A patient presents with severe sadness for nearly two weeks, decreased motivation, and hypersomnia. What is the most likely diagnosis?

Major Depressive Disorder (MDD)

The most likely diagnosis is Major Depressive Disorder (MDD), as the patient meets the core diagnostic criteria with severe sadness (depressed mood), decreased motivation (loss of interest/pleasure), and hypersomnia for nearly two weeks 1, 2.

Diagnostic Criteria

To diagnose MDD, the patient must have at least 5 of 9 symptoms present during the same 2-week period, with at least one being either depressed mood or loss of interest/pleasure 1, 2. This patient clearly presents with:

1. Severe sadness = depressed mood most of the day, nearly every day
2. Decreased motivation = markedly diminished interest or pleasure in activities
3. Sleeping all the time = hypersomnia nearly every day

These three symptoms alone represent 3 of the required 5 criteria. The additional symptoms to assess include:

• Significant weight changes or appetite disturbance
• Psychomotor agitation or retardation
• Fatigue or loss of energy (likely present given the hypersomnia)
• Feelings of worthlessness or inappropriate guilt
• Diminished ability to think, concentrate, or indecisiveness
• Recurrent thoughts of death or suicidal ideation

Critical Assessment Points

Immediately assess for suicidal ideation - this is non-negotiable given the diagnosis of MDD 1. Ask directly about:

• Recurrent thoughts of death
• Suicidal ideation with or without a plan
• Any suicide attempts or specific plans

Rule out other causes before finalizing the diagnosis 1:

• The symptoms must NOT be due to substance effects (drugs, medications) or medical conditions (particularly hypothyroidism)
• The symptoms must NOT be better explained by bereavement (unless persisting >2 months or featuring marked functional impairment, worthlessness, suicidal ideation, or psychomotor retardation)
• Ensure symptoms are NOT part of a mixed episode (manic and depressive features)

Verify functional impairment - the symptoms must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning 1, 2.

Special Consideration: Atypical Features

The presence of hypersomnia with decreased motivation warrants consideration of atypical depression, which may have distinct biological underpinnings and treatment implications 3, 4, 5. Atypical features include:

• Hypersomnia (present in this patient)
• Increased appetite or weight gain (assess for this)
• Leaden paralysis or heavy feelings in limbs
• Interpersonal rejection sensitivity

Recent evidence suggests that patients with hypersomnia in depression may have decreased motivational and interpersonal communication capacities compared to those with insomnia 4. These patients may respond better to medications targeting noradrenaline and dopamine systems rather than SSRIs alone 5.

Immediate Next Steps

Refer to mental health specialist - recognition of depression should trigger immediate referral to a mental health care provider skilled in addressing this condition 1.

Begin monitoring within 1-2 weeks if pharmacotherapy is initiated, specifically assessing for 2:

• Suicidal thoughts and behaviors (highest risk in first 1-2 months)
• Agitation, irritability, or unusual behavioral changes
• Therapeutic response and adverse effects

Modify treatment if inadequate response within 6-8 weeks of therapy initiation 2.

Common Pitfalls to Avoid

• Do not dismiss hypersomnia as mere fatigue - it is a distinct diagnostic criterion and may indicate atypical features requiring different treatment approaches 5, 6
• Do not delay suicide assessment - this must be done immediately, as the risk is highest early in treatment 2, 7
• Do not overlook medical causes - particularly hypothyroidism, which can mimic depression with hypersomnia 1
• Do not assume functional symptoms rule out depression - severe functional impairment with somatic symptoms can represent atypical depression even when classic mood symptoms are less prominent 8