Psychotherapy as a double-edged sword: how to investigate its negative effects?

Psychotherapy is a widely recognized tool for promoting mental health, and its positive effects are well documented. In recent years, however, professional attention has increasingly turned to its other side – namely, its potential risks and negative effects. Informing patients about potential risks strengthens their trust in the therapist and the entire process, unifies positive expectations, and reduces the rate of psychotherapy discontinuation or dissatisfaction. Furthermore, understanding the negative effects of psychotherapy and unifying their assessment would greatly improve the possible work with these negative effects and contribute to better care for clients in general. A new review article published in the prestigious journal Nature Reviews Psychology, co-authored by Zbyněk Vybíral from INPSY/Center for Psychotherapy Research, reflects the trend in the growth of research on the negative effects of psychotherapy and offers a comprehensive view of what is actually meant by "negative effects."

What exactly are the negative effects of psychotherapy?

The negative effects of psychotherapy are a complex and multi-layered phenomenon, and there is currently no professional consensus on how to clearly define them. They can include both the undesirable consequences of properly conducted therapy (e.g., temporary worsening of symptoms as a side effect of working on difficult issues) and reactions to incorrect therapeutic procedures or direct mistakes made by the therapist. They can be perceived not only by clients, but also by their loved ones or therapists themselves, often in different ways – for example, a client's breakup may be understood by the therapist as a step toward growth, by the partner as a loss, and by the client as an ambivalent experience with short-term relief and later negative impact.

Negative effects can occur at various stages of therapy, even before it begins, and can vary in severity and duration – from mild and temporary to long-term or life-threatening. Their occurrence is influenced by a combination of factors at the social level (stigmatization, cultural attitudes), institutional level (type of intervention, treatment settings), and individual level (characteristics of the client and therapist, quality of the therapeutic relationship, etc.). In addition, the results of psychotherapy often develop gradually through feedback – for example, the patient's initial response to therapy can influence how the therapist proceeds, which in turn shapes the patient's further involvement and progress in treatment.

How can negative effects be measured?

Measuring the negative effects of psychotherapy is relatively complex, as these effects can take many forms and have many sources. In practice, simple and informal procedures are used – for example, when the therapist asks the patient general questions about changes in their life, or when they notice signs of distress during the session – but systematic and structured tools are also used. These include, in particular, questionnaires that patients fill out themselves and that have been specially developed to map negative experiences from therapy. Some tools even combine the assessment of positive and negative effects to avoid bias towards an overly negative picture.

In addition, there are observational methods – such as detailed evaluation of video recordings of therapy sessions – that attempt to distinguish the side effects of properly conducted therapy from the consequences of the therapist's malpractice. However, such evaluations are time-consuming and require expertise. Other options include semi-structured interviews, analysis of medical records, and monitoring of indicators such as premature termination of therapy. In this case, too, it is essential to determine whether the termination was due to a negative experience or, on the contrary, because the patient achieved the desired improvement. Overall, it is necessary to combine various sources of information and the perspectives of multiple actors in order to capture the negative effects of psychotherapy.

How common are negative effects?

Research shows that negative effects of psychotherapy are not uncommon – although serious and life-threatening consequences are rare, milder forms affect a relatively large number of patients. Studies suggest that one in ten patients may experience some kind of adverse effect, with more serious cases (such as the need for hospitalization after a suicide attempt or crisis intervention) occurring in approximately one in twenty-one. The most common are unpleasant memories, stress, anxiety, or feelings of dependence on the therapist, with serious misconduct reported rather rarely.

Research into the negative effects of psychotherapy is still in its infancy, but it is an essential field that helps to better protect patients and improve the quality of care. The authors emphasize the need to standardize terminology, introduce standardized measurement methods, and take greater account of the experiences of patients and therapists throughout the course of therapy. Education is also very important – future therapists should be taught from the outset to recognize negative effects, talk openly about them, and actively address them. Overall, it appears that monitoring not only the positives but also the risks of psychotherapy is key to its further development and to ensuring the greatest possible benefit for clients.

Recommended citation:

Rosendahl, J., Klatte, R., Frenzl, D., Castonguay, L. G., Vybíral, Z., & Strauss, B. (2025). Contextualizing the negative effects of psychotherapy. Nature Reviews Psychology, 1-17. http://dx.doi.org/10.1038/s44159-025-00472-8