and one year are mentioned).

Pradhan and colleagues interpret their pilot data as supporting the feasibility, acceptability and potential efficacy of combining TIMBER psychotherapy with a single low-dose (R,S)-ketamine infusion to achieve more sustained improvement in PTSD symptoms and comorbid depression and anxiety than would be expected from ketamine alone. They highlight that nine of 10 participants met stringent responder criteria and that the combined intervention produced a markedly longer mean duration of response than the commonly reported 4–7 days after a single ketamine infusion; crossover data from participants who moved from TIMBER-P to TIMBER-K showed a statistically significant prolongation of response. The investigators advance a mechanistic rationale centred on targeted use of the reconsolidation window during the first 6 hours after controlled trauma-memory reactivation. They propose that brief, therapist-guided reactivation followed by mini-TIMBER reconsolidation procedures during the peri-infusion window makes trauma memories labile and amenable to modification, while ketamine—via glutamatergic modulation or active metabolites such as hydroxynorketamine—increases synaptogenesis and plasticity to support new learning. The authors suggest that TIMBER's combination of extinction and reconsolidation techniques, delivered with mindful detached monitoring, helps reappraise and lower the threat value of trauma memories and that ongoing home practice consolidates these gains. They also note hypothesised involvement of fronto-limbic circuits (including amygdala–prefrontal pathways) but acknowledge that neuroimaging data to test these mechanisms were not collected in this study. Key limitations acknowledged by the authors include the small sample size inherent to the pilot design and incomplete clarity in follow-up duration within the extracted text (the manuscript refers both to 18 months and to one year of follow-up). They also note that the neural mechanisms remain speculative without functional imaging data. Despite these caveats, the authors consider the high remission and retention rates, the safety profile observed, and the crossover results as justification for further research, including larger randomised trials with longer and more clearly documented follow-up and mechanistic investigations to validate and extend these preliminary findings.