By Christian Jarrett

The structured nature of Cognitive Behavioural Therapy/CBT and its clearly defined principles (based on the links between thoughts, feelings and behaviours) make it relatively easy to train practitioners, to ensure standardised delivery and to measure outcomes. Consequently, CBT has revolutionised mental health care, allowing psychologists to alchemize therapy from an art into a science. For many mental health conditions, there is now considerable evidence that CBT is as, or more, effective than drug treatments. Yet, just like any form of psychotherapy, CBT is not without the risk of unwanted adverse effects.

A recent paper in Cognitive Therapy and Research outlines the nature and prevalence of these unwanted effects, based on structured interviews with 100 CBT-trained psychotherapists. “This is what therapists should know about when informing their patients about the upcoming merits and risks of treatment,” write Marie-Luise Schermuly-Haupt and her colleagues.

The researchers asked each CBT-therapist (78 per cent were female, average age 32, with an average of 5 years experience) to recall their most recent client who had taken part in at least 10 sessions of CBT. The chosen clients (51 per cent were female, average age 38) mostly had diagnoses of depression, anxiety or personality disorder, in the mild to moderate range.

The interviewer – an experienced clinical psychologist trained in CBT – followed the Unwanted Events-Adverse Treatment Reactions checklist, asking each therapist whether their client had experienced any of 17 possible unwanted events during therapy, such as deterioration, new symptoms, distress, strains in family relations, or stigma.

The therapists, who work at outpatient clinics in Germany, reported an average of 3.7 unwanted events per client. Based on the therapists’ descriptions, the interviewer then rated the likelihood of each unwanted event being directly attributable to the therapeutic process – making them a true side-effect (only those rated as “definitely related to treatment” were categorised as such).

Following this process, the researchers estimated that 43 per cent of clients had experienced at least one unwanted side-effect from CBT, equating to an average of .57 per client (one client had four, the maximum allowed by the research methodology): most often distress, deterioration and strains in family relations. Over 40 per cent of side-effects were rated as severe or very severe, and over 25 per cent lasted weeks or months, though the majority were mild or moderate and transient. “Psychotherapy is not harmless,” the researchers said. There was no evidence that any of the side-effects were due to unethical practice.

Examples of severe side-effects included: “suicidality, breakups, negative feedback from family members, withdrawal from relatives, feelings of shame or guilt, or intensive crying and emotional disturbance during sessions.”

Such effects are not so surprising when you consider that CBT can involve exposure therapy (i.e. gradual exposure to situations that provoke anxiety); discussing and focusing on one’s problems; reflecting on the sources of one’s stress, such as difficult relationships; frustration at lack of progress; and feelings of growing dependency on a therapist’s support.

The longer that a client had been in therapy, the more likely they were to have experienced one or more side-effects. Also, and against expectations, clients with milder symptoms were more likely to experience side-effects, perhaps because more serious symptoms mask such effects.

Interestingly, before the structured interviews, the therapists were asked off the top of their heads whether they felt their client had had any unwanted effects – in this case 74 per cent said they had not. Often it was only when prompted to think through the different examples of potential side-effects that they became aware of their prevalence. This chimes with earlier research that’s documented the biases that can lead therapists to believe therapy has been successful when it hasn’t.

Schermuly-Haupt and her colleagues said a conundrum raised by their findings was whether unpleasant reactions that may be an unavoidable aspect of the therapeutic process should be considered side-effects. “We argue that they are side-effects although they may be unavoidable, justified, or even needed and intended,” they said. “If there were an equally effective treatment that did not promote anxiety in the patient, the present form of exposure treatment would become unethical as it is a burden to the patient.”

There are reasons to treat the new findings with caution: the results depended on the therapists’ recall (an in-the-moment or diary-based methodology could overcome this problem), and about half the clients were also on psychoactive medication, so it’s possible some adverse effects could be attributable to the drugs rather than the therapy (even though this was not the interviewer’s judgment, and remember the researchers used a conservative estimate of side-effects, only considering those that were “definitely” related to therapy by their estimation, and ignoring those that they considered “rather” or “most probably” related).

The researchers concluded that “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.”

—Unwanted Events and Side Effects in Cognitive Behavior Therapy

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest

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