Online screening for depression: Here's what one physician thinks about it

Inquisitive reader Amy asked me if I had any opinions about online screening for depression. The British Medical Journal recently published a debate on this issue.

What an excellent question, Amy! I read the opposing arguments, and these are my thoughts:

First, I see two different issues. The first is whether the 9-question Patient Health Questionnaire (PHQ-9) is an appropriate tool to use to screen for depression. The second is whether the public should trust Google to administer the PHQ-9.

Before I do delve into that, though, let’s take a step back and consider the purpose of screening tools. Screening tools help physicians figure out how much more we should learn about a person. For example, asking for a person’s biological sex is a screening tool. The moment I learn that the person before me is female, I will ask her questions about menstruation and pregnancy history. I’ll skip those questions if the person is male. Similarly, if a person tells me that he smokes cigarettes, then I will ask more questions about how much and how often he smokes, what he gets out of smoking cigarettes, and if he thinks smoking causes him any problems. This helps me assess potential risks to his psychological and physical health. It also helps me assess if he has any interest in changing his smoking behaviors. Screening tools help us sort and gather information to generate diagnoses and interventions.

The literature states that the PHQ-9 was developed both to diagnose and measure the severity major depression. The PHQ-9 was modeled after the criteria for major depression in DSM-IV. Thus, the problems with the PHQ-9 for diagnosis are the same as the problems with the DSM for diagnosis: Context is completely missing. The authors of DSM argue that the situation and underlying causes of major depression don’t matter; they state that the presence of certain symptoms determine whether the diagnosis applies.

Long-time readers know my refrain: Context does matter. Major depression is “comorbid” with many other psychiatric conditions, meaning that someone experiencing the symptoms of major depression often experience symptoms of other psychiatric conditions. For example, bipolar disorder, by definition, includes episodes of major depression. People with diagnoses of post-traumatic stress disorder (PTSD) and schizophrenia often experience major depression. Some people who take drugs, whether prescribed or obtained from illicit sources, experience symptoms of major depression. Sometimes the symptoms of major depression are actually due to a medical condition, such as certain cancers, infectious diseases, or thyroid conditions.

There are several papers that make the case that the PHQ-9 is a useful tool in the screening for and diagnosis of major depression. Given that major depression is comorbid with other conditions, a positive PHQ-9 result is useful to help get people into care. A professional can then help clarify symptoms, determine possible diagnoses, and suggest treatment and other interventions. Recall that the purpose of diagnosis is to guide treatment.

Here is where we get into the second issue as to whether the public should trust Google to administer the PHQ-9. Most task forces agree that there is no point in performing screening tests if you can’t do anything with the results. If you can’t refer someone with a positive PHQ-9 result to a professional who can clarify diagnosis and provide treatment, then why bother? You’re potentially causing more problems and distress for the person seeking help. Thus, the question is whether Google will direct people with positive PHQ-9 results to helpful resources.

There is a shortage of psychiatrists and other mental health professionals in the US. One wonders if an online depression screening tool will lead people to believe that they are “majorly” depressed, when they are not. They will then seek services that are hard to find. If these individuals are able to get into primary care services, those medical professionals may not be able to determine if someone has depression because of bipolar disorder, or depression due to the recent death of a loved one. Wrong diagnosis often results in wrong treatment or overtreatment. Recall that we should first do no harm.

However, it is clear that people seek information about depression and other psychological experiences on the internet. The questions on the PHQ-9 can educate the public about the differences between major depression and having a sucky day. The more information and education we can provide to the public, the more empowered the public can feel about not only what isn’t going well, but also what they can do to improve their health and wellness. I do not view my work as a psychiatrist as a guild secret. The more understanding and communication we have in our communities, the more we can address our psychological health on individual and societal levels.

The other reaction I had to that BMJ debate was related to a comment that Dr. Duckworth made under “attitudinal barriers.” He noted that a “key reason may be that people with mental health conditions perceive that they do not need treatment. Studies show that they report attitudinal barriers to seeking care much more often than structural or financial barriers.”

I don’t see how the PHQ-9 is related to “attitudinal barriers.” Screening tests don’t reduce stigma. Sure, people may avoid treatment for depression because they don’t know that they are depressed. However, I suspect that more people avoid treatment for depression because of the stigma associated with psychiatric conditions and treatment. If we want to reduce and remove “attitudinal barriers” related to depression, we must help share stories that remind everyone that people with depression are, first, people. The PHQ-9 is not a means to that end.

I don’t know the workings of Google well enough to comment more about whether we should trust Google to administer the PHQ-9. Others with more knowledge about online security, marketing, and data mining can say more about whether Google will use PHQ-9 results for good or evil … or both. There are likely other unintended consequences that I don’t know or understand.