What are the diagnostic criteria and initial treatment approach for a patient presenting with symptoms of depression according to the DSM-5 TR (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision)?

DSM-5 TR Diagnostic Criteria for Major Depressive Disorder

Major Depressive Disorder requires at least 5 out of 9 symptoms present during the same 2-week period, with at least one symptom being either depressed mood or loss of interest/pleasure (anhedonia), causing clinically significant distress or functional impairment. 1, 2

Core Diagnostic Criteria

The DSM-5 TR requires the following for diagnosis:

• At least 5 symptoms from a list of 9 must be present during the same 2-week period and represent a change from previous functioning 1, 2
• At least one symptom must be either:
  • Depressed mood most of the day, nearly every day 1, 3
  • Markedly diminished interest or pleasure in all or almost all activities (anhedonia) 1, 3

The Nine DSM-5 Symptoms

1. Depressed mood most of the day, nearly every day 1, 2
2. Anhedonia - markedly diminished interest or pleasure in activities 1, 2
3. Weight/appetite changes - significant weight loss or gain (>5% body weight in a month), or decrease/increase in appetite 1
4. Sleep disturbance - insomnia or hypersomnia nearly every day 1, 2
5. Psychomotor changes - agitation or retardation observable by others 1, 2
6. Fatigue or loss of energy nearly every day 1, 2
7. Feelings of worthlessness or excessive/inappropriate guilt 1, 2
8. Diminished ability to think or concentrate, or indecisiveness 1, 2
9. Recurrent thoughts of death, suicidal ideation, suicide attempt, or specific plan 1, 2

Critical Diagnostic Requirements

• Functional impairment must be present - symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning 1, 2
• Not attributable to substances or medical conditions - the episode is not due to physiological effects of a substance or another medical condition 1
• Not better explained by other disorders - the episode is not better explained by schizoaffective disorder, schizophrenia, or other psychotic disorders 1

Severity Classification Based on DSM-5 Criteria

Mild depression: 5-6 symptoms that are mild in intensity with minimal functional impairment 1, 2

Moderate depression: Symptom count, intensity, and impairment fall between mild and severe categories 1, 2

Severe depression: All or most of the 9 symptoms present with severe functional impairment, OR presence of any of the following high-risk features automatically classifies as severe regardless of symptom count 1, 2:

• Specific suicide plan, clear intent, or recent attempt 1, 2
• Psychotic symptoms 1, 2
• First-degree family history of bipolar disorder 1
• Marked functional impairment 1, 2

Bereavement Consideration (DSM-5 TR vs DSM-5 Difference)

• The diagnostic threshold should be raised during bereavement - depressive symptoms consistent with normative grief responses within the individual's cultural/religious context should not be diagnosed as depression 4
• Depression during bereavement is suggested by: persistence of symptoms for at least one month AND presence of extreme beliefs of worthlessness/guilt unrelated to the deceased, psychotic symptoms, suicidal ideation, or psychomotor retardation 4

Initial Treatment Approach

Severity-Based Treatment Algorithm

For mild depression (5-6 symptoms, minimal impairment):

• Initiate cognitive behavioral therapy (CBT) alone as first-line treatment - antidepressants should NOT be used for mild depression as drug-placebo differences are virtually nonexistent in this population 5

For moderate to severe depression:

• Initiate either CBT or a second-generation antidepressant (SSRI or SNRI) as first-line treatment, with choice guided by patient preference and adverse effect profiles 5
• Quantify baseline severity using PHQ-9 (scores 1-7 minimal, 8-14 moderate, ≥15 severe) or Hamilton Depression Rating Scale before initiating treatment 5, 2

Treatment Monitoring Protocol

• Assess response within 1-2 weeks of treatment initiation, monitoring for therapeutic effects, adverse effects, and emergence of suicidality 5
• Evaluate for adequate response by 6-8 weeks - if inadequate improvement, modify treatment through dose adjustment, switching agents, or adding augmentation strategies 5
• Minimum trial duration is 4-6 weeks for antidepressants before considering treatment failure 5

Critical Pitfalls to Avoid

• Do not diagnose depression based solely on symptom count - always assess all three dimensions: symptom count, intensity, AND functional impairment, as these are only moderately correlated 2, 3
• Do not prescribe antidepressants for mild depression - this represents inappropriate treatment with no demonstrated benefit 5
• Do not omit PHQ-9 item 9 (thoughts of self-harm) as this artificially lowers scores and may miss critical suicide risk 2
• Always rule out bipolar disorder - presence of first-degree family history of bipolar disorder or antidepressant-induced hypomania/mania requires mood stabilizers, not antidepressants alone 1, 6
• Do not count medication discontinuation due to side effects before 4 weeks as treatment failure when considering treatment-resistant depression 6

Symptom Pattern Recognition for Clinical Decision-Making

• Depressed mood + somatic symptoms (sleep, appetite, fatigue, psychomotor changes) suggests moderate depression with potential autonomic dysfunction and higher cardiovascular risk 3
• Anhedonia + non-somatic symptoms (worthlessness, guilt, concentration problems, suicidal thoughts) indicates severe depression with higher suicide risk requiring immediate intervention 3