Selective Serotonin Reuptake Inhibitors (SSRIs) are used widely in the treatment of major depressive disorders and anxiety disorders.
The first antipsychotic drug (chlorpromazine) was discovered in the early 1950s, which then led to the development of a range of drugs to treat depression and other mental illnesses. (Healy, 2003:43-48). Fluoxetine (Prozac) was the first major SSRI to be marketed, which paved the way for the next generation of SSRIs. It is still commonly used along with other SSRIs and other classes of antidepressants, including TCAs and MAOIs. (Lemke & Williams, 2008:568-600).
There has been many studies undertaken and literature written to understand the mechanisms of SSRIs, how they impact people with different mental illnesses and severities, how they compare to other classes of antidepressants, as well as their efficacy and risks, both during a course of the drug and after taking the drug.
One of the main benefits of SSRIs is that they are able to improve the mental state of patients treated for moderate to severe depression, as well as those with anxiety disorders, OCD and eating disorders, often in combination with depression. There is a variety of clinical and anecdotal evidence of improvements to patients suffering with depression and other mental illnesses. A study by (Gibbons et al. 2012) concluded that the treatment effects observed for the drugs tested compared to the placebo were significant, irrespective of baseline depression severity.
However, the percentage of patients that report significant improvements in mood varies greatly within different studies. There is also variation around the baseline of depression severity of the patient. Two meta-analyses published in (Kirsch et al. 2008) and (Fournier et al. 2010) found SSRIs had little impact compared to a placebo for those with mild and moderate depression, while the benefits for those with severe depression varied from “relatively small” to “substantial”. The researchers attributed this to a reduction in the placebo effect rather than an increase in the efficacy of the medication. However, other researchers have questioned the statistical basis of the study, suggesting that it under estimates the effects of antidepressants. (Horder et al, 2010:1277-88; Fountoulakis & Möller 2010:1-8)
There are also many risks and side effects associated with SSRIs both during the course of taking the drug and once the patient ceases to continue to take the drug. One of the main risks is that of suicide, which is more prevalent in those who are under 25 and have recently started taking an SSRI. Patients often monitored closely in the first few months to ensure they so not become suicidal, especially if they are under 25 and have a history of suicidal thoughts or self harm. Analysis by the FDA of clinical trials on children with depression were found to have increased risks of suicidal behaviour and ideation. (Hammad et al. 2006). This is generally seen within the first 2 months of treatment (Cox et al 2014).
SSRIs also have other risks associated with them, including headaches, nausea, worsening of depressive symptoms, anxiety, dizziness, fatigue, and sexual dysfunction. These symptoms are often mild and temporary for most patients, so do not offer a serious cause for concern, but can outweigh any benefits that may be seen if small, or can impact mood if they persist over a longer period of time.
SSRIs can also cause discontinuation syndrome. This is where an SSRI is stopped abruptly, causing withdrawal effects. (Gelenberg et al. 2010:20; 39; 59) It is often suggested to taper off SSRI use slowly or switch to fluoxetine and taper, as it has a longer half life than other SSRIs, so the reduction is less of a shock to the system. (Renoir 2013). This also helps to reduce symptoms of nausea, headaches, chills, dizziness and insomnia, as well as relapses.
In conclusion, there are lots of differing clinical results and opinions from theoretical literature and clinical studies that suggest different levels of efficacy for SSRIs with some resulting in little or no benefits, and other showing statistical benefits from the use of SSRIs.
Current data would suggest that SSRIs can be somewhat hit and miss for patients suffering with depression and other mental illnesses. There is some evidence to suggest it can benefit patients, particularly those with major depression, but it is not currently agreed upon that SSRIs are an effective treatment as a first line response for depression and other mental illnesses. Data also suggests that the baseline depression severity can impact the effects of the SSRIs, as well as age, meaning generalising clinical trials to the wider population is difficult.