Depression: does nutrition have an adjunctive treatment role?(VIEWPOINT)(Abstract Depression is a serious illness, affecting more than one million Australians each year. It causes significant morbidity and is a major risk factor for deliberate self-harm and suicide. Depression was traditionally viewed as a personality weakness, for which few treatment options were available. The simplistic view that depression is a personality weakness has changed in recent times. Depression is now widely recognised as a mood disorder with underlying biological (biochemical and genetic) and psychosocial causes and as such is responsive to a number of different treatments. The aim of the present paper is to review the literature related to dietary manipulation and how manipulation may assist in treating this illness. Evidence reviewed supports a potential therapeutic benefit of n-3 polyunsaturated fatty acids for the alleviation of negative symptoms associated with depression. Omega-3 polyunsaturated fatty acids, optimal omega balance, folate, tryptophan, vitamin [B.sub.6], [B.sub.12], S-adenosyl-L-methionine and Hypericum perforatum may all serve as adjuncts to psychosocial and pharmacological therapies, with positive implications for long-term prognosis. Key words: clinical nutrition, diet education, diet practice, diet therapy, fatty acid, nutritional research. INTRODUCTION The aim of the present paper is to review the literature related to depression and to elucidate how dietary manipulation might help ameliorate the effects of this illness. Clinical depression is a unipolar mood disorder characterised by a pervasive negative mood (persisting for greater than 14 consecutive days) accompanied by a generalised loss of interests, an inability to experience pleasure and suicidal tendencies. It is costly in terms of human suffering and health service use, and has severe implications on physical health. (1) Until recently, many Australians had limited knowledge and inaccurate beliefs about mental health problems, and people who suffer from depression were all too often stigmatised and ostracised from society. (1) Fortunately, this situation is now gradually changing as government and public health initiatives help to increase community awareness and understanding of depression, with the successful implementation of beyondblue and the Black Dog programme, to name a few. (2,3) The causes of depression can be biological, including genetic and biochemical causes, and psychosocial, which involves upbringing, emotional experiences, cultural and environmental influences as well as interpersonal behaviours and interactions. (4) Depression is a treatable condition, with early intervention and treatment underpinning an optimistic prognosis. Styron observed, in the account of his own depressive episode, that 'acute depression inflicts few permanent wounds'. (5) The overriding concern in very severe cases is to ensure the safety of the depressed person, both from deliberate self-injury and inappropriate risk-taking behaviour. Once stabilised, the main goal of management is to reverse the lowered mood, using a combination of non-pharmacological and pharmacological treatments. (4) Psychotherapy includes such techniques as cognitive behaviour therapy and interpersonal therapy where a person's negative thoughts, attitudes and beliefs are challenged and positively refocused. (6) Medication may prove necessary where psychotherapy alone does not elicit satisfactory results. (6) Electroconvulsive therapy, a treatment for severe refractory depression used only after psychotherapy and pharmacotherapy have failed over some time period, may prove necessary in more severe forms of depression. (6) The antidepressant drugs fall into three main groups--the tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs) and selective serotonin reuptake inhibitors and serotonin and noradrenaline reuptake inhibitors (SSRIs, SNRIs). (7) Many studies have confirmed that these drugs are effective; however, long-term use gives rise to a number of common and unpleasant side effects, such as weight gain, gastrointestinal disturbances (xerostoma, indigestion, gastric ulceration and constipation), blurred vision, drowsiness and dizziness. (7) An additional requirement when taking MAOIs is strict dietary restriction of foods containing high levels of tyramine. The list of tyramine-containing foods is extensive and includes many common foods, such as bananas, avocado, soy products, cheese, coffee and tea. (7,8) Although newer antidepressant drugs such as the SSRIs and SNRIs (with fewer side effects in the short to medium term) have been developed to reduce adverse effects, there is still considerable interest, in the medical arena to search for safe and effective alternatives. (8) This is reflected in the great deal of current research investigating the links between dietary components and the development and treatment of depression. One of the most active areas of research concerns the relationship between the omega-3 long-chain polyunsaturated fatty acids (PUFAs) and depression and the use of omega-3 fatty acid supplements in the treatment of depression. (9,10) Other nutrients and 'natural' substances identified as having potential implications in the treatment of depression are folate, tryptophan, vitamin [B.sub.6], [B.sub.12], S-adenosyl-L-methionine (SAMe) and Hypericum perforatum. (11) The aim of the present review is to investigate the adjunctive role of nutrition in the treatment of depression. PREVALENCE treatment for depression)