Rethinking Depression

I see a lot of patients in General Practice with anxiety and depression. In fact, according to a recent survey, 6% of New Zealand adults will have experienced a high level of psychological distress in the last 4 weeks. 1 in 6 of us will be diagnosed with anxiety and/or depression at some point in our lives. Mental health issues are the third-leading cause of health problems for New Zealanders, after cancer and heart disease.

Depression can be diagnosed based on symptoms including low mood, sleep disturbances, fatigue, sense of worthlessness, inability to concentrate and make decisions, poor motivation, changes in diet ( over or under eating) and loss of interest in pleasurable activities.

Treatment usually involves anti-depressants , counselling, psychotherapy and encouraging the patient to improve nutrition, sleep, exercise and stress in their lives. However, I've recently been looking at a new approach called the '7 Models of Depression' taught by Rachel Arthur who is aNaturopath based in Australia.

Rather than working on the end point being increasing Serotonin levels in depressed patients, Rachel suggests looking beyond this at possible underlying drivers of depression from a physiological viewpoint.

The 7 Models of Depression summarised:

  1. Methylation Model. Methylation is a complex cycle which is going on in every cell of your body 24/7. It has many functions, but an important one is it's involvement in producing 'happy hormones' or neurotransmitters inn the brain. Methylation disorders are starting to be understood with the advent of Genomic testing. The commonest is the MTHFR snp which can cause a folate deficiency. Interestingly, research has shown 15-38% of depressed patients have a folate deficiency. Additionally, in a review of 1280 psychiatric cases, depression was 36% greater if a person had 2 copies of the MTHR snp. Vitamin B12 is also needed for healthy methylation, and be low for a variety of reasons. Depression was found to be twice as common in patients with B12 deficiency in a study of over 700 women. Folate and B12 level can be easily tested in General Practice.

  2. The Dysglycaemia Model This refers to the blood sugar levels in the body. Fluctuations can affect the brain's ability to produce the happy hormones Serotonin, Dopamine and GABA. There is a relationship with depression and diabetes, with a patient diagnosed with one condition being at increased risk of developing the other. Eating a whole food diet, exercising well and keeping stress levels under control will help with maintaining a steady blood glucose level. Chromium has also been shown to help in depressed patients with blood sugar issues, and particularly with carbohydrate cravings. However, please discuss this with your Doctor if you are considering starting it.

  3. Neuro-endocrine Model Our hormones are under the control of our Hypothalamic Pituitary Axis (HPA) which is a complex signalling system. The HPA can easily be disrupted and have an effect on the hormone systems. For example, high stress levels causes us to produce excess Cortisol, the 'survival' hormone. This can lead to prolonged raised Cortisol levels due to failure in the feedback mechanism. Chronically high Cortisol levels cause insomnia, affect our decision making ability and cognition, and affect our circadian rhythms. Fluctuations in our sex hormones can also play a role in depression. Oestrogen is the body's natural mood stabiliser and works as an anti depressant and anti anxiety hormone alongside Progesterone. Progesterone is also important for helping us sleep, and Testosterone contributes to a sense of well-being and self-confidence. Healthy levels of these hormones are important in considering depression.

  4. Pyrrole Model Kryptopyrrole disorder is a biochemical imbalance which results in an abnormality in haemoglobin synthesis. It is caused by the over production of hydroxyhempyrolin(HPL) ,which binds to zinc and vitamin B6. This is significant as both zinc and B6 are required for neurotransmitter production for healthy mood. The testing kit for Pyrrole disorder looks for pyrroles in the urine. Interestingly, 15-30% of Schizophrenic patients have pyrroluria.

  5. Inflammation Model There is a large body of research linking inflammation with depression. Inflammatory markers such as CRP in the blood are often elevated in depressed patients. Inflammation influences the HPA and brain neurotransmitter production and is thought to play a role in depression. Eating a whole food , anti-inflammatory diet , reducing stress, improving sleep and exercising, even just a short walk daily, will all help with inflammation and mood.

  6. Monamine Model This is looking at individual neurotransmitters which only contain one amine group. Serotonin is known as 'the happy hormone' and Prozac and other antidepressants aim to increase Serotonin levels. Abnormalities of other monoamine neurotransmitter levels can also contribute to depression. For example low Dopamine levels can cause poor motivation, lack of physical or mental energy, low lidido, poor self esteem and cravings for carbohydrates and stimulants. It is best to have levels checked with a Urinary Organics acid test which can be organised by a Naturopath.

  7. The Toxicity Model Heavy metal toxicity can affect brain chemistry and neurotransmitters synthesis ,resulting in anxiety and depression. Mercury, lead, cadmium and arsenic are common neurotoxic metals. Research has shown an association for example with raised lead levels and panic disorder and major depression. Heavy metal levels wouldn't be my first line of investigation in a depressed patients, but it is worth considering if there is a clear history of heavy metal exposure or a patient has treatment -resistant depression.