Understanding Depression

Everyone feels down sometimes. Sadness is a normal, healthy response to loss, disappointment, or stress — it comes in waves, it usually has a cause you can name, and it lifts. Major depression is different. It's a persistent state that changes how you feel, how your body works, and how you think about yourself and the future — and it doesn't simply pass when circumstances improve.

Clinically, depression is a mood disorder: a recognized medical condition with diagnostic criteria, known biological correlates, and effective treatments. The hallmark isn't just feeling sad. For many people the defining experience is anhedonia — the loss of interest or pleasure in things that used to matter. Food, friends, work, sex, hobbies: all can go flat and gray.

This distinction matters because it changes what helps. You can't "snap out of" depression any more than you can will away asthma — and being told to try is one of the loneliest parts of the illness. Understanding it as a health condition is the first step toward treating it like one.

"Depression" is an umbrella over several related conditions. The differences matter because they point toward different treatments.

Major depressive disorder (MDD)

The most familiar form: one or more major depressive episodes — discrete periods of at least two weeks where symptoms are present nearly every day. Episodes can be a one-time event or recurrent across a lifetime.

Persistent depressive disorder (dysthymia)

A lower-grade but chronic depression lasting two years or more(one year in children and teens). The symptoms may be less intense than a full episode, but their persistence is wearing — many people describe it as having felt "this way for as long as I can remember." Episodes of major depression can occur on top of it (sometimes called "double depression").

Seasonal pattern (seasonal affective disorder)

Depression that reliably arrives and lifts with the seasons — most commonly beginning in fall and winter as daylight shrinks, which makes it especially relevant in northern New England. Reduced light is thought to disrupt circadian rhythms and serotonin regulation. Light therapy is a first-line treatment alongside the usual options.

Peripartum (postpartum) depression

A major depressive episode that begins during pregnancy or in the weeks to months after birth. It is far more than the short-lived "baby blues" — it's a serious, treatable condition affecting roughly 1 in 7 new parents, and it can affect fathers and non-birthing partners too. It deserves prompt care; effective treatments exist and are compatible with parenting.

Clinicians use the criteria in the DSM-5-TR(the American Psychiatric Association's diagnostic manual). A major depressive episode is diagnosed when five or more of the following symptoms are present during the same two-week period, represent a change from before, and cause real distress or impairment — and at least one of them is either depressed mood or loss of interest/pleasure:

• Depressed mood most of the day, nearly every day (feeling sad, empty, or hopeless — or, in children and teens, irritable).
• Loss of interest or pleasure in almost all activities (anhedonia).
• Appetite or weight change — eating much more or much less than usual.
• Sleep change — insomnia or sleeping too much (hypersomnia).
• Slowed down or restless — observable agitation or a heavy, sluggish slowing of movement and speech.
• Fatigue or loss of energy nearly every day.
• Worthlessness or excessive guilt — often out of proportion to reality.
• Trouble concentrating, thinking, or making decisions.
• Recurrent thoughts of death or suicide, or a suicide attempt or plan.

The symptoms must not be better explained by substance use, a medical condition, or another disorder. A clinician also weighs context — a thorough assessment looks at the whole person, not just a checklist.

Screening tools like the PHQ-9 are useful for spotting depression and tracking it over time, but a score is not a diagnosis. Use it as a starting point for a conversation with a professional.

There is no single cause of depression. The best-supported way to understand it is the biopsychosocial model — biology, psychology, and social environment interacting over time. For any one person, the mix is different.

Biological factors

• Genetics.Depression runs in families; heritability is estimated around 40%. Genes load the dice but don't determine the outcome.
• Brain chemistry and circuits.Depression involves changes in neurotransmitter systems (serotonin, norepinephrine, dopamine) and in how mood-regulating brain networks function. The old "chemical imbalance" slogan is an oversimplification — the reality is a more complex story of stress, circuits, and neuroplasticity.
• Physical health. Thyroid problems, chronic illness, chronic pain, hormonal shifts, and some medications can cause or mimic depression.

Psychological factors

• Patterns of thinking — harsh self-criticism, rumination, and hopeless interpretations — can deepen and maintain low mood.
• Early experiences and learned beliefs about oneself and the world shape vulnerability.

Social and environmental factors

• Stressful life events (loss, trauma, financial strain), isolation, discrimination, and lack of support all raise risk.
• Adversity in childhood is a particularly strong predictor.

Depression is one of the most studied conditions in medicine, and the evidence is genuinely hopeful. Most people improve with treatment, and for moderate-to-severe depression, combining approaches tends to work best.

Psychotherapy

• Cognitive behavioral therapy (CBT) helps you identify and shift the thought patterns and behaviors that maintain depression. It has decades of strong evidence and gives you skills that outlast the therapy itself.
• Behavioral activation (BA)is a powerful, practical approach: depression pulls you to withdraw, which removes sources of reward and deepens the low — BA reverses the spiral by scheduling small, meaningful, values-based activities. It works even when motivation hasn't returned yet.
• Interpersonal therapy (IPT) focuses on relationships and life transitions, and is well-supported for depression.

Medication

Antidepressants — most commonly SSRIs and SNRIs — can be very effective, especially for moderate-to-severe depression. A few things worth knowing:

• They typically take 4–6 weeks to reach full effect; patience and follow-up matter.
• Finding the right medication and dose can take some trial and error — this is normal, not failure.
• They should be started and stopped with a prescriber's guidance, never abruptly.

Lifestyle and body-based approaches

• Exercise. Regular physical activity has a measurable antidepressant effect and is a meaningful part of treatment for mild to moderate depression — not a replacement for care, but a real contributor.
• Sleep, light, and routine. Stabilizing sleep and daily rhythm — and, for seasonal patterns, bright light therapy — supports recovery.

For severe or treatment-resistant depression

When standard treatments haven't worked, effective options remain, including ECT (highly effective for severe depression), TMS, and newer agents such as esketamine. These are delivered under specialist care. The key message: not responding to the first treatment does not mean depression is untreatable.

A good rule of thumb: if low mood or loss of interest has lasted two weeks or moreand is getting in the way of work, relationships, or daily life, it's worth talking to a professional. You don't have to be at rock bottom to deserve help.

Reach out sooner rather than later if you notice:

• Thoughts of death or suicide, or feeling like a burden.
• Being unable to function — missing work, school, or basic self-care.
• Using alcohol or drugs to cope.
• Symptoms that keep worsening despite your best efforts.

Start with a primary care provider, a community mental health center, or a therapist. If cost or access is a barrier, the resources below can help you find care regardless of insurance.

Meridian maintains a verified, regularly re-checked directory of New Hampshire mental health resources — community mental health centers, counselors, support groups, and crisis services.