The Halifax study: ISTDP for treatment-resistant depression
The Halifax study tested time-limited ISTDP for depression that persisted despite previous antidepressant treatment. The results favoured ISTDP compared with treatment as usual in specialist psychiatric care.
When previous treatment has not been enough, we need to explore what other possibilities there are. The Halifax study from 2017 and its follow-up from 2020 contribute to that question for ISTDP, intensive short-term dynamic psychotherapy.
Sample and design
In the randomised trial, 60 patients were allocated to ISTDP or treatment as usual, 30 in each group. Among the inclusion criteria were major depression, persistent symptoms after at least six weeks of antidepressant treatment and a score of at least 16 on the Hamilton Depression Rating Scale, HAM-D.
ISTDP was delivered in a format of up to 20 sessions. The comparison group received routine specialist psychiatric care, which could include medication and talking therapy.
Measures and results
The primary outcome measure was depressive symptoms on the HAM-D after six months, rated by assessors who did not know the group allocation. Patients’ self-reports on the PHQ-9 were a secondary measure.
Symptom reduction was statistically significantly greater in the ISTDP group. The between-group effects at six months were Cohen’s d = 0.75 for the HAM-D and 0.85 for the PHQ-9.
Follow-up and attrition
Follow-up covered 18 months from the start of the study, around one year after ISTDP had ended. Analyses showed that the difference in depressive symptoms favouring ISTDP remained. At the final measurement, 37 of the original 60 patients took part. The intention-to-treat analysis used available data from all participants, but attrition limits the certainty of the long-term findings.
The health economic analysis also suggested cost-effectiveness, with uncertainty concerning, among other things, the handling of missing data. This is a result from the care setting studied, not a statement about costs in Swedish healthcare.
What can we conclude?
The results support ISTDP as a treatment option for the patient group studied. However, the comparison with treatment as usual does not show how ISTDP compares with an equally extensive, structured psychotherapy. The sample was small and treatment was delivered by experienced ISTDP therapists. Replication in larger, independent studies is needed to assess how well the results hold up in other treatment settings.
Does this text raise questions about your own situation?
If you would like to explore them in a session, you are welcome to book an appointment or ask me first.