We need to move beyond simple checklists for diagnosing and assessing depression.
Written by: John Kruse MD, PhD
This article is part of a Wise & Well Special Report: The United States of Depression.
Depression causes confusion and pain. It dulls the mind. It kills thousands of Americans each year through suicide. But it also bleeds into physical ailments, increasing the likelihood of serious accidents or of developing life-threatening conditions like heart disease or dementia. If you have a major illness like diabetes or cancer, depression elevates the likelihood that you’ll succumb to that condition. Depression blurs distinctions between mind and body.
One pervasive, if minor, way that “depression” causes confusion and pain is the contrast between the precise medical definition and the broader, everyday usage.
Maybe you really were depressed when your team lost the playoffs, you didn’t score those Taylor Swift tickets, or your local shop was out of your favorite double chocolate espresso banana chip mocha fudge swirl ice cream. But more likely you were just temporarily upset, disappointed, or irritated. Referring to those feelings as being “depressed” trivializes the pain and significance of clinical depression.
Some argue that even our medical definition of depression lacks real meaning. But even if imperfect, our current understanding has provided powerful help to millions of depressed individuals. “Depression” is more than a mere label. It helps people understand what they are suffering from and predict what is likely to happen without treatment, and it offers useful guidance for effective remedies.
How the experts think about depression
The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM) provides a worldwide standard for identifying depression. Fierce battles between adherents of different psychotherapy approaches marked the early years of the DSM. Conflict then followed between partisans of biological versus psychological origins of mental health conditions. To avoid this infighting, for the last half-century the DSM has tried to describe conditions simply in terms of observable or readily detectable indicators.
The DSM uses both symptoms ( characteristics of a condition apparent to a patient), along with signs (attributes discernible to an observer), to make a diagnosis. This approach, supposedly neutral regarding theories about the origins of mental illness, creates its own theoretical framework, which is currently fraying at the edges.
During a diagnostic interview for depression, the evaluator elicits an individual’s history, family history, and current medication and medical information. Physical signs and symptoms can indicate medical conditions like thyroid imbalances or vitamin deficiencies that might cause depression. Blood tests or other studies might be ordered to rule out such conditions.
Beyond just focusing on the answers to questions, the evaluator must pay attention to how they are answered. Is speech slow and ponderous? Are there long pauses or awkward silences? Are certain topics avoided? Any sighing, grimacing, or crying? The modern tendency to focus on filling in boxes on computer screens risks missing all of this vital information.
Even more importantly, focusing on a screen or checklist can interfere with forming a human alliance. It ignores that two individuals (doctor and patient) have come together to try to solve or resolve the depression. The strength of the patient-therapist alliance is one of the best predictors of a good outcome.
To fulfill a diagnosis of depression in the most current version of the DSM requires that one displays at least five of the nine following symptoms. These symptoms need to be a departure from the individual’s baseline. They need to be pervasively present for nearly every day during at least a two-week period. They need to cause significant distress or impairment in one’s social or occupational role. Those five symptoms must include at least the first or second criteria from the list below:
- feeling sad, down, hopeless, or empty (or sometimes irritable or numb)
- loss of interest or pleasure in activities
- weight loss, or gain, of at least 5% of body weight, or significant appetite loss or gain
- insomnia or hypersomnia (excessive sleeping)
- agitated bodily movements, or slowed down and sluggish movements
- fatigue without exertion
- feeling worthless, or inappropriate guilt
- decreased concentration or indecisiveness
- thoughts of death/suicide, but not just worries about dying
In addition to fulfilling at least five symptoms, additional rule-out criteria include that these symptoms are:
- not due to substance abuse or medical condition
- not explained by a psychotic or delusional disorder
- not in the context of a history of mania or hypomania
This may sound like an atrocious mess. In all, 227 different collections of symptoms could lead to a depression diagnosis. Two people could have depression with absolutely no symptoms in common. But in samples of real individuals, many of the symptoms tend to cluster together. Fully 10% of depressed individuals have all nine of the symptoms. Almost half of depressed people fall into just nine out of the 227 possible combinations of symptoms.
The last of the rule-out criteria distinguishes people who have only depressive episodes (what we call unipolar depression) from those who also have manic episodes (bipolar disorder, formerly called manic depression). Although unipolar and bipolar depressions may appear indistinguishable, medications can have different impact on these two different conditions.
Attempts to parse depression into smaller pieces haven’t proven too useful. For example, “situational” and “innate, or genetic” depressions tend to respond to the same medications and therapies. Perhaps future insights from neuroscience will lead to more clarity regarding subtypes of depression.
Regarding who is likely to become depressed, the same three factors keep emerging from large, population-based studies. Most people who become depressed have:
- a significant family history of depression
- major loss or trauma in the first decade of life
- loss or trauma in the six months preceding their current episode
Different psychiatrists are likely to come to the same diagnosis of depression when using the DSM criteria to evaluate an individual. Researchers call this good validity. But identifying depression doesn’t go very far toward telling us what depression is.
The many many (partial) causes of depression
Humans simultaneously exist and function at a multitude of levels; we’re all playing three-dimensional chess. The three levels most immediately relevant to understanding depression are biological, psychological, and social. Maybe drilling down to the quantum mechanical level will reveal significant implications for the unpredictability of matter and mood. Some would consider the spiritual level important enough to stand alone, rather than lumping it as a subset of the social. But currently we understand depression as resulting from biological, psychological, and social forces.
Depression is (partially) a genetic condition. Family lineages and gene sequencing both confirm that a huge number of genes each confer a tiny increased risk to developing depression. There is no single depression gene. Many of the gene variants contributing to depression also increase the risk of developing other mental health conditions.
Depression is (partially) a neurochemical condition. Depression is not a simple serotonin deficit; if it were, then many of our antidepressants would work within hours. Drugs that modulate receptor systems for serotonin, dopamine, norepinephrine, glutamate, opioids, or steroids can all alleviate depression, at least some of the time.
Depression is (partially) a hormonal condition. Throughout their reproductive years, women are twice as likely to become depressed as men.
Depression is (partially) a neuroanatomical condition. The hippocampus of depressed individuals are smaller than those never depressed. The longer the time in depression, the smaller the hippocampus. Depressed people have an overly strongly connected default mode network, which is the set of pathways involved in ruminative self-assessment.
Depression is (partially) a neuro-electrical condition. Triggering brain cells with electricity to the whole brain, with electrodes to certain brain regions, with shocks to the vague nerve, with current to the scalp, or with magnetically induced electrical changes can alleviate depression.
Depression is (partially) a psychological condition. Psychotherapies ranging from cognitive behavioral therapy, to mindfulness-based approaches, to interpersonal therapies, to psychoanalytic can all alleviate depression.
Our DSM criteria, largely to avoid favoring any particular school of psychotherapy, downplay the psychologic components of depression. The DSM doesn’t even list “social withdrawal” which many consider the “most common telltale sign of depression.”
The DSM also fails to capture how burdensome depression feels. Depressed people don’t just feel tired, or fatigued, or have low energy. Simple tasks, like getting out of bed, or choosing which pants to wear, feel like an incredible burden. Depressed people worry that their mere presence creates a huge burden on family and friends. Depressed people feel that their existence is burden on the whole society.
Depression is (partially) a social condition. Increases in poverty lead to higher rates of depression. Increased levels of violence, whether through war, street crime, or domestic abuse, lead to higher rates of depression. Isolation, disconnection, and loneliness lead to greater rates of depression. Discrimination, stigmatization, and inequity lead to depression.
We’re multidimensional creatures, and depression manifests at many of the levels we live at. Depression is more than just a collection of symptoms. When I work with someone who is depressed, my job is always to push back against depression at as many levels as possible — which may include medications, or exercise, or diet, or sleep scheduling, or psychotherapy, or changing jobs/relationships/society. All of these are points of leverage in the battle to return to a depression-free state.
An evolutionary psychiatry perspective helps make sense of many of these levels of involvement. For millions of years we have been social animals, dependent for survival on fitting in with our clan. Settling conflicts with battles to the death didn’t enhance survival. We developed ways for less powerful individuals to submit to those more powerful — the behavioral equivalent to a dog or wolf rolling over and showing its belly. The behaviors, assessments of self and others, and biochemical responses that were adaptive in those ancient conflict situations became part of our heritage. This collection of reactions comprises what we identify today as depression.
In modern humans, a loss of connection or a loss of status can elicit these old adaptive responses. This happens regardless of whether these responses are an effective way to deal with the current situation. These ingrained responses also have a tendency to persist for long after they may be useful, particularly when part of the brain is ready to yield and move on, and other parts want to continue battling.
The evolutionary understanding of depression can help patients let go of shame. Depressed people are quite proficient at feeling shame, often beating themselves up just for being depressed. It reduces shame to realize that one’s responses are inherent in all humans, and are adaptive mechanisms that have been inappropriately triggered or perpetuated. Furthermore, an evolutionary awareness helps redirect attention towards what could be a more functional response. This might be grieving and then accepting the loss, or it may be uncovering ways to continue to fight, if there are good reasons for doing so.
Checklists fall short in assessing depression severity
Most of our ways of measuring depression align closely with how we diagnose it, and consist of symptom checklists. For years these checklists were relegated to mental health researchers. They used these rating tools to determine what therapies (medications, talking therapies, or other interventions) were effective in treating depression.
Now symptom checklists pervade the clinic and therapy office. General practitioners are goaded to administer and chart the results of brief depression surveys. Patients are asked to fill out questionnaires online or in the waiting room. By measuring depression in this manner, the doctor or therapist can theoretically adapt treatment strategies that are ineffective or only partially effective and can target residual symptoms for attention.
The computer era has solidified the desire to quantify everything. The underlying assumption is that if we can measure something then we can also control it. This thinking is not unique to mental health treatment. We reduce hypertension to a blood pressure reading, or obesity to a BMI measurement, thinking we have captured everything that is important about the condition. Even if we ignore all of the other factors (circadian rhythms, activity levels, emotional states, metabolic rates, genetic heritage) that should affect how we interpret any individual number.
Mental health, including depression treatment, is on more treacherous ground. A depression score is just a tally of how many symptoms one currently has. This omits a vast amount of relevant social, psychological, and biological data relevant to one’s depression status.
One recent study tried to improve upon simple depression symptom lists as a way of measuring depression severity. The researchers elicited additional patient ratings about how well they were functioning in their life, and how they viewed the quality of their life. This almost doubled the number of questions asked. But scoring these additional questions revealed that significant numbers of people who were considered to be non-responders to their antidepressant medication, based on their symptom scores, were actually feeling considerably better after their treatment. These additional questions captured important information that the symptom checklists had missed.
For years I’ve thought that if we had better measures for depression, we could demonstrate more clearly that antidepressants work for many depressed people.
The problem isn’t that our medications are only slightly better than placebos, the problem is that we don’t measure depression very well. Perhaps adding questions that capture life functioning, or emotional status, like in the study above, would reveal that treatment with antidepressants robustly improved the functioning and well-being of individuals that had been depressed.
On the other hand, adding more and more variables has no clear endpoint. Fundamentally, this is a left-brain, reductionistic approach. We are trying to assemble a set of criteria, assess whether a person meets each of them or not, and then come up with an algorithm or set of rules to determine how depressed they are. The problem is that we will always be leaving out some details, and we are likely missing the bigger picture by focusing on the details.
A right-brain approach addresses the issue more holistically, and simply. We could just ask, “On a scale of 1 to 10, how bad is your depression today?” I’m convinced that this would yield a clearer measure of depression. It would be pretty easy to administer. We would be far closer to capturing the essence of an individual’s depression and whether or not they are improving.
The right brain approach doesn’t involve throwing out all of the symptom checklists of the left brain. It compliments them, and incorporates the information they collected. Even though depression can impair memory, concentration, and processing speed, most depressed brains can still tell us how depressed they are.
Michael J McCluskey 