For over 50 years, more than 950 randomised controlled trials have explored the impact of psychological treatment on depression. This extensive research has provided valuable insight into the effectiveness of these treatments across different age groups, target populations, and settings. However, there are still critical questions that remain unanswered.
In the past 15 years, a series of over 100 meta-analyses have been conducted on psychological treatments, resulting in a broad living systematic review known as ‘meta-analytic research domains’ (MARDs). These MARDs provide a comprehensive overview of the field and can be accessed for free at www.metapsy.org. The research has shown that various types of psychological treatments such as cognitive behaviour therapy, interpersonal psychotherapy, and problem-solving therapy are effective compared to other control groups. The effects are small to moderate and can last up to one year after treatment.
These therapies can be delivered through individual sessions, in groups, by telephone, digitally, or in other guided self-help formats. Human support is crucial for their effectiveness. It has been observed that the number of sessions or total contact time does not significantly affect the size of the effects, but more sessions per week lead to larger effects.
One significant finding is that psychotherapies are effective across all adult age groups, but less effective in children and adolescents. However, they have comparable effects in different target groups and care settings. Many trials on psychological treatments suffer from methodological problems, including risk of bias and publication bias, which can affect the reliability of their findings.
In comparison to antidepressant drugs, the effects of psychotherapy are similar in the short term but may be more effective in the long term. It has also been noted that a combination of therapy and medication is more effective than either therapy or medication alone.
Unfortunately, almost 60% of those who receive treatment for depression do not respond, indicating that there is room for improvement in the effectiveness of these therapies. More research on sequential treatments is needed to determine which therapy is best for individual patients and when and why specific treatments should be initiated. Ultimately, the goal is to improve the outcomes of psychological treatments for depression.
