According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), Major Depressive Disorder (MDD) is characterized by the presence of five or more specific symptoms during the same two-week period, representing a change from previous functioning. At least one of the symptoms must be either depressed mood or loss of interest or pleasure.

Diagnostic Criteria for Major Depressive Disorder:

1. Depressed mood most of the day, nearly every day, as indicated by subjective report (e.g., feels sad, empty, hopeless) or observation made by others (e.g., appears tearful).
2. Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day.
3. Significant weight loss when not dieting, 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 a specific plan for committing suicide.
   

   Screening

   The following two questions can be used to screen for depression

   • ‘During the last month, have you often been bothered by feeling down, depressed or hopeless?’
   • ‘During the last month, have you often been bothered by having little interest or pleasure in doing things?’

   A ‘yes’ answer to either of the above should prompt a more in depth assessment.

   Assessment:

   Hospital Anxiety and Depression (HAD) scale and the Patient Health Questionnaire (PHQ-9).

   • a score < 16 on the PHQ-9: less severe depression
   • a score of ≥ 16 on the PHQ-9: severe depression

   Management of less severe depression – no medication unless patient preference

   Treatment options, listed in order of preference by NICE

   • guided self-help
   • group cognitive behavioural therapy (CBT)
   • group behavioural activation (BA)
   • lifestyle advice: exercise, healthy diet

   Management of more severe depression: CBT+SSRI

   • a combination of individual cognitive behavioural therapy (CBT) and an antidepressant

   Medication:

   • SSRIs are first-line medications in depression and are generally e.g. citalopram fluoxetine, or sertraline
     • Fluoxetine – drug of choice in children and adolescents
     • There is a lag period of 4 – 6 weeks before effects are seen
     • Should be continued for at least 6 months following remission of symptoms
   • Second-Line Treatment:

   If there is an inadequate response to SSRIs, or if SSRIs are not suitable, other classes of antidepressants may be considered, such as:

   • • Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): e.g., venlafaxine, duloxetine.
     • Mirtazapine: An antidepressant with a different mechanism of action, often considered when sedation is beneficial.
   • Third-Line Treatment:
   • Tricyclic Antidepressants (TCAs): e.g., amitriptyline, clomipramine. These may be considered if other treatments are ineffective, but they have a higher side-effect burden and are generally less well-tolerated.

    

   • ECT should only be used as an acute treatment of severe depression that is  and when a  is required, or when .

   life-threatening

   rapid response

   other treatments have failed

   • Dose of antidepressant should be reduced (but not stopped) prior to ECT

   LINK to ECT:

   Electroconvulsive Therapy (ECT) is a medical treatment used primarily for severe mental health conditions, particularly when other treatments have been ineffective. It involves delivering controlled electrical currents to the brain to induce a brief seizure under general anesthesia.

   Indications for ECT

   ECT is used for:

   1. Severe Depression: Particularly with suicidal ideation, psychotic features, or when rapid response is needed.
   2. Treatment-Resistant Depression: When medication and psychotherapy have failed.
   3. Mania: Severe manic episodes in bipolar disorder.
   4. Schizophrenia: Catatonic or treatment-resistant cases.
   5. Catatonia: Marked psychomotor retardation or unresponsiveness.