A recent study published in the Journal of Affective Disorders has provided new information on the most effective ways to deliver psychotherapy for depression in adults. Researchers have studied how various indicators of the number and frequency of psychotherapy sessions relate to treatment outcomes. The main findings suggest that although the number of sessions and total duration of contact with therapists do not have a significant impact on effectiveness, the frequency of sessions does.
Depression remains a significant public health challenge, being one of the leading causes of disability worldwide. Despite the proven effectiveness of psychotherapy in the treatment of depression, the optimal quantity and frequency of therapy sessions remains unclear.
Effective delivery of psychotherapy could potentially reduce the burden of illness by maximizing treatment effectiveness while minimizing costs. In their new study, the researchers sought to clarify the impact of the number and frequency of psychotherapy sessions on treatment effectiveness, thereby informing better clinical practices and better resource allocation.
“We know that depression in adults can be effectively treated with psychotherapy, but we are still not sure what quantity and frequency leads to the greatest effectiveness,” said study author Marketa Ciharova, doctoral student at Vrije Universiteit Amsterdam. “It’s important to know this so we can provide enough psychotherapy to be effective.” However, we also need to know when additional sessions do not improve the effects, because then we can save both client and therapist time. The therapist can then accept more clients, which is crucial especially these days when waiting lists for mental health care are very long.
The study used data from randomized controlled trials (RCTs) comparing face-to-face individual psychotherapy with control conditions such as usual care or waiting list. Meta-regression analyses, a statistical method that examines the relationship between study characteristics and treatment effects, were used to analyze the data.
The researchers conducted an extensive search of several bibliographic databases, including PubMed, PsycINFO, Embase, and the Cochrane Library, to compile relevant studies. The inclusion criteria were strict: studies had to be RCTs conducted on adult participants diagnosed with depression, comparing individual psychotherapy to a control condition. Group therapy, telephone therapy, and self-help interventions were excluded to ensure consistency of analysis.
Data from 176 studies involving 15,158 participants were included. The researchers extracted information on various aspects of the studies, such as number of sessions, treatment duration, total contact time, and number of sessions per week. They also assessed the risk of bias in included studies using the Cochrane risk of bias assessment tool.
The researchers found no significant relationship between the number of psychotherapy sessions or total duration of contact with the therapist and treatment effectiveness. This suggests that simply increasing the number of sessions or time spent with a therapist does not necessarily lead to better results.
There was a slight negative association between treatment duration and effect size, indicating that longer treatment duration was marginally related to lower effectiveness. Specifically, each additional week of treatment was associated with a 0.014 decrease in effect size.
But a strong positive association was found between the number of sessions per week and treatment effectiveness. Increasing the frequency from one to two sessions per week was associated with a significant improvement in outcomes, with an increase in effect size of 0.596. This suggests that it is more beneficial to hold sessions more frequently over a shorter period than to spread them out over a longer period.
“It appears that the amount of psychotherapy, whether measured in number of sessions, length of therapy in weeks, or minutes spent with the therapist, is not associated with treatment effects,” Ciharova told PsyPost . “What seems important is rather the frequency of the sessions: the more frequent they are, the better the results.
“However, this association was no longer significant when study characteristics were taken into account. Thus, we suggest that psychotherapy be planned for as short a period as possible. Only if necessary for content-related reasons, more sessions should be held, but as frequently and over as short a period as possible.
“We did not expect the association between session frequency and treatment effects to become insignificant when study characteristics are taken into account,” Ciharova explained. “This did not occur in the previous meta-analysis of which the current study was an update (Cuijpers et al., 2013), and it also contradicts the results of a previous randomized controlled trial (Bruijniks et al ., 2020).”
However, it is important to note that the analysis is observational and cannot establish causality. “While the current study certainly provides some insight into relationships, the results are only correlational,” Ciharova noted. “The reporting of the included studies was also not optimal, so that sometimes the information necessary for the analysis was missing. The methodological quality of the included studies also varied.
Future research should focus on conducting large, high-quality trials to directly compare the effects of different frequencies and amounts of psychotherapy. “The reservations of the current study should be addressed by a large, high-quality randomized controlled trial,” Ciharova said. “Such a trial should also assess how symptoms develop during treatment, another aspect we were unable to address in the present study. Further investigation is needed in other psychotherapy formats, as we only evaluated individual face-to-face psychotherapy.
The study titled “Amount and frequency of psychotherapy as predictors of treatment outcomes for depression in adults: a meta-regression analysis” was authored by Marketa Ciharova, Eirini Karyotaki, Clara Miguel, Esther Walsh, Nino de Ponti, Arpana Amarnath, Wouter van Ballegooijen. , Heleen Riper Bruce Arroll and Pim Cuijpers.