In their practices herbal practitioners often encounter patients who report they are depressed or have symptoms that suggest depression might be a diagnosis. In many cases these symptoms are linked to highly stressful situations (also to wider world events), in which anxiety may also strongly feature, or to grief or loss. Or they are confused with other problems, such as fatigue conditions, chronic viral or other infections and immunological conditions, so that it is sometimes difficult to assess whether the depression is or should be a distinct diagnosis. Sometimes patients will say that the doctor has said they have depression, while another response could be “so would I in that situation!” For the herbal practitioner the treatment of the patient’s ‘depression’ is generally more productive if it is seen as in the context of another problem. So one question often features: should there be distinct diagnosis of depression here, or is this person depressed as an obvious response to a challenging situation or other health issue?

The conventional psycho-medical definition of depression is enshrined in the current standard text DSM-5, the official manual of the American Psychiatric Association. This outlines criteria to make a clinical diagnosis. The individual must be experiencing five or more symptoms during the same 2-week period, at a level that generates clinically significant distress or impairment in social, occupational, or other important areas of functioning, and at least one of the symptoms should be 1 or 2.

1. Depressed mood most of the day, nearly every day.
2. Markedly diminished interest or pleasure in all, or almost all, activities (‘anhedonia’) most of the day, nearly every day.
3. Significant weight loss or weight gain, or decrease or increase in appetite nearly every day.
4. A slowdown of thought and a reduction of physical movement (observable by others).
5. Fatigue or loss of energy nearly every day.
6. Feelings of worthlessness or excessive or inappropriate guilt nearly every day.
7. Diminished ability to think or concentrate, or indecisiveness, nearly every day.
8. Recurrent thoughts of death, or a suicide attempt, or a specific plan for committing suicide.

This diagnosis makes the case for a distinct medical condition that should be treated separately from other factors. However, it excludes the result of substance abuse or another medical condition. In making this latter point it thus skirts over many everyday encounters in herbal practice.

Medicalising depression also overlooks a much wider conversation about its place in human history and society, its role historically in the religious path, the prominence ‘melancholics’ (from the Greek for ‘black bile’) have had in the creative arts, from cave paintings (often done in very dark places a very long way from the light) through Michelangelo and van Gogh, to British comics like Spike Milligan and Tony Hancock. How would the British fortunes through World War II have changed if Churchill had been cured of his depression? And what to make of the startling observation that biochemical and metabolic changes of depression are also found in animal hibernation?(3) It is the practitioner’s calling to reduce suffering wherever possible but the extent to which depression is woven into the human (and even animal) condition means that at the least approaches should avoid simplicity. Simple reliance on antidepressants may not meet all the needs of someone who is prone to depressive episodes.

However there is no doubt that in its most severe forms depression is a force to itself, accompanied by biochemical and metabolic changes in the body, and that direct antidepressant prescriptions may be important and even life-saving.

Clinically diagnosed depression can be unipolar or bipolar.

Unipolar depression

Unipolar depressive disorders are typically classified as follows in DSM-5:

• Major depressive disorder (MDD) characterised by deep sadness, apathy, irritability, disturbed sleep, disturbed appetite, weight loss, fatigue, poor concentration, guilt and persistent thoughts of death – lasting longer than 2 weeks and not linked to recent grief, substance abuse or a medical disorder.
• Dysthymic disorder, which consists of a pattern of chronic, ongoing mild depressive symptoms that are less severe than major depression.
• Seasonal affective disorder (SAD), which is related to seasonal changes. The prevalence increases with increasing latitude and it can be treated by light therapy. Symptoms include lack of energy, weight gain and carbohydrate craving.

Antidepressants were designed to treat patients experiencing MDD, especially with suicidal thoughts or exhibiting other forms of self-endangerment. The severity of some major depressive symptoms makes referring to specialist care a priority, with any herbal approaches in supportive mode (although also see the discussion on inflammatory mechanisms for some potentially more significant contributions). In this classification herbal medicine starts as potentially appropriate for mild to moderate manifestations, found in dysthymic disorders, and particularly in helping with the often accompanying anxiety.

Bipolar disorder: Formerly referred to as manic depression, there are different bipolar conditions. Each include phases of mania or hypomania alternating with depression, or euphoria with anhedonia.

Hypomania is a distinct period of abnormally and persistently increased activity or energy, inflated self-esteem or grandiosity, decreased need for sleep, talkability, distractibility, increased goal seeking, risky, inappropriate or even dangerous activities (eg unrestrained buying sprees, sexual indiscretions, or foolish business investments), that lasts most of the day for at least four consecutive days. These episodes include a noticeable change from usual behaviour and function, observable by others, though not severe enough to cause marked impairment in social or occupational functioning or to necessitate hospitalization.

Mania is diagnosed after at least a week of such symptoms and additionally when the mood disturbance is sufficiently severe to cause marked impairment in social or occupational functioning, or to necessitate hospitalization to prevent harm to self or others, or there are psychotic features.

The main categories of bipolar identified in DSM-5 are as follows.

• Bipolar I disorder. There has been at least one manic episode. The manic episode may have been preceded by and may be followed by hypomanic or major depressive episodes 
• Bipolar II disorder. There has been at least one hypomanic episode but not full mania.
• Cyclothymic disorder. At least two years of multiple periods of hypomania symptoms and periods of depressive symptoms (though less severe than major depression).
• Other types. These include, for example, bipolar and related disorders induced by certain drugs or alcohol or due to a medical condition, such as Cushing’s disease, multiple sclerosis or stroke.

Bipolar II disorder is not a milder form of bipolar I, but a separate diagnosis. While the manic episodes of bipolar I disorder can be severe and dangerous, individuals with bipolar II can be depressed for longer periods, which can cause significant impairment and its own dangers. The timing of symptoms may include additional diagnostic labels such as mixed or rapid cycling. In addition, bipolar symptoms may occur during pregnancy or change with the seasons.

Although bipolar disorder can occur at any age, typically it is diagnosed in the teenage years or early 20s. Symptoms can vary from person to person, and may vary over time.