Depression — NZ Condition Guide | KiwiMeds

What is Depression?

Depression is a common mental health condition that causes persistent feelings of sadness, emptiness, or hopelessness that interfere with daily life. It is more than just feeling sad for a few days — depression affects how you think, feel, and function. Around one in six New Zealanders will experience depression at some point in their lives. It is a medical condition, not a character flaw or weakness, and it responds well to treatment.

Symptoms

Depression symptoms vary from person to person but commonly include persistent low mood or sadness, loss of interest or pleasure in activities you used to enjoy, changes in appetite and weight, sleep problems (sleeping too much or too little), fatigue and low energy, difficulty concentrating or making decisions, feelings of worthlessness or excessive guilt, and in severe cases, thoughts of death or suicide. If you or someone you know is having thoughts of suicide, contact Lifeline NZ on 0800 543 354 or text 4357.

Causes and Risk Factors

Depression is caused by a combination of genetic, biological, psychological, and social factors. There is no single cause. Risk factors include family history of depression, previous episodes of depression, stressful life events (bereavement, relationship breakdown, job loss), chronic health conditions, certain medications, substance use, trauma, and social isolation. In New Zealand, higher rates of depression are seen in young people, Māori, and people experiencing socioeconomic hardship.

Diagnosis

Depression is diagnosed by a doctor or mental health professional based on your symptoms and how long they have lasted. There is no blood test for depression, but your GP may order tests to rule out physical causes (such as thyroid problems). Your GP may use a questionnaire such as the PHQ-9 to assess severity. Be honest with your doctor — the more they understand what you are experiencing, the better they can help.

Treatment Options in New Zealand

Depression treatment in NZ is effective. Mild depression is often treated with talking therapies (counselling, CBT) and lifestyle changes. Moderate to severe depression usually benefits from a combination of talking therapy and antidepressant medication. Pharmac-funded antidepressants include SSRIs (fluoxetine, sertraline, citalopram, escitalopram), SNRIs (venlafaxine), and others. Access to free or subsidised talking therapy is available through your GP, employee assistance programmes (EAP), and the government-funded Integrated Primary Mental Health and Addictions programme.

NZ-Specific Information

In New Zealand, mental health services have been a focus of significant investment. Your GP is the first point of contact and can provide a Mental Health and Wellbeing Assessment, prescribe antidepressants, and refer to community mental health services. The Government funds free or low-cost counselling through Te Whatu Ora. Key NZ resources include depression.org.nz, the Lowdown (for young people), Lifeline (0800 543 354), and the Mental Health Foundation of NZ.

Frequently Asked Questions

How long does it take for antidepressants to work? Most antidepressants take 2–4 weeks to start working, with full benefit at 6–8 weeks. It is important to keep taking them even if you do not feel better straight away. Will I need to take antidepressants forever? Many people take them for 6–12 months and then taper off successfully. Some people with recurrent depression benefit from longer-term treatment. Are antidepressants addictive? No, antidepressants are not addictive — but you should not stop them suddenly, as this can cause discontinuation symptoms. Always reduce the dose gradually under medical guidance.

Supplements That May Support Management

⚠️ Important: The supplements listed below have varying levels of clinical evidence. They are not a substitute for prescribed medications and should only be considered as adjunctive support under the guidance of a qualified healthcare professional. Always inform your GP or pharmacist before commencing any supplement, as interactions with prescribed medicines are possible.

• Omega-3 Fatty Acids (EPA-dominant formulations) — EPA-dominant omega-3 supplementation (EPA:DHA ratio ≥2:1) has the strongest evidence base among supplements for depression, with meta-analyses supporting adjunctive benefit, particularly at doses of 1–2 g EPA/day. Proposed mechanisms include modulation of neuroinflammation and serotonin receptor function.
• Vitamin D — Vitamin D deficiency is strongly associated with depressive symptoms. Supplementation in deficient individuals (as confirmed by serum 25-OH vitamin D testing) can meaningfully improve mood outcomes. Standard supplementation: 1000–2000 IU daily.
• Folate/Methylfolate — Low folate status impairs monoamine neurotransmitter synthesis. L-methylfolate (the active form) may be particularly beneficial as an adjunct to antidepressant pharmacotherapy, especially in those with MTHFR gene variants affecting folate metabolism. Standard dose: 400 mcg–1 mg/day.
• S-Adenosylmethionine (SAMe) — SAMe is a methyl donor involved in monoamine synthesis. Randomised controlled trials support its use as both monotherapy for mild-moderate depression and as augmentation to antidepressants. Doses typically range from 400–1600 mg/day. Caution: may precipitate mania in bipolar disorder.
• Zinc — Zinc deficiency is more prevalent in depression, and zinc supplementation as an adjunct to antidepressant therapy has demonstrated modest improvements in depressive symptoms in several trials, likely via NMDA receptor modulation.

Relevant Vaccinations

Individuals living with depression may benefit from the following vaccinations. Please discuss your vaccination status with your GP or practice nurse, as eligibility and funding through the New Zealand National Immunisation Schedule may apply.

• Influenza (annual) — People with depression may have reduced immune function and healthcare engagement, increasing vulnerability to influenza complications. Annual vaccination is recommended.
• COVID-19 — Post-COVID mental health deterioration is well documented. Maintaining COVID-19 vaccination may reduce the risk of post-acute sequelae including neuropsychiatric symptoms.
• HPV (if age-eligible) — Ensuring age-appropriate vaccinations are up to date is an important component of holistic preventive healthcare in people with depression, who may have gaps in preventive health engagement.

Dietary Guidance

Evidence-based dietary modifications play a meaningful role in the management of depression. The following foods are generally recommended as part of a balanced, condition-appropriate diet. A referral to a registered dietitian may be beneficial for personalised nutritional planning.

• Oily fish (salmon, sardines, mackerel) — The primary dietary source of EPA and DHA omega-3 fatty acids, with the strongest nutritional evidence base in depression. Aim for at least 2 servings per week.
• Fermented foods (kefir, yoghurt, kimchi) — Support gut microbiome diversity and serotonin precursor production via the gut-brain axis. A Mediterranean dietary pattern inclusive of fermented foods has been associated with lower rates of depression in prospective studies.
• Leafy green vegetables (spinach, kale, rocket) — Rich in folate, magnesium, and iron — micronutrients with established roles in neurotransmitter synthesis and energy metabolism relevant to mood regulation.
• Legumes and whole grains — Provide steady glucose release, avoiding reactive hypoglycaemia which can exacerbate low mood. Also high in B vitamins essential for nervous system function.
• Berries and colourful fruits — Rich in polyphenols and anthocyanins with evidence supporting reduced neuroinflammation — a key pathway in the pathophysiology of depression.
• Limit ultra-processed foods and refined sugars — High consumption of ultra-processed foods is independently associated with increased depression risk in multiple large cohort studies, likely via inflammatory and gut microbiome mechanisms.

Related Conditions & Medications

Related medications: Sertraline. Related conditions: Anxiety.