In order to diagnose depression, your doctor will first take a thorough history of your symptoms. They will also perform a physical exam. In some cases, they may order blood work or lab imaging. However, none of these tests diagnose depression. Instead, they are used to rule out potential medical causes of your symptoms.1-3
The main tool used to diagnose major depressive disorder (MDD) is a reference book called the DSM-5. Your doctor will use the DSM-5 to make a diagnosis of depression if your symptoms and mental health screening tests suggest that depression may be the source of your symptoms.4
Most of the time this process can be done by your primary care doctor. In many cases, where the cause of your symptoms is not clear, your primary doctor may refer you to a psychiatrist. This is a doctor who specializes in mental health conditions.3,5
Screening tests
It can be hard to talk about depression. If you are having symptoms of depression, you may not want to talk with your doctor about them. Because of this, many doctors screen for depression symptoms during appointments for other health issues. These screening tests can alert your doctor to possible depression so they can diagnose and treat it as soon as possible.3,6
Examples of screening tests used for depression are the Patient Health Questionnaire-9 (PHQ-9). The PHQ-9 asks detailed questions about signs and symptoms.3,6,7
Other common screening tests for depression are the Hamilton Depression Rating Scale (HAM-D) and the Edinburgh Postnatal Depression Scale (used for people at risk for depression after giving birth, called postpartum depression). There are also screening tests for other mental health issues. For example, the Generalized Anxiety Disorder Questionnaire (GAD-7) screens for anxiety.7
While these screening tests do not diagnose depression, they can alert your doctor that something might be going on. From there, you and your doctor can talk more about your experiences. Your doctor may then do a mental status exam (MSE).8
Mental status exam
If you screen positive for depression on a questionnaire or tell your doctor you are having mental health symptoms, they will often do an MSE. This is like a physical exam for your moods, thoughts, and feelings.9
Common things your doctor will look at during an MSE are:9
- Speech volume, amount, and speed
- General mood and any changes to it
- Changes in appearance (like grooming or hygiene issues)
- Motor function
- Thought process and content
- Insight and intelligence
- Perception of the world around you
- Any thoughts of suicide or homicide
Many of these categories can be assessed during normal conversations. If your doctor notices anything unusual, they may dig deeper. Some of these factors may point to certain mental health diagnoses.1,8
For example, fast speech and thoughts that are hard to follow may be signs of a manic episode that can come with bipolar disorder. Slow movements, trouble with basic grooming, and low mood are all signs of depression.1,8
If your doctor has any concerns about your mental health during this process, they will turn to the DSM-5 to help with diagnosis.5,8
What is the DSM-5?
The DSM-5 is the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. This is a guidebook that helps with diagnosing mental health conditions. In fact, it is the gold standard for diagnosis. The book describes many conditions and their symptoms. Each condition has a set of specific criteria (symptoms) that a person must meet in order to be diagnosed.5,8
The DSM was written and is updated every few years by psychiatrists and other mental health experts. These experts come from backgrounds like pediatrics, nursing, social work, general medicine, and more.5
The DSM-5 can be helpful for separating different conditions that look like one another. For example, other mental health conditions that can look like MDD include:8
- Grief
- Burnout
- Adjustment disorder
- Attention deficit/hyperactivity disorder (ADHD)
- Bipolar disorder
- Schizophrenia
Following the specific criteria listed in the DSM-5 for each of these can help lead to the correct diagnosis.8
What are the DSM-5 criteria for MDD?
In order to be diagnosed with MDD, a person must experience at least 5 out of the following 9 symptoms:1,8
- Having a low mood for most of the day (feeling depressed, being excessively tearful, or being irritable)
- Losing the ability to feel pleasure in response to things that once brought you joy (also called anhedonia)
- Significant changes in weight (losing weight or gaining weight)
- Sleeping too much (hypersomnia) or having trouble sleeping (insomnia)
- Having slowed-down movements or sped-up movements
- Having very low energy or fatigue
- Feeling guilty or worthless
- Having trouble thinking or concentrating
- Having thoughts of death or dying (including suicidal thoughts or behaviors)
The 5 or more symptoms must be present for most of the day, nearly every day, for at least 2 weeks. At least 1 of the symptoms must be a depressed mood or lack of pleasure. Symptoms must also interfere with a person’s ability to complete daily tasks like going to work or school. They must not be caused by another medical condition, mental health issue, or drug side effect.1,8
These symptoms can be reported by the person having them. They can also be reported by a loved one. For example, you might not notice you are moving or talking slowly. But even if you do not notice and a loved one does, it counts as one of the symptoms.1,8
Depression specifiers
There are also specifiers in the DSM-5 to help your doctor make a more specific diagnosis. MDD specifiers include having MDD with:1,8
- Anxious distress – Having symptoms of anxiety, like restlessness, worry, or tension
- Mixed features – Showing signs of mania or hypomania, like having an elevated mood, talking nonstop, and not sleeping
- Melancholic features – Significant sadness, gloominess, and guilt
- Atypical features – Having increased appetite, weight gain, excessive sleeping, or a feeling of heaviness in the limbs
- Psychotic features – Showing signs of psychosis (losing touch with reality), like hallucinations or delusions
- Catatonia – Having catatonic features, which are movement or speech changes including echoing others, not speaking at all, freezing in abnormal positions, or having repetitive movements
- Peripartum onset – First having symptoms during pregnancy or right after giving birth
- Seasonal pattern – Having symptoms only during certain times of the year, like in the winter
Your doctor will work with you to determine the underlying cause of your symptoms. If they diagnose you with MDD, they will help guide you through the next steps of treatment.