Unwanted Events and Side Effects in CBT: the Study

Unwanted Events and Side Effects in Cognitive Behavior Therapy – Cognitive Therapy and Research – June 2018


Side effects (SEs)are negative reactions to an appropriately delivered treatment, which must be discriminated from unwanted events (UEs) or consequences of inadequate treatment.

One hundred CBT therapists were interviewed for UEs and SEs in one of their current outpatients.

Therapists reported 372 UEs in 98 patients and SEs in 43 patients. 

Most frequent were

  • “negative wellbeing/distress” (27% of patients),
  • “worsening of symptoms” (9%),
  • “strains in family relations” (6%);
  • 21% of patients suffered from severe or very severe and
  • 5% from persistent SEs.

SEs are unavoidable and frequent also in well-delivered CBT. They include both symptoms and the impairment of social life. Knowledge about the side effect profile can improve early recognition of SEs, safeguard patients, and enhance therapy outcome.


To our knowledge, this is the first study to attempt to separate unwanted events (UE), adverse treatment reactions (ATR), and side effects (SE) in a large sample of psychotherapy patients.

It demonstrates that one can make this distinction, and it confirms the concept and the tool. Looking for unwanted events independent of any early judgment as to causality helps to overcome the non-recognition bias of therapists.

We found that 74% of therapists were not aware of any side effects in their treatment before the systematic evaluation began. The present findings suggest that the use of structured assessment methods like the UE-ATR Checklist can improve the recognition of side effects

A separate judgment about whether an unwanted event is an adverse treatment reaction helps to avoid incorrectly inflating the rate of side effects. In our sample, 98% of patients had experienced some unwanted events, but only 43% were found to suffer from adverse treatment reactions or side effects.

It is an open question who is in the best position to report side effects:

  • the patient,
  • the therapist or
  • other professionals.

The patient is positioned to identify negative feelings or outcomes, but does not have the professional knowledge or perspective to say whether these are side effects.

The therapist can make a judgment about side effects, especially those of clinical relevance, but may have a recognition or judgement bias.

Our method of having an independent professional interview the therapist is perhaps best, though it might be improved if a separate interview of the patient had been possible. Future research should combine both perspectives.

We found 372 unwanted events in 98 of 100 patients. Unwanted events that were “definitely related” to treatment were found in 43% of cases.

This is a conservative estimate of side effects. Had we included those unwanted events that were rated as “most probably” and “rather related” to the treatment, 63% of cases would have been classified as suffering from side effects.

A point of discussion is whether ordinary reactions to CBT which may be indispensable for the success of treatment, such as distress during exposure treatment should be called “side effects”. We argue that they are side effects although they may be unavoidable, justified, or even needed and intended

It is important to make a distinction between

  1. unavoidable and possibly even intended negative effects on one side, and
  2. desired ones on the other.

This is a general rule in medicine, like in surgery, where in earlier times it may have been necessary, unavoidable and intended to remove a breast to fight cancer. But still, it was not desired and so surgeons developed new treatments without this burden to the patient.

Unavoidable and intended negative effects are burdens to the patient and therefore undesired.

This is especially true considering that “unavoidable” is often a judgment call made by the treating doctor, whose interests would not necessarily reflect those of the patient.

To acknowledge this is important for the improvement of psychotherapy in the individual case as this can help to avoid unnecessary distress for the patient and select the best treatment option. It is also important for the development of treatment alternatives that are better tolerated, similar to the development of strategies in surgery which allow to keep a breast.

Most of the side effects in this study were rated as mild or moderate (59.6%) and transient (89.6%). However, more than 40% of side effects were rated as severe (i.e., countermeasures are necessary) or very severe (i.e. enduring negative consequences) and 8.8% as persistent. Psychotherapy is not harmless.

Apart from prevalence, our data also show that side effects are very multi-facetted in regard to type and content.

  • Deterioration of symptoms can be caused by increased feelings of hopelessness or despair when looking at existing problems.
  • Feelings of dependency and lack of self-efficacy can be caused by a very close and supportive therapeutic relation.
  • Break up of relations with partners or parents, or avoidance of work can result from explicit or implicit incrimination of living situations.
  • Problems in therapy cooperation can follow feelings of shame after not doing homework assignments.

Still, these examples show that regular and appropriate therapeutic interventions can have negative consequences, which may even be enduring like

  • quitting a job,  [and this is ethical?]
  • getting into trouble with close persons,
  • undermining of self-confidence, or
  • aggravation of problem perception.

The positive correlation between number of sessions and number of unwanted events and side effects gives validity to the assessment, as more unwanted events should emerge over the course of time.

An interesting and somewhat unexpected finding was that patients with side effects had lower scores on the FSCL, which suggests that side effects are not an expression of severity of illness. It can be assumed that mild side effects are better recognized in less severe cases. The FSCL score was the only significant predictor of side effects.

An awareness and recognition of unwanted events and side effects in all therapies will benefit patients, improve therapy or reduce attrition, analogous to the benefit of measurement-based monitoring of treatment progress

The therapist bias of not seeing side effects must be overcome during training.

The research question is not only to describe side effects but also to develop strategies on what to do should they occur, to identify patients at risk, and to develop therapies without certain side effects

Finally, the data describe the SE profile of CBT under routine clinical conditions in a heterogenous patient population. This is what can occur with some probability in patients undergoing this mode of treatment. Therapist can use this knowledge when informing their patients about the treatment and also for risk monitoring in the course of treatment.

Negative Effects of Psychological Treatments: An Exploratory Factor Analysis of the Negative Effects Questionnaire for Monitoring and Reporting Adverse and Unwanted Events – June 22, 2016

Research conducted during the last decades has provided increasing evidence for the use of psychological treatments for a number of psychiatric disorders and somatic complaints.

Somatic = physical.

However, by focusing only on the positive outcomes, less attention has been given to the potential of negative effects.

Despite indications of deterioration and other adverse and unwanted events during treatment, little is known about their occurrence and characteristics.

Hence, in order to facilitate research of negative effects, a new instrument for monitoring and reporting their incidence and impact was developed using a consensus among researchers, self-reports by patients, and a literature review: the Negative Effects Questionnaire

The derived factors were:

  • symptoms,
  • quality,
  • dependency,
  • stigma,
  • hopelessness, and
  • failure.

Items related to unpleasant memories, stress, and anxiety were experienced by more than one-third of the participants.

Further, increased or novel symptoms, as well as lack of quality in the treatment and therapeutic relationship rendered the highest self-reported negative impact.

In addition, the findings were discussed in relation to prior research and other similar instruments of adverse and unwanted events, giving credence to the items that are included.

The instrument is presently available in eleven different languages and can be freely downloaded and used from www.neqscale.com.

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