Comparing the effectiveness of pharmacological and psychological treatments for depression

Nathnael Bekele

Depression is a mental illness that affects how one feels and acts (APA). The significant symptoms of depression include feeling sad, loss of interest in activities once enjoyed, changes in appetite, trouble sleeping or sleeping too much, loss of energy, feeling worthless, and more (APA). It has several risk factors including biochemistry, genetics, personality, and environmental factors (APA). Fortunately, 80% - 90% of people with depression eventually respond well to treatment (APA. This is good news considering 6% of US adults had at least one major depressive episode with severe impairment in 2020 (NIMH). The most common forms of treatment for depression are medication and psychotherapy.

Pharmacological treatment of depression is used to maintain the chemical balance of hormones, especially serotonin, in the brain. The general term for these medications is “antidepressants”. The most common antidepressants used are tricyclic antidepressants (TCAs), selective serotonin re-uptake inhibitors (SSRIs), and selective serotonin noradrenaline re-uptake inhibitors (SNRIs) (IQWiG).

“Even though not all details are known, experts believe that depression is caused by an imbalance of certain chemical messengers (neurotransmitters) like serotonin, which means that signals can't be passed along the nerves properly. Antidepressants aim to increase the availability of these chemicals.” (IQWiG)

A common form of psychotherapy used for depression is Cognitive Behavioral Therapy also referred to as CBT. It is used for the treatment of a range of mental illnesses including depression, anxiety disorders, alcohol and drug use problems, and even severe illnesses (APA). CBT involves a psychologist helping a patient better understand their behavior, find healthy ways to cope with difficult situations, and improve their confidence (APA). These forms of treatment work because it is thought that “psychological problems are based, in part, on faulty ways of thinking, learned patterns of unhelpful behavior, and because people suffering from psychological problems can learn better ways of coping with them, thereby relieving their symptoms” (APA).

It is not necessary for CBT sessions to be in person. Linde et al have found that the effects of less resource-intensive treatments including online meetings have similar effects to more intense methods such as in-person sessions. Hence, with the increased popularity and availability of online communication due to COVID-19 lockdowns, it might be easier to get help for depression.

Patients sometimes opt out of taking antidepressants when getting treated for depression. But are there significant differences in the effectiveness of antidepressants compared to CBT?

One study found that drugs including TCA and SSRI “were significantly better than placebo, with an average reduction in symptom severity of 48.0% versus 31.3%” for treatment of depression in patients over the age of 55 (Gerson). Furthermore, “no single drug or group of drugs was superior in terms of efficacy” (Gerson). Compared to CBT, antidepressants have a similar effect in relieving symptoms of depression (Gerson). Gerson points out that there is limited data available for CBT effectiveness for people over the age of 55. Hence, the recommendations of trained professionals should come first in making decisions.

An observational study by Linde et al comparing the remission of symptoms among patients with depression receiving a placebo treatment, psychological treatment, pharmacotherapy, and a combination treatment found that “the results on face-to-face interpersonal psychotherapy are somewhat discouraging showing little to no benefit over usual care unless it is combined with pharmacotherapy”. This study also found that in-person CBT sessions had similar effectiveness to less resource-intensive interactions such as online sessions.

However, a study by Gartlehner et al found that “in contrast to pharmacological treatments, the majority of non-pharmacological interventions for treating patients with MDD [major depressive disorder] are not evidence-based.” Only CBT is as effective as antidepressants. This highlights the different opinions present amongst psychologists. Some opt to treat patients using CBT while some opt to use other methods such as psychoanalysis or humanistic therapy.

These three studies together suggest that CBT is the most preferable form of psychological treatment compared to other psychotherapeutic options. Also, antidepressants seem to be as effective or more effective than CBT in relieving symptoms. However, even though we know antidepressants are good at treating depression, we still don’t know how they actually work (Jeyasingam). A combination of psychological and pharmacological intervention also seems to be an option as opposed to choosing just one. Hence, it is important to discuss with a psychiatrist which option is best for a patient because of differences in effectiveness due to age, gender, and other variables. Also, the causes of depression can dictate which treatment option is best.

An interesting question is whether psychological and pharmacological treatments result in the same changes in brain chemistry and if the different processes manifest themselves the same way in treating depression. This would give insight into not just biological questions but philosophical ones such as those raised by Descartes: is there a separation between consciousness and the corporeal body?

Sources

Gartlehner G, Wagner G, Matyas N, et alPharmacological and non-pharmacological treatments for major depressive disorder: review of systematic reviewsBMJ Open 2017;7:e014912. doi: 10.1136/bmjopen-2016-014912

Gerson, S et al. “Pharmacological and psychological treatments for depressed older patients: a meta-analysis and overview of recent findings.” Harvard review of psychiatry vol. 7,1 (1999): 1-28.

InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Depression: How effective are antidepressants? [Updated 2020 Jun 18]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK361016/

Jeyasingam, Neil R. “How Do Antidepressants Work? - Neil R. Jeyasingam.” YouTube, YouTube, 18 Mar. 2021, www.youtube.com/watch?v=ClPVJ25Ka4k.

Linde, Klaus et al. “Effectiveness of psychological treatments for depressive disorders in primary care: systematic review and meta-analysis.” Annals of family medicine vol. 13,1 (2015): 56-68. doi:10.1370/afm.1719

“Major Depression.” National Institute of Mental Health, U.S. Department of Health and Human Services, www.nimh.nih.gov/health/statistics/major-depression.

“What Is Depression?” Psychiatry.org - What Is Depression?, psychiatry.org/patients-families/depression/what-is-depression#section_1