Methods: This was a retrospective cohort study based on the analysis of electronic health records for N = 2064 patients treated for PTSD across 16 psychological therapy services in England. The Revised Impact of Events Scale (IES-R) scale was used to measure PTSD severity and associations were examined with the neighbourhood-level index of multiple deprivation (IMD) using non-parametric correlations and multilevel modelling.

Results: Three times more PTSD cases (33.6% vs. 9.7%) were clustered within the most deprived IMD quintile compared to the least deprived quintile. A small and statistically significant correlation between IMD and IES-R baseline severity (r = −0.16, p < .001), indicated that patients living in the most deprived neighbourhoods had more severe symptoms. Post-treatment IES-R severity was also significantly associated with IMD (B = −0.74, p < .001), after controlling for baseline severity of PTSD and comorbid depression symptoms, adjusting for between-service variability in treatment outcomes (ICC = 0.023). Treatment duration was a moderator of the association between IMD and treatment outcomes.

Conclusions: Neighbourhood deprivation is associated with a higher prevalence of PTSD, higher symptom severity at the start of treatment and poorer treatment response. A longer course of therapy mitigated the adverse impact of deprivation on treatment outcomes.

Highlights:

• Most patients seeking psychological therapy for PTSD tended to live in socioeconomically deprived neighbourhoods.
• Patients living in deprived neighbourhoods had more severe symptoms of PTSD before therapy, compared to those living in more economically advantaged neighbourhoods.
• Patients living in deprived neighbourhoods also had poorer treatment response, unless they received lengthier interventions – which improved outcomes.”