How to screen for, diagnose and treat major depressive disorder as a primary care physician

Depression is a leading cause of disability and costs the global economy roughly $1 trillion annually in lost productivity alone. Many patients with major depressive disorder (MDD) present first to their primary care physicians (PCPs), who will ideally perform a thorough screening and provide a diagnosis and treatment plan.

Since 2016, the U.S. Preventive Services Task Force guidelines have strongly recommended that MDD screenings should be implemented on any adults who see a primary care clinician. As a result, PCPs have taken on a bigger role in the treatment of MDD.

In order to successfully screen for MDD as a primary care physician, one needs to understand the DSM-5 criteria that establishes the diagnosis of MDD. Patients with MDD are those that exhibit five or more DSM-5 (see bottom of article) criteria during a two-week period with clinically significant distress or impairment in social, occupational, or other important areas of functioning.

Notably, such symptoms must not be due to the direct physiological effects of a substance (e.g., drug abuse, a prescribed medication’s side effects) or a medical condition. Also, the patient must have never met criteria for mania or hypomania, and physicians should rule out schizophrenia or psychotic disorder as well, as many psychotic processes can have negative symptoms that appear first.

One of the DSM-5 criteria, based off of the Diagnostic and Statistical Manual of Mental Disorders, must be depressed mood or anhedonia. The severity of the depression can be further evaluated with a clinical assessment and valid screening tool, such as the Patient Health Questionnaire for Depression (PHQ-9). A PHQ-9 score with 9 points or higher equals a sensitivity of 74% and a specificity of 91% in primary care settings.

How clinicians diagnose major depressive disorder

“A patients’ clinical presentation, along with the PHQ-9 and labs, are used to make a definitive diagnosis of MDD,” said Kinsley Jin, MD, a family medicine physician in Aurora, Illinois. “Patients will often present differently depending on their age range, comorbid diseases and level of pain. In the younger patients I tend to see more of a lack of motivation, concentration, decreased work productivity and substance use, whereas in the older patients they complain of fatigue and sleep disturbances.

“Comorbid conditions very often overlap with depression. Examples of such disease states in older patients are chronic pain syndrome, delirium, UTI and various forms of dementia. I check labs to rule out other medical reasons for the depression.”

Once the clinical assessment, labs and PHQ-9 are evaluated, the clinician is ready to diagnose the patient with MDD and its severity in order to formulate a satisfactory treatment plan. A PHQ-9 of 5 or greater indicates mild depression, whereas 9 or higher is considered moderate depression.

“At a PHQ-9 level of 5, I am confident that I can treat the patient and monitor them closely,” said Gemma De La Cruz, FNP, a family nurse practitioner in Woodstock, Illinois. “Depending on their clinical situation and how they answer the PHQ-9, I will choose cognitive behavioral therapy (CBT) solely, or an SSRI and cognitive behavioral therapy concurrently. If the patient has no history of mental illness and describes suicidal ideation, that is the time that I complete the Columbia Suicide Severity Rating Scale (C-SSRS) to determine if the patient should be referred to a psychiatrist or hospitalized.

“For the mild MDD patient, I follow up with them in a week to go over labs and make sure they are not experiencing side effects to the medications. If they are doing okay, then I wait another four weeks and reassess thereafter, also using the PHQ-9 as an objective measure.”

Each time the patient is evaluated for MDD they should be asked directly about their suicidal thoughts, intent or plans.

Between 1999 and 2018, the age-adjusted suicide rate in the United States increased by 35%, most notably between 2006 and 2018. The best predictor of dying by suicide is a prior suicide attempt. The C-SSRS is helpful in providing insight as to the severity of the MDD with very detailed questions regarding suicidal behavior.

When to consult a psychiatrist for major depressive disorder

Due to their specialized training, psychiatrists are best equipped to handle patients who are at significant risk of suicide. Primary care physicians should consider consulting psychiatry in the following cases:

1. If the patient is refractory to initial treatment attempts or the diagnosis of MDD remains uncertain. 
2. There are severe comorbid psychiatric conditions that exist in addition to the MDD such as bipolar disorder, GAD, schizophrenia or complex personality disorders, or if the patient has MDD with psychotic features. 
3. The patient has been diagnosed with a substance use disorder that is untreated. 
4. The patient is a high suicide risk by clinical judgment and/or high PHQ numbers; greater than 15 is moderate to severe MDD. 

Who patients are turning to in time of need

PCPs typically know their patients better than specialists, and most patients trust their PCPs more than other healthcare professionals due to a higher frequency of involvement with them. Many PCPs can effectively treat MDD through close follow-up—if possible, with the help of an integrative care team consisting of a clinical therapist or a nurse.

The role of the team would be to assist the PCP in monitoring medication adherence, reinforcing education of medication use and side effects, and assessing for self-harm, danger to others or emergence of other psychiatric disorders. Employing these strategies in the treatment of MDD has helped many patients improve and achieve remission of symptoms.

Medications should be continued in younger adults for at least six to 12 months to prevent a relapse of MDD when medication is stopped. Monitoring of MDD is done through the PHQ-9 and clinical assessment of complete return to normal functioning.

In older patients (age 65+) with remission of symptoms, the medications should be continued for two years thereafter. For patients with two or more prior episodes, residual symptoms, greater severity of symptoms or other high-risk features, consult clinical guidelines for the recommended duration of treatment, which may be indefinitely.

Honesty between patient and physician

The successful treatment of MDD not only involves medication and CBT, but also requires the patient to focus on self-care and be actively engaged in their own self-discovery of traumas and triggering events.

The key to combatting MDD is building personal resilience through a partnership with the PCP directing treatment for the patient in regard to goal-setting, accountability, self-regulation of emotions and, if necessary, overcoming social isolation.

“You need to provide a sense of hope for the patients and go over achievable short-term goals to combat the depression,” said Dr. Jin. “They have to be willing to change the way they think about their lives and find in you a person whose opinion they can trust.”

MDD can be challenging to treat, but PCPs are well-positioned to help patients begin their journey toward mental well-being. The initial bonds of trust and open communication between the PCP and the patient are necessary to begin successful treatment of MDD.

Thereafter, close follow-up is essential to achieve patient-centered goals, assess medication adherence, track progress and provide a continued sense of hope for the patient. Please be aware that patients often need to try different medications and second-step strategies such as counseling or psychotherapy to successfully recover from MDD.

The ultimate objective for the PCP is to get the patient back to their normal level of functioning and help them feel like themselves again.

If you are or someone you know is experiencing a mental health crisis, there are resources available now:

• You can seek immediate help in an emergency room or dial the Suicide and Crisis Lifeline at 988
• The national crisis text line can be reached by texting HOME to 741741
• The Physician Support Line, a free, confidential support service run by volunteer psychiatrists, is available Monday through Friday, 8 a.m. to 11 p.m. ET, at (888) 409-0141

DSM-5 diagnostic criteria for MDD

A. Five (or more) of the following symptoms have been present during the same two-week period and represent a change from previous functioning; at least one of the symptoms is either (1) depressed mood or (2) loss of interest or pleasure.

NOTE: Do not include symptoms that are clearly attributable to another medical condition.

1. Depressed mood most of the day, nearly every day, as indicated by either subjective report (eg, feels sad, empty, hopeless) or observations made by others (eg, appears tearful). (NOTE: In children and adolescents, can be irritable mood.)
2. Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day (as indicated by either subjective account or observation).
3. Significant weight loss when not dieting or weight gain (eg, a change of more than 5% of body weight in a month), or decrease or increase in appetite nearly every day. (NOTE: In children, consider failure to make expected weight gain.)
4. Insomnia or hypersomnia nearly every day.
5. Psychomotor agitation or retardation nearly every day (observable by others, not merely subjective feelings of restlessness or being slowed down).
6. Fatigue or loss of energy nearly every day.
7. Feelings of worthlessness or excessive or inappropriate guilt (which may be delusional) nearly every day (not merely self-reproach or guilt about being sick).
8. Diminished ability to think or concentrate, or indecisiveness, nearly every day (either by their subjective account or as observed by others).
9. Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide.

B. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

C. The episode is not attributable to the direct physiological effects of a substance or to another medical condition.

NOTE: Criteria A through C represent a major depressive episode.

NOTE: Responses to a significant loss (eg, bereavement, financial ruin, losses from a natural disaster, a serious medical illness or disability) may include the feelings of intense sadness, rumination about the loss, insomnia, poor appetite, and weight loss noted in Criterion A, which may resemble a depressive episode. Although such symptoms may be understandable or considered appropriate to the loss, the presence of a major depressive episode in addition to the normal response to a significant loss should also be carefully considered. This decision inevitably requires the exercise of clinical judgement based on the individual’s history and the cultural norms for the expression of distress in the context of loss.

D. The occurrence of the major depressive episode is not better explained by schizoaffective disorder, schizophrenia, schizophreniform disorder, delusional disorder, or other specified and unspecified schizophrenia spectrum and other psychotic disorders.

E. There has never been a manic or hypomanic episode. NOTE: This exclusion does not apply if all of the manic-like or hypomanic-like episodes are substance-induced or are attributable to the physiological effects of another medical condition.

Related reading in The DO:

15 minutes under paper weight: Why medicine’s most meaningful moments can’t be charted

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Related reading in the Journal of Osteopathic Medicine:

Firearm safety and suicide prevention in older adults: a primary care clinical framework