Abstract
Purpose
Social support is important for maintaining and restoring psychological well-being but the effects of individual psychotherapies on perceived social support are not well known. In this analysis of secondary outcomes from a randomized clinical study, we compared the effects of long-term psychotherapy and two short-term psychotherapies on social support during a 5-year follow-up.
Materials and methods
Altogether 326 adult outpatients suffering from depressive and/or anxiety disorders were randomly assigned to long-term psychodynamic psychotherapy (LPP, n = 126), short-term psychodynamic psychotherapy (SPP, n = 101) and solution-focused therapy (SFT, n = 97). Outcome was measured by the global index and six subscores of the self-reported Brief Inventory of Social Support and Integration scale (BISSI) at baseline and at 1, 2, 3, 4 and 5 years after the beginning of the therapy.
Results
Social support improved in all therapy groups and the improvement was relatively stable, lasting several years after the end of therapy. Little difference in improvement was observed either between therapy orientations or durations.
Conclusions
While no major differences were observed between treatment groups, the slight differences call for further research to verify these findings and to better understand how different therapies may improve perceived social support.
1. Introduction
Social support has a crucial role for individuals’ psychological well-being [Citation1–3]. Good social relationships meet essential needs of people through providing empathy, warmth, validation, advice, and attachment [Citation4], and integration in social networks promotes positive experiences such as belonging, security and self-worth [Citation5]. Sustained by the interactions between individuals and their social networks, the perceived availability and quality of social support extends one’s personal resources and decreases negative affectivity and life stress [Citation6]. Thus, good social support also buffers responses to stressful events [Citation5] and decreases the risk for depressive [Citation7,Citation8] and anxiety disorders [Citation9,Citation10], being therefore especially important for people otherwise at risk for these disorders.
Various psychotherapies have been shown effective for treating depressive and anxiety disorders [Citation11]. In addition to relieving psychiatric symptoms and improving functioning, psychotherapy can help patients also to better utilize available social support as well as broaden their positive social networks [Citation12,Citation13]. Despite its importance for well-being, social support is nevertheless relatively neglected when evaluating the outcomes of psychotherapies for people suffering from mental disorders [Citation14].
In a meta-analysis of 11 clinical trials, brief psychotherapies for adult depression were found to have usually a small to moderate, yet consistent positive effect on social support at post-treatment and up to 1-year follow-up when compared to care-as-usual or no care at all [Citation8]. Most studies examined group interventions, representing typically a cognitive–behavioral (CBT) approach, and focusing on specific populations, e.g. persons with medical conditions or postpartum depression. Two studies on other brief group psychotherapies – representing interpersonal [Citation15] and counseling [Citation16] approaches – and seeking to specifically advance social support, indicated moderate between-group effect sizes and showed perceived social support to improve more in the active intervention vs. in care as usual. In addition, a study on short-term interpretive and supportive psychodynamic group therapies showed increases in both treatment approaches in perceived social support from family, friends, and a special person during the follow-up but not during the treatment [Citation17].
Studies on the effectiveness of individual brief therapies on social support are scarce but the findings from a few studies show similar effects as in group therapies [Citation8]. However, to the best of our knowledge, there is only one prior study examining how social support may be impacted by both the theoretical form as well as the duration of therapy. In a prospective, quasi-experimental study with patients suffering from depression, perceived social support was improved during the course of individual medium-length CBT as well as long-term psychodynamic and psychoanalytic therapy. No significant differences between the therapies were found at any point during treatment [Citation18,Citation19]. However, the improvement continued only after the end of the psychoanalytic therapy, until a 3-year follow-up, and was consequently greater than in the two other therapies. Apart from this study, none of the follow-ups have lasted more than one year.
Accordingly, one of the secondary aims of this randomized effectiveness study was to examine whether the changes in perceived social support in adult patients suffering from depressive and/or anxiety disorders differ between three different individual psychotherapy approaches (long-term psychodynamic psychotherapy (LPP), short-term psychodynamic psychotherapy (SPP) and short-term solution-focused therapy (SFT)) during a five-year follow-up time from the start of the therapy [Citation20]. The first, a priori hypothesis, as also supported by more recent findings from Huber and colleagues [Citation18], was that improvement in social support would in the long term be greater in LPP than in both of the short-term therapies [Citation20]. Further, our second, post hoc hypothesis was that as SFT shares some of the goals and posited mechanisms of other therapies shown more recently to have a relatively good positive effect on social support [Citation15,Citation16,Citation21,Citation22], social support would improve more in SFT than in SPP.
2. Subjects and methods
2.1. Patients and setting
This study was carried out as an analysis of secondary outcomes from the Helsinki Psychotherapy Study (HPS), a randomized clinical trial comparing the effectiveness of three psychotherapy approaches in the treatment of psychiatric outpatients. Patients and methods of the HPS have been described in detail elsewhere [Citation20,Citation23] and are reported only briefly here. The patients gave written informed consent and the Helsinki University Ethics Council approved the study.
The criteria the patients were required to satisfy included being 20–45 years of age, psychiatric outpatients suffering from long-standing (>1 year) work dysfunction [Citation20]. The disorder had to meet the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) criteria [Citation24] for an anxiety and/or mood disorder. Exclusion criteria consisted of psychotic, substance abuse, severe personality disorder, adjustment disorder, organic brain disease or other severe organic disease, having attended psychotherapy during previous two years, working in mental health profession or having personal ties with a member of the research group [Citation20]. The primary outcome of interest were psychiatric symptoms, especially those related to depressive and anxiety disorders (ibid.).
Of the 459 recruited patients, 133 refused to participate. The altogether 326 remaining participants were randomly assigned to solution-focused psychotherapy (SFT, 97 patients), short-term psychodynamic psychotherapy (SPP, 101 patients) and long-term psychodynamic psychotherapy (LPP, 128 patients) [Citation23]. After the randomization a total of 33 patients (4 in the SFT, 3 in the SPP and 26 in the LPP group) decided to refuse their participation. Altogether 42 patients discontinued their treatment prematurely (11 in SFT, 10 in SPP, and 21 in LPP). The mean (SD) numbers of completed therapy sessions were 9.8 (3.3) in SFT, 18.5 (3.4) in SPP and 232 (105) in LPP.
2.2. Therapies and therapists
SFT is a goal-focused form of brief therapy in which the aim is to recognize the patient’s main problems and find solutions to them [Citation25,Citation26]. Using patient’s own resources, home assignments and positive feedback as central components, solution-focused therapies were conducted flexibly with a maximum of 12 sessions, once in two or three weeks [Citation20]. SPP is a brief, focal and transference-based therapy approach developed by Malan [Citation27] and Sifneos [Citation28]. Therapy focused on working out specific current and past intrapsychic and interpersonal conflicts and it was conducted as a 20-session, once-a-week intervention [Citation20]. LPP is an open-ended, intensive and transference-based therapeutic approach [Citation29]. Working on a broad area of current and past intrapsychic and interpersonal conflicts, LPP was conducted with 2–3 weekly sessions up to a maximum time of 3 years [Citation20].
A total of 55 qualified therapists conducted the therapies, with 6 giving SFT, 12 SPP and 41 LPP [Citation30]. The mean experience of therapists providing SFT and SPP was 9 years (ranges 3–15 and 2–20 years, respectively) and 18 years (range 6–30 years) in therapists providing LPP.
2.3. Assessments
The assessment methods are described in more detail elsewhere [Citation20,Citation31] and are only briefly summarized here. The assessments were conducted at baseline and the social support measure (one of the secondary outcome measures and this study’s primary outcome indicator) was repeated at 1, 2, 3, 4 and 5 years after the beginning of the therapy.
A brief inventory of social support and integration (BISSI) was used to assess the outcome, i.e. the level of social support [Citation31]. The BISSI is a 13-item self-reported questionnaire developed for measuring the amount of social support an individual perceives. BISSI contains five subscales (social network size, satisfaction in social support and relations, perceived availability of emotional support from family, perceived availability of emotional support from friends and perceived availability of emotional support from professionals), summed up for the global index. The size of social network was assessed using a 6-point scale, ranging from 0 (no close friends) to 5 (five or more close friends). Satisfaction in social support and social relations was assessed by 2 items using a 5-point scale, with combined scores ranging from 2 (very unsatisfied) to 10 (very satisfied). Perceived availability of emotional support from family (4 items), friends (3 items) and professionals (2 items) were evaluated on 4-point scales. The scores of each subscale were summed, with ranges varying from 4 to 16 (family), 3 to 12 (friends) and 2 to 8 (professionals), higher scores indicating better perceived support. In addition, scores of perceived availability of support subscales were combined and transformed into a scale from 0 (not at all) to 5 (very much) for forming a global index. The global index, which was used as the primary outcome indicator, was created as the sum of the network size and satisfaction subscales and the combined perceived availability of support score, ranging therefore from 2 (very low level of support) to 20 (very high level of support).
Sociodemographic information including age, sex, marital status, education and employment status and psychiatric history data (duration of primary disorder and previous psychiatric treatment) were gathered at baseline from questionnaires, interviews and national registers. In addition, depressive and anxiety symptoms were assessed by the self-rated Hamilton Depression Rating Scale (HDRS) [Citation32] and Hamilton Anxiety Rating Scale (HARS) [Citation33] and psychiatric diagnoses (DSM-IV) [Citation24] by interview. The interviews were conducted by experienced clinical raters [Citation34]. Information on the external quality of the study treatment (duration of therapy, frequency and number of sessions, unusual breaks, change of therapist), discontinuation of study treatment during follow-up, and use of auxiliary psychiatric treatment (psychotropic medication, additional psychotherapy, and psychiatric hospitalization) was collected throughout the follow-up via questionnaires, interviews and national registers [Citation35].
2.4. Statistical methods
The study was executed as a randomized clinical trial with repeated measurements. The main analyses on the effectiveness of psychotherapies on social support were based on the “intention-to-treat” (ITT) sample including all the randomized patients as outlined in the original analysis plan [Citation20]. Ignorable drop-outs were assumed in the main analyses [Citation36]. The statistical analyses were based on linear mixed models [Citation37]. BISSI and all its subscales were used as the dependent variables in separate analyses, the global score being the primary outcome indicator. The main effects of therapy group, follow-up time, the difference between theoretical and realized date of measurement, and first-order interaction of therapy group and time were the independent variables in the model. A completed model further adjusted for the baseline level of each outcome measure. Model-adjusted mean levels and mean differences of the outcome measures between the therapy groups were calculated for all the measurement points using predictive margins [Citation38,Citation39]. The confidence intervals were calculated using the delta method [Citation40]. The Wald test was used to calculate the statistical significance. Complementary” as-treated” (AT) analyses were performed by further including variables on possible violation of the treatment standards, i.e. waiting time from baseline examination to start of study treatment, participation after randomization, discontinuation of the study treatment (drop-outs), external quality of the study treatment, and the use of auxiliary psychiatric treatment (i.e. psychotherapy, psychiatric medication, and psychiatric hospitalization) during follow-up as main effects in the models. As only slight differences between the results of the models were found, the results of the ITT model were displayed as main results. All the statistical analyses were performed using the SAS software, version 9.3 [Citation41].
3. Results
3.1. Baseline characteristics
The patients were relatively young and more than three quarters of the patients were women (). About half of the patients were cohabiting or married at the baseline, a quarter had an academic education; and four out of five patients were either working or studying. Over 80% of the patients suffered from mood disorder and less than a half from anxiety disorder. The patients reported having on average about four close friends at baseline. They were, on average, neither satisfied nor dissatisfied with their social support with a mean score of 6.5 on a scale from 2 to 10.
Table 1. Baseline characteristics of the patients by treatment group [Citation20, Citation31].
3.2. Treatment effects
On the primary indicator, the BISSI global index, no statistically significant between-group differences were observed through the entire 5-year follow-up (). However, in the AT model, more improvement was observed in the LPP vs. SPP group at the 1-year and 3-year follow-ups (Appendix A): the improvement from baseline to 3-year follow-up being 15% and 8%, in the two treatment groups, respectively. By the final follow-up at 5 years, the change percentages were 15%, 12% and 7% in LPP, SFT and SPP, respectively.
Table 2. Mean score levels and standard errors of BISSI global index in treatment groups and adjusted mean score differences (95% confidence intervals) between treatment groups at annual follow-up points.
On all the BISSI subscales (), with the exception of the size of the social network, statistically significant improvement was found throughout most of the follow-up in all therapy groups. In the BISSI subscales, several statistically significant differences between the therapy groups were found, mostly in favor of LPP over SPP. Satisfaction in social support had increased more in LPP than SPP at 1-year and also at the final 5-year follow-up. Likewise, more improvement in LPP than SPP was found in the availability of social support from professionals at 1- and 2-year follow-ups, with a similar difference between LPP and SFT in the AT model (Appendix B). At the 3-year follow-up, statistically significantly greater increase in perceived availability of support from friends was found in LPP than SPP. Differences between the short-term therapy groups were minimal and not statistically significant after Bonferroni correction of statistical significance.
Table 3. Mean score levels and standard errors of BISSI subscales in treatment groups and adjusted mean score differences (95% confidence intervals) between treatment groups at annual follow-up points.
4. Discussion
4.1. Main findings
To the best of our knowledge, this is the first randomized study to compare the effects of short- vs. long-term individual psychotherapy, representing two distinctly different theoretical approaches, on perceived social support in patients with depressive or anxiety disorder. Perceived social support and most of its subdimensions improved in all three therapies, in line with expectations and findings from prior research [Citation8,Citation18]. This supports the conclusion that various kinds of therapies may have a positive effect on perceived social support even if it is not the main treatment objective; however, it is also possible that some spontaneous remission occurs in perceived social support even if one does not receive psychotherapy, similar to the remission commonly observed in depressive symptoms [Citation42]. Yet among the novel findings of this study, we showed that neither the treatment duration nor the theoretical approach of therapy appeared to make great difference for the observed changes in social support – even if greater symptomatic recovery has typically been observed in long-term over short-term therapies [Citation43,Citation44].
To discuss the few consistent differences between treatment groups that did emerge, it should first be noted that the availability of perceived professional support was expectably greater in LPP than in both SPP and SFT, given LPP’s greater intensity and duration. Beyond that, the most noticeable finding was the superiority of LPP over SPP which emerged at different phases of the follow-up in the AT models and in the social support subscales (i.e. network size, availability of support from friends, and satisfaction in support). As to the explanations why a longer psychodynamic treatment could yield the observed benefits over a shorter one, several possibilities exist which are not mutually exclusive. First, given its longer time frame, LPP perhaps allows the patient to more thoroughly process the intrapsychic and interpersonal conflicts that negatively impact his or her social functioning and availing oneself of social support, e.g. through observing, reflecting on, and changing one’s behavior [Citation29,Citation45]. Secondly, while SPP also utilizes the same transference- and relationship-focused techniques as LPP [Citation46,Citation47], LPP’s more intense therapeutic relationship – in both its supportive and explorative aspects – has been suggested to better enable understanding and modifying social behaviors [Citation48]. Third, it is also possible that the long-term therapeutic relationship in itself provides a “corrective emotional experience” [Citation49] that leads not necessarily to a change in social behavior or networks but rather in how they are experienced: e.g. that friends are perceived as more numerous, caring, and responsive than before. Such an explanation is indirectly supported by a previous finding from the HPS, indicating that patients with more pre-treatment interpersonal problems actually experienced better therapeutic working relationships at the end of LPP than patients with less interpersonal problems. This suggests that stereotypically negative experiences and expectations of other people can paradoxically turn into experiencing better (therapeutic) relationships, given a long and presumably empathic and validating connection [Citation50]. Nevertheless, the differences between LPP and SPP being relatively few and small, the overall conclusion is that long-term therapy has perhaps less ability to improve a person’s social network over short-term therapy than, for example, symptomatic or personality functioning [Citation23,Citation44,Citation51]. This conclusion is further underlined by the total BISSI scores in LPP being expectably elevated by greater perceived professional support, as compared to both short-term therapies.
In contrast to the few differences between LPP and SPP, virtually no meaningful differences between SFT and LPP were observed. As the average treatment length, frequency, and number of sessions in SFT was either comparable or lesser than in SPP, this gives slight support for the suggestion that dosage alone does not account for changes in social support but other aspects may also matter. Indeed, it would not seem surprising that the characteristic aim of SFT to deliberately mobilize and utilize the patient’s family and other current relationships as already existing strengths would make a difference [Citation22,Citation25]; and that SFTs focus on solutions rather than problems, including the role of family and friends, could create a virtuous cycle leading to greater actual and perceived social support [Citation4].
Regardless, it should be noted that very few direct differences were observed between SFT and SPP. The only minor differences appeared in slightly faster rate of improvement in SFT in the BISSI subscales of satisfaction with support and support from family during the 1- and 2-year follow-ups, respectively. There are no previous studies comparing these two short-term treatments on perceived social support, but the present findings suggest any differences are relatively small. The results also align with findings on numerous other brief therapies, showing typically non-significant differences in effect sizes between treatments, with only a tendency of greater benefits in those therapies that specifically seek to advance social support [Citation8]. The frequent and long-standing explanation for such lack of differences between therapies has been that of their shared “common factors” (e.g. a confiding, empathic, emotionally evocative relationship with a therapist, offering an explanation for the client’s problems, and so on) [Citation52,Citation53]. These common factors are presumed to contribute to a general remoralization of the patient – one aspect of which could indeed be a more optimistic perception of social support.
4.2. Methodological considerations
Strengths and limitations of the HPS study have been discussed in much detail in prior publications [Citation20,Citation43] and will be dealt with here relatively briefly. First, the effectiveness of different short-term psychotherapeutic approaches in a face-to-face comparison and vis-à-vis long-term psychotherapy on perceived social support has not been carried out previously in a randomized clinical trial. Second, the follow-up period was several years longer than in most previous studies, including regular annual measurements. Third, for external validity, the psychodynamic therapies were conducted as in normal clinical practice without separate arrangements (i.e. use of manualized protocols or protocol-based supervision) and in solution-focused therapy according to standards of the respective therapy center (i.e. with centralized supervision and monitoring). Fourth, all psychotherapists were trained, qualified, and well-experienced for providing the treatments in question. Fifth, the sample size of the study was relatively large, consisting of adult outpatients with depressive and anxiety disorders, i.e. those most usually treated by individual short- and long-term psychotherapies, excluding only patients suffering from severe personality disorders. Thus, it provides relatively well generalizable results.
Several limitations have to also be taken into account when interpreting the results of this study. First, a non-treatment control group was not included in the study due to ethical reasons, considering the exceptionally long follow-up time. Second, as the patients were randomized into therapies, the individual acceptability and suitability of the therapies for the patients was not able to be taken into account. This may have affected the moderate refusal rate of patients after the randomization especially in the LPP group, thus creating bias in the different therapy groups. However, no statistically significant differences were noted in the baseline characteristics of the patients between the groups [Citation20]. Third, in addition, use of auxiliary treatment was rather frequent, especially in the short-term therapy groups [Citation35]. Nevertheless, considering both the second and third points above, participation after randomization and use of auxiliary treatment were included in the AT analyses, which generally showed no notable differences in comparison to the ITT findings. Fourth and finally, as patients suffering from severe personality disorders were excluded from the study, the results are not generalizable to this patient group.
4.3. Conclusion
In conclusion, widening the evidence-base of prior studies, this analysis of secondary outcomes of a randomized clinical trial for treating depressive and anxiety disorders found social support experienced by patients to increase after short- and long-term psychodynamic psychotherapy and solution-focused therapy. The exceptionally long follow-up of the study also indicated these gains to be markedly stable, enduring several years after the therapies ended. While no major differences between the therapy groups were observed, slight differences in favor of LPP over SPP were found until the end of long-term therapy. As social support and connection are central determinants of people’s wellbeing, further research is needed to better understand the mechanisms underlying the observed differences and how different therapies may improve perceived social support.
Supplemental Material
Download MS Word (29.7 KB)Acknowledgements
We would like to thank Julius Rissanen for his assistance in statistical analyses for this article.
Disclosure statement
The authors declare no conflict of interest.
Data availability statement
The dataset cannot be publicly shared due to data protection issues (sensitive personal data).
References
- Cohen S, Wills TA. Stress, social support, and the buffering hypothesis. Psychol Bull. 1985;98(2):310–357.
- Powdthavee N. Putting a price tag on friends, relatives, and neighbours: using surveys of life satisfaction to value social relationships. J Socio-Econ. 2008;37(4):1459–1480. doi: 10.1016/j.socec.2007.04.004.
- Thoits PA. Stress, coping and social support processes: where are we? What next? J Health Soc Behav. 1995;35:53–79. doi: 10.2307/2626957.
- Roehrle B, Strouse J. Influence of social support on success of therapeutic interventions: a meta-analytic review. Psychotherapy (Chic). 2008;45(4):464–476. doi: 10.1037/a0014333.
- Kawachi I, Berkman LF. Social ties and mental health. J Urban Health. 2001;78(3):458–467. doi: 10.1093/jurban/78.3.458.
- Pocnet C, Antonietti J-P, Strippoli M-PF, et al. Individuals’ quality of life linked to major life events, perceived social support, and personality traits. Q Life Res. 2016;25(11):2897–2908. doi: 10.1007/s11136-016-1296-4.
- Leskelä U, Rytsälä H, Komulainen E, et al. The influence of adversity and perceived social support on the outcome of major depressive disorder in subjects with different levels of depressive symptoms. Psychol Med. 2006;36(6):779–788. doi: 10.1017/S0033291706007276.
- Park M, Cuijpers P, van Straten A, et al. The effects of psychotherapy for adult depression on social support: a meta-analysis. Cognit Ther Res. 2014;38(6):600–611. doi: 10.1007/s10608-014-9630-z.
- Plaisier I, de Bruijn JGM, de Graaf R, et al. The contribution of working conditions and social support to the onset of depressive and anxiety disorders among male and female employees. Soc Sci Med. 2007;64(2):401–410. doi: 10.1016/j.socscimed.2006.09.008.
- Wang J, Mann F, Lloyd-Evans B, et al. Associations between loneliness and perceived social support and outcomes of mental health problems: a systematic review. BMC Psychiatry. 2018;18(1):156 (article 156). doi: 10.1186/s12888-018-1736-5.
- Cuijpers P, van Straten A, Andersson G, et al. Psychotherapy for depression in adults: a meta-analysis of comparative outcome studies. J Consult Clin Psychol. 2008;76(6):909–922. doi: 10.1037/a0013075.
- Eurelings-Bontekoe EH, Diekstra RF, Verschuur M. Psychological distress, social support and social support seeking: a prospective study among primary mental health care patients. Soc Sci Med. 1995;40(8):1083–1089. doi: 10.1016/0277-9536(94)00182-s.
- Ogrodniczuk JS, Piper WE, Joyce AS, et al. Social support as a predictor of response to group therapy for complicated grief. Psychiatry. 2002;65(4):346–357. doi: 10.1521/psyc.65.4.346.20236.
- Cuijpers P. Targets and outcomes of psychotherapies for mental disorders: an overview. World Psychiatry. 2019;18(3):276–285. doi: 10.1002/wps.20661.
- Mulcahy R, Reay RE, Wilkinson RB, et al. A randomised control trial for the effectiveness of group interpersonal psychotherapy for postnatal depression. Arch Womens Ment Health. 2010;13(2):125–139. doi: 10.1007/s00737-009-0101-6.
- Chen C-H, Tseng Y-F, Chou F-H, et al. Effects of support group intervention in postnatally distressed women: a controlled study in Taiwan. J Psychosom Res. 2000;49(6):395–399. doi: 10.1016/s0022-3999(00)00180-x.
- Ogrodniczuk JS, Joyce AS, Piper WE. Changes in perceived social support after group therapy for complicated grief. J Nerv Ment Dis. 2003;191(8):524–530. doi: 10.1097/01.nmd.0000082180.09023.64.
- Huber D, Zimmermann J, Henrich G, et al. Comparison of cognitive-behaviour therapy with psychoanalytic and psychodynamic therapy for depressed patients: a three-year follow-up study. Z Psychosom Med Psychother. 2012;58(3):299–316. doi: 10.13109/zptm.2012.58.3.299.
- Huber D, Henrich G, Clarkin J, et al. Psychoanalytic versus psychodynamic therapy for depression: A three-year follow-UP study. Psychiatry. 2013;76(2):132–149. doi: 10.1521/psyc.2013.76.2.132.
- Knekt P, Lindfors O, editors. A randomized trial of the effect of four forms of psychotherapy on depressive and anxiety disorders. Design, methods, and results on the effectiveness of short-term psychodynamic psychotherapy and solution-focused therapy during a one-year follow-up. Studies in social security and health. Helsinki: the Social Insurance Institution; 2004. https://www.thl.fi/attachments/HPS/HPS_effectiveness.pdf. Accessed online 5.12.2023.
- Lipsitz JD, Markowitz JC. Mechanisms of change in interpersonal therapy (IPT). Clin Psychol Rev. 2013;33(8):1134–1147. doi: 10.1016/j.cpr.2013.09.002.
- Priebe S, Omer S, Giacco D, et al. Resource-oriented therapeutic models in psychiatry: conceptual review. Br J Psychiatry. 2014;204(4):256–261. doi: 10.1192/bjp.bp.113.135038.
- Knekt P, Lindfors O, Sares-Jäske L, et al. Randomized trial on the effectiveness of long- and short-term psychotherapy on psychiatric symptoms and working ability during a 5-year follow-up. Nord J Psychiatry. 2013;67(1):59–68. doi: 10.3109/08039488.2012.680910.
- American Psychiatric Association. Diagnostic and statistic manual of mental disorders. Washington, DC: American Psychiatric Association; 1994.
- de Shazer S, Berg IK, Lipchik E, et al. Brief therapy: focused solution development. Fam Process. 1986;25(2):207–221. doi: 10.1111/j.1545-5300.1986.00207.x.
- Johnson LD, Miller SD. Modification of depression risk factors: a solution-focused approach. Psychotherapy. 1994;31(2):244–253. doi: 10.1037/h0090220.
- Malan DH. The frontier of brief psychotherapy: an example of the convergence of research and clinical practice. New York: Plenum Medical Book; 1976.
- Sifneos PE. Short-term anxiety provoking psychotherapy. In Davanloo H, editor. Short-term dynamic psychotherapy. New York: Spectrum; 1978. p. 35–42.
- Gabbard GO. Long-term psychodynamic psychotherapy: a basic text. Washington DC: American Psychiatric Association Publishing; 2004.
- Heinonen E, Lindfors O, Laaksonen MA, et al. Therapists’ professional and personal characteristics as predictors of outcome in short- and long-term psychotherapy. J Affect Disord. 2012;138(3):301–312. doi: 10.1016/j.jad.2012.01.023.
- Lindfors O, Ojanen S, Jääskeläinen T, et al. Social support as a predictor of the outcome of depressive and anxiety disorder in short-term and long-term psychotherapy. Psychiatry Res. 2014;216(1):44–51. doi: 10.1016/j.psychres.2013.12.050.
- Hamilton M. A rating scale for depression. J Neurol Neurosurg Psychiatry. 1960;23(1):56–62. doi: 10.1136/jnnp.23.1.56.
- Hamilton M. The assessment of anxiety states by rating. Br J Med Psychol. 1959;32(1):50–55. doi: 10.1111/j.2044-8341.1959.tb00467.x.
- Laaksonen MA, Lindfors O, Knekt P, et al. Suitability for psychotherapy scale (SPS) and its reliability, validity, and prediction. Br J Clin Psychol. 2012;51(4):351–375. doi: 10.1111/j.2044-8260.2012.02033.x.
- Knekt P, Lindfors O, Renlund C, et al. Use of auxiliary psychiatric treatment during a 5-year follow-up among patients receiving short- or long-term psychotherapy. J Affect Disord. 2011;135(1-3):221–230. doi: 10.1016/j.jad.2011.07.024.
- Härkänen T, Knekt P, Virtala E, et al. A case study in comparing therapies involving informative drop-out, non-ignorable non-compliance and repeated measurements. Stat Med. 2005;24(24):3773–3787. doi: 10.1002/sim.2409.
- Verbeke G, Molenberghs G. Linear mixed models in practice: a SAS-oriented approach. New York: Springer; 1997.
- Graubard BJ, Korn EL. Predictive margins with survey data. Biometrics. 1999;55(2):652–659. doi: 10.1111/j.0006-341x.1999.00652.x.
- Lee J. Covariance adjustment of rates based on the multiple logistic regression model. J Chronic Dis. 1981;34(8):415–426. doi: 10.1016/0021-9681(81)90040-0.
- Migon HS, Gamerman D. Statistical inference: an integrated approach. London: Arnold; 1999.
- SAS Institute Inc. SAS online doc. SAS/STAT user’s guide, version 9. Cary: SAS Institute Inc; 2011.
- Whiteford HA, Harris MG, McKeon G, et al. Estimating remission from untreated major depression: a systematic review and meta-analysis. Psychol Med. 2013;43(8):1569–1585. doi: 10.1017/S0033291712001717.
- Knekt P, Lindfors O, Härkänen T, et al. Randomized trial on the effectiveness of long-term and short-term psychodynamic psychotherapy and solution-focused therapy on psychiatric symptoms during a 3-year follow-up. Psychol Med. 2008;38(5):689–703. doi: 10.1017/S003329170700164X.
- Leichsenring F, Rabung S. Long-term psychodynamic psychotherapy in complex mental disorders: update of a meta-analysis. Br J Psychiatry. 2011;199(1):15–22. doi: 10.1192/bjp.bp.110.082776.
- Zimmermann J, Löffler-Statska H, Huber D, et al. Is it all about the higher dose? Why psychoanalytic therapy is an effective treatment for major depression. Clin Psychol Psychother. 2015;22(6):469–487. doi: 10.1002/cpp.1917.
- Bond M, Perry JC. Long-term changes in defense styles with psychodynamic psychotherapy for depressive, anxiety, and personality disorders. Am J Psychiatry. 2004;161(9):1665–1671. doi: 10.1176/appi.ajp.161.9.1665.
- Mullin ASJ, Hilsenroth MJ, Gold J, et al. Changes in object relations over the course of psychodynamic psychotherapy. Clin Psychol Psychother. 2016;24(2):501–511. doi: 10.1002/cpp.2021.
- Shedler J. The efficacy of psychodynamic psychotherapy. Am Psychol. 2010;65(2):98–109. doi: 10.1037/a0018378.
- Christian C, Safran JD, Muran JC. The corrective emotional experience: a relational perspective and critique. In Castonguay LG, Hill CE, editors. Transformation in psychotherapy: corrective experiences across cognitive behavioral, humanistic, and psychodynamic approaches. Washington, DC: American Psychological Association; 2012. p. 51–67.
- Ollila P, Knekt P, Heinonen E, et al. Patients’ pre-treatment interpersonal problems as predictors of therapeutic alliance in long-term psychodynamic psychotherapy. Psychiatry Res. 2016;241:110–117. doi: 10.1016/j.psychres.2016.04.093.
- Lindfors O, Knekt P, Heinonen E, Helsinki Psychotherapy Study Group., et al. The effectiveness of short-and long-term psychotherapy on personality functioning during a 5-year follow-up. J Affect Disord. 2015;173:31–38. doi: 10.1016/j.jad.2014.10.039.
- Cuijpers P, Reijnders M, Huibers MJ. The role of common factors in psychotherapy outcomes. Annu Rev Clin Psychol. 2019;15(1):207–231. doi: 10.1146/annurev-clinpsy-050718-095424.
- Frank JD. Persuasion and healing. A comparative study of psychotherapy. Baltimore, MD: Johns Hopkins Press, 1961.