Depression is diagnosed through a comprehensive assessment by a healthcare professional, such as a primary care physician, psychiatrist, psychiatric nurse practitioner or psychologist. The diagnostic process involves multiple steps to determine whether an individual meets the clinical criteria for depression and to rule out other conditions that may present with similar symptoms.
1. Clinical interview and symptom assessment
The first step in diagnosing depression is a detailed clinical interview. Your Empire State Psychiatry clinician will ask about the patient’s:
- Mood and emotional state
- Changes in sleep patterns, appetite, and energy levels
- Ability to concentrate and complete daily tasks
- Interest in activities once enjoyed
- Feelings of guilt, worthlessness, or hopelessness
- Thoughts of self-harm or suicide
This discussion helps determine whether the patient’s symptoms align with the evidence- based criteria for depression outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR).
2. DSM-5-TR Criteria for Major Depressive Disorder (MDD)
To be diagnosed with Major Depressive Disorder, a person must experience at least five of the following symptoms for at least two weeks, and at least one of the symptoms must be either a depressed mood or loss of interest or pleasure:
- Depressed mood most of the day, nearly every day
- Markedly diminished interest or pleasure in most activities
- Significant weight loss or gain, or changes in appetite
- Insomnia or excessive sleep (hypersomnia)
- Psychomotor agitation or retardation (restlessness or slowed movements)
- Fatigue or loss of energy
- Feelings of worthlessness or excessive guilt
- Difficulty concentrating or making decisions
- Recurrent thoughts of death, suicidal ideation, or suicide attempt
These symptoms must cause significant distress or impairment in daily functioning and must not be attributable to substance use or another medical condition.
3. Psychological Screening Tools
Clinicians often use standardized screening tools to help assess the severity of depression. Common assessments include:
- Patient Health Questionnaire-9 (PHQ-9) – A widely used tool that scores depressive symptoms.
- Beck Depression Inventory (BDI) – A self-reported questionnaire evaluating the intensity of depression.
- Hamilton Depression Rating Scale (HAM-D) – A clinician-administered questionnaire used in clinical settings.
While these tools do not confirm a diagnosis, they assist in identifying individuals who may need further evaluation.
4. Medical Evaluation and Laboratory Tests
Since some medical conditions can mimic depressive symptoms, a doctor may order laboratory tests to rule out:
- Thyroid disorders (hypothyroidism can cause fatigue and mood changes)
- Vitamin deficiencies (such as vitamin D or B12 deficiency)
- Chronic illnesses (such as diabetes or autoimmune disorders)
- Neurological conditions (such as Parkinson’s disease)
This helps ensure that the symptoms are due to depression rather than another medical issue.
5. Differential Diagnosis
Depression can sometimes be confused with or coexist with other mental health conditions, such as:
- Bipolar Disorder – Depressive episodes occur, but they are interspersed with manic or hypomanic episodes.
- Anxiety Disorders – Many individuals with depression also experience generalized anxiety disorder (GAD) or panic disorder.
- Grief and Bereavement – Sadness related to loss is natural, but when prolonged and impairing, it may indicate depression.
- Substance Use Disorders – Alcohol or drug use can contribute to or exacerbate depressive symptoms.
A thorough evaluation ensures the correct diagnosis and an appropriate treatment plan.
