8.1 Mood & Anxiety Disorders

Mood and Anxiety Disorders in General Practice

Depressive and anxiety disorders represent the most common psychiatric presentations in primary care. Family physicians must be proficient in recognizing diagnostic criteria, selecting appropriate pharmacotherapy, monitoring for side effects, and initiating psychotherapeutic referrals.

Major Depressive Disorder (MDD)

DSM-5 Diagnostic Criteria

To diagnose Major Depressive Disorder (MDD), a patient must exhibit five (5) or more of the following symptoms during the same 2-week period, representing a change from previous functioning. At least one symptom must be either (1) depressed mood or (2) loss of interest or pleasure (anhedonia):

1. Depressed mood most of the day, nearly every day (indicated by subjective report or observation).
2. Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day (anhedonia).
3. Significant weight loss when not dieting, or weight gain, or decrease or increase in appetite nearly every day.
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 nearly every day.
8. Diminished ability to think or concentrate, or indecisiveness, nearly every day.
9. Recurrent thoughts of death, recurrent suicidal ideation without a specific plan, or a suicide attempt or plan.

The mnemonic SIGECAPS is used for clinical screening:

• Sleep disturbances (insomnia/hypersomnia)
• Interest (anhedonia)
• Guilt (worthlessness/excessive guilt)
• Energy (fatigue/loss of energy)
• Concentration deficits (indecisiveness)
• Appetite changes (weight loss/gain)
• Psychomotor change (agitation/retardation)
• Suicidal ideation

Symptoms must cause clinically significant distress or functional impairment and must not be attributable to the physiological effects of a substance or another medical condition (e.g., hypothyroidism). Crucially, there must have never been a manic or hypomanic episode (which indicates Bipolar Disorder).

Screening for MDD is commonly done using the Patient Health Questionnaire-2 (PHQ-2) as an initial screen, followed by the PHQ-9 if the screen is positive. A PHQ-9 score of 10 or greater indicates moderate-to-severe depression and typically warrants clinical intervention.

Selective Serotonin Reuptake Inhibitors (SSRIs)

SSRIs are the first-line pharmacotherapeutic choice for MDD and anxiety disorders due to their safety profile and tolerability.

Common Agents

• Fluoxetine: Longest half-life (active metabolite has a half-life of 1-2 weeks), ideal for patients with poor compliance. Requires a 5-week wash-out period before initiating an MAOI.
• Sertraline: Safest post-myocardial infarction; associated with higher rates of gastrointestinal side effects (e.g., diarrhea).
• Escitalopram / Citalopram: Highly selective. Citalopram has a dose-dependent risk of QT prolongation (maximum recommended dose is 40 mg/day, or 20 mg/day in patients >60 years).
• Paroxetine: Shortest half-life, sedating, highly anticholinergic, associated with weight gain and a severe discontinuation syndrome. Avoid in pregnancy due to cardiac malformation risks.

When initiating SSRI therapy, patients must be counseled that clinical improvement is typically delayed, taking between 4 to 6 weeks for full therapeutic onset, although some response may be observed at 2 weeks. Adequate trials require 4–8 weeks at therapeutic doses before adjusting therapy.

Adverse Effect Profile and Clinical Management

• Short-Term Side Effects: Nausea, diarrhea, headache, mild anxiety, and sleep disturbances. These typically resolve within 1-2 weeks.
• Long-Term Side Effects: Sexual dysfunction (delayed ejaculation, anorgasmia) occurs in 50-70% of patients and is a leading cause of non-adherence. Weight gain is also common.
• Suicide Risk: A black-box warning exists for an increased risk of suicidal ideation and behavior in patients under 25 years during the initial 4-6 weeks of therapy.
• Serotonin Syndrome: A life-threatening emergency caused by excessive serotonergic activity. It presents with a triad of altered mental status (agitation, confusion), autonomic hyperactivity (tachycardia, hyperthermia, diaphoresis), and neuromuscular abnormalities (hyperreflexia, clonus, tremor). Immediate discontinuation of serotonergic agents, supportive care, and cyproheptadine (serotonin antagonist) for severe cases are required.
• Wash-out Periods: When switching from an SSRI to an MAOI, a 2-week wash-out period is required (5 weeks for fluoxetine).

Generalized Anxiety Disorder (GAD)

DSM-5 Diagnostic Criteria

Generalized Anxiety Disorder is characterized by:

• Excessive anxiety and worry occurring more days than not for at least 6 months, about multiple events or activities.
• Difficulty controlling the worry.
• Associated with three (3) or more of the following six symptoms:
  1. Restlessness or feeling keyed up or on edge.
  2. Being easily fatigued.
  3. Difficulty concentrating or mind going blank.
  4. Irritability.
  5. Muscle tension.
  6. Sleep disturbance.

To monitor severity and treatment response, the Generalized Anxiety Disorder 7-item (GAD-7) scale is recommended, where scores of 5, 10, and 15 represent mild, moderate, and severe anxiety, respectively.

GAD Management

• First-line pharmacotherapy: SSRIs (e.g., escitalopram, sertraline) or SNRIs (e.g., duloxetine, venlafaxine).
• First-line psychotherapy: Cognitive Behavioral Therapy (CBT).
• Second-line/Adjunctive: Buspirone (slow onset of 2-4 weeks, no abuse potential).
• Benzodiazepines: Restricted to short-term, adjunctive use during antidepressant initiation to prevent tolerance and dependence.

Panic Disorder

Clinical Presentation

Panic disorder is characterized by recurrent, unexpected panic attacks. A panic attack is an abrupt surge of intense fear reaching a peak within minutes, with at least 4 of 13 somatic or cognitive symptoms (e.g., palpitations, sweating, chest pain, dyspnea, choking, dizziness, fear of dying). At least one attack must be followed by 1 month or more of persistent concern about additional attacks or maladaptive behavioral changes to avoid them.

Clinical Management

• Acute Management: Short-acting benzodiazepines (e.g., lorazepam or alprazolam) provide rapid relief but must be limited.
• Long-Term Management:
  • SSRIs are the first-line pharmacotherapy choice. Start at low doses (half the starting dose for depression) because panic patients are sensitive to the initial activating side effects.
  • CBT is highly effective and focuses on interoceptive exposure and cognitive restructuring.