Weighing firsthand reports of experiences with finasteride

This page explores whether firsthand reports of experiences taking finasteride, many of which are found on social media sites, have any truth to them. I make the argument that they do, if 1) they are broadly consistent across different sources; and 2) they are consistent with other types of evidence such as published research, adverse event reports, case reports and clinical experience. In other words, firsthand reports can have value as converging evidence.

Reading critically with an open mind

Of course, posts and comments found on social media sites should not be assumed to be complete, definitive or conclusive evidence of anything. We should bring a critical eye to them, as with any type of evidence. These reports are not sufficient, on their own, to establish a safety profile for a drug. They are not systematically collected or verified. They are voluntary, open-ended, informal and often anonymous. They are subject to the individual’s perspective. Nevertheless, these reports are a form of evidence, and can be of value in light of the principle of converging evidence.

Converging evidence

Converging evidence refers to themes that arise across multiple forms of evidence. If we see the same themes coming up across online reports by former users of finasteride, adverse event reports to FDA, physician case reports, physician experience and published research, this makes a stronger case than a theme that only appears in one or two forms of evidence.

Every form of evidence has advantages and limitations—including what is called the “gold standard” of evidence-based medicine, the randomized controlled trial (RCT). For example, participants in an RCT may be unwilling to share personal, socially unacceptable adverse effects with investigators unknown to them. The formal, structured setting of the trial may introduce expectations and placebo effects not present in other settings. A drug may be taken more consistently (without interruptions) in a trial than in everyday life, and this may have implications for adverse effects in each setting. The trial may not have follow-up over the very long term (say, five or ten years)—or even if it does, crucial information may be lost when participants drop out.

The value of firsthand reports

Having noted the limitations of first-person reports, these reports also have strengths: they capture a person’s unfiltered opinion. They may include rich details and context not found in clinical trials, case reports, epidemiological studies or pharmacovigilance statistics.

In discussion threads, we can see numerous perspectives and dialogues play out. Others may ask for more information or express skepticism, prompting the original poster to reply with additional points or background.

The reports may be written as events are happening, or they may summarize years of experience. This is a flexible format that, while not definitive (no form of evidence is) has value as a source of converging evidence.

Cultural context

Just like social groups offline, online groups have a culture that shapes conversations within it. Each online community’s culture differs depending on its platform, history and moderation. In general, hair loss forums are less hospitable to accounts of adverse effects and in some cases will mock or attack people who report them. Communities intended to provide support for post-finasteride syndrome will focus on symptoms and attempts at treatment, and discourage discussions about taking or starting finasteride.

Sources of firsthand reports

See this post: Where are firsthand reports of finasteride’s adverse effects and post-finasteride syndrome?