Major depression
An episode of at least two weeks in which low mood or loss of interest and pleasure dominates most days, together with changes in sleep, appetite, energy, concentration, self-worth and sometimes thoughts of death. It is a change from the person's usual functioning, not their temperament.
What drives it
No hidden purpose: it is a shutdown state in which the reward, energy and threat systems are recalibrated towards withdrawal, often after loss, defeat, chronic stress or entrapment. Psychologically it often carries anger or grief that has turned inward into self-blame.
How it shows
Work
In high-functioning adults output often holds up for a while; what drops first is initiative and speed. Decisions take longer, emails sit unanswered, the person stops volunteering ideas and goes quiet in meetings that used to energise them. Mistakes on routine work, flat delivery, 'I'm just tired', and a new habit of saying 'whatever you think'. Weekends no longer restore them.
Relationships
Withdrawal from sex, plans and conversation; irritability is often more visible than sadness, especially in men. They stop asking about you. Small requests feel huge to them. Partners report living with someone who is 'there but not there', and often take the withdrawal personally.
Self
Things you know you value produce no pull; you go through motions and feel nothing back. Mornings are worst. Your thoughts run on guilt and worthlessness ('I'm a burden', 'I've wasted everything') and they feel like accurate observations, not moods. The future looks short and grey.
What tells it apart
Burnout: Burnout is bound to work: the person is exhausted and cynical about the job but can still enjoy a holiday, a hobby or their kids. In depression the flatness, guilt and self-loathing follow them home and into everything, and time off does not lift it.
Grief (complicated, disenfranchised, anticipatory): In grief the pain comes in waves tied to reminders of the loss, the person can still laugh at a story about the dead, and self-esteem is intact. Depression is a constant grey pressure with pervasive worthlessness ('I am bad') rather than longing ('I miss them').
ADHD in adults: ADHD inattention is lifelong, present in good moods, and the person can hyperfocus on what interests them. Depressive poor concentration has an onset, comes with lost interest in everything, and lifts when the mood lifts.
A test
Watch for a change from baseline lasting two weeks or more across both work and home (loss of pleasure, sleep or appetite change, self-blame, hopelessness), and suggest a GP or psychologist assessment when it persists, impairs functioning or includes any talk of death.
Questions to carry
- Over the last two weeks, how have sleep, appetite and pleasure changed from this person's usual self?
- When my days went flat for weeks at a time, who noticed first, and who did I let know?
How strong the research is
strong
Where it comes from
Emil Kraepelin, 1899 (within manic-depressive illness); Feighner criteria, 1972; codified as major depressive disorder in DSM-III, 1980
Sources
- Sigmund Freud, Mourning and Melancholia (1917)
- Aaron T. Beck, Cognitive Therapy and the Emotional Disorders (1976)