What’s the ‘optimal dose’ of psychotherapy to improve social functioning in people with depression?


The majority of studies about depression measure outcomes using a scale such as the Hamilton Depression Rating Scale (PDF), which is a questionnaire that patients complete with a health professional.

This new randomised controlled trial by researchers from the Arkin Institute for Mental Health in Amsterdam uses the Hamilton Depression Scale, but is also measures social functioning, which is clearly a key component of any recovery from depression.  They use the Groningen Social Disability Schedule (ref 2) to measure social functioning in patients with depression who are given antidepressants and 8 or 16 sessions of short psychodynamic supportive psychotherapy.

The aim of the study was to identify the ‘optimal dose’ of psychotherapy for patients with major depression who are not responding to treatment with antidepressants alone.


They randomised 463 people with major depression to receive one of these two possible treatments:

  • Antidepressants and 8 weekly psychotherapy sessions
  • Antidepressants and 16 psychotherapy sessions (8 weekly psychotherapy sessions, followed by 8 fortnightly psychotherapy sessions)

The psychotherapy sessions were 45-min sessions of short psychodynamic supportive psychotherapy.

Exclusion criteria

Patients were excluded if they had:

  • Responded to antidepressants during the present depressive episode
  • A medical condition that had caused their mental health condition
  • Substance abuse issues
  • Psychosis and/or dissociative disorder
  • Used psychotropic medication other than that prescribed in the study
  • Problems with communication
  • Recently become pregnant or were trying for a baby
  • Been assessed as ‘too suicidal’, ‘too ill’ or not reliable to participate

Study shortcomings

  • The trial did not report allocation concealment.
  • Trial assessors were blinded to the Hamilton Scale depression scores, but all other outcomes were unblinded.
  • There was a significant drop-out rate with 65.3% of patients completing the eight sessions of psychotherapy and 55.6% completing the 16 sessions.


Here’s what they found:

  • Social functioning improved by week 20 of the study
  • However, there was no significant difference in social functioning between 8 and 16 sessions of psychotherapy


The authors concluded:

At the end of treatment, no clear differences are found between 8 or 16 sessions of psychotherapy (both combined with pharmacotherapy) with regard to severity of depression and social functioning. It is thus still unknown if patients with major depression show more improvement in social functioning and less symptoms of depression after 16 sessions of combined therapy than after 8 sessions. Currently, it seems that for major depression 8 sessions of combined therapy are equally effective as 16 sessions.


  1. Molenaar PJ, Boom Y, Peen J, Schoevers RA, Van R, Dekker JJ. Is there a dose-effect relationship between the number of psychotherapy sessions and improvement of social functioning? Br J Clin Psychol. 2011 Sep;50(3):268-82. doi:10.1348/014466510X516975. Epub 2011 Mar 8. [PubMed abstract]
  2. Wiersma D, DeJong A, Ormel J. The Groningen Social Disabilities Schedule: development, relationship with I.C.I.D.H., and psychometric properties. Int J Rehabil Res. 1988;11(3):213-24. [PubMed abstract]
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Andre Tomlin

André Tomlin is an Information Scientist with 20 years experience working in evidence-based healthcare. He's worked in the NHS, for Oxford University and since 2002 as Managing Director of Minervation Ltd, a consultancy company who do clever digital stuff for charities, universities and the public sector. Most recently André has been the driving force behind the Mental Elf and the National Elf Service; an innovative digital platform that helps professionals keep up to date with simple, clear and engaging summaries of evidence-based research. André is a Trustee at the Centre for Mental Health and an Honorary Research Fellow at University College London Division of Psychiatry. He lives in Bristol, surrounded by dogs, elflings and lots of woodland!

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