St John’s wort is one of the best known herbal medicines used to treat low mood and depression. When held up to the light, its yellow petals reveal numerous pinpoint red glands which contain a fluorescent dye. This dye contains numerous substances with a natural, antidepressant action, including hypericin, hyperforin and pseudohypericin.
St John’s wort for depression
St John’s wort works in a different way to the prescribed serotonin re-uptake inhibitor (SSRI) antidepressants. Rather than just increasing brain levels of the neurotransmitter, serotonin, it has a more generalised action and inhibits the re-uptake of serotonin plus noradrenaline, dopamine, gamma-aminobutyric acid (GABA) and L-glutamate. No other antidepressant shows such a broad range of action, and it has also been used to support withdrawal in smoking cessation, alcohol and drug addiction, and to treat anxiety and compulsive behaviour.
A recent (2017) analysis of data from 27 studies, involving over 3808 people with mild to moderate depression, compared the effectiveness of St John’s wort with that of prescribed SSRIs. In studies that lasted from 4 to 12 weeks, St John’s wort was found to be equally effective in relieving symptoms, and achieving remission with significantly fewer side effects and rates of discontinuation.
Analysis of symptoms suggests that St John’s wort speeds the recovery from depression in a general manner, improving all investigated symptoms and signs associated with low mood. St John’s wort usually lifts depression within two weeks of starting treatment, and the optimum effect is reached within six weeks. Three out of four people experience a marked improvement within five weeks, with one in three becoming symptom-free.
St John’s wort and menopause
St John’s wort is more effective than placebo in treating menopausal symptoms after 8 weeks treatment. It can also lift an associated low sex drive. In 111 post-menopausal women with low sex drive, low mood and physical exhaustion, taking St John’s wort for three months helped 60% regain their sex drive. Eighty-two per cent also suffered less irritability, anxiety, low mood, hot flushes, sweating and disturbed sleep. Women taking St John’s wort also report increased self-esteem, self-confidence and self-respect.
St John’s wort and pre-menstrual syndrome
Low mood often forms part of the PMS complex, and several small studies show that St John’s wort can significant improve overall premenstrual syndrome scores, reduce crying, low mood and nervous tension. St John’s wort also significantly improves the most common physical and behavioural symptoms of PMS such as breast swelling or tenderness, tiredness, sleep difficulties, headache, irritability, mood swings and depression.
St John wort dose
Select extracts standardized to contain at least 0.3 per cent hypericin or 3% hyperforin: 250 mg to 300mg, three times a day. Stronger versions supplying 900 mg are also available if required.
St John’s Wort is best taken with food. Avoid alcohol.
St John wort side effects
Research has confirmed the good tolerability of St John’s wort extract and a low frequency of adverse events – similar to that seen with placebo. Side effects are significantly less likely than with standard anti-depressants. Those reported include indigestion, allergic reactions, restlessness and tiredness or fatigue, each in fewer than 1% of people.
St John wort interactions
If you are taking prescribed medications, it is important to check with a pharmacist for possible drug interactions before starting to take St John’s wort.
Do not take together with prescribed antidepressant drugs, including SSRIs or tricyclic antidepressants. Other interactions currently recognised between St John’s wort (Hypericum perforatum) and prescribed drugs are with oral contraceptives, warfarin, cyclosporin, anticonvulsants, digoxin, theophylline, HIV protease inhibitors, triptans, some statins, and some medicines used to treat high blood pressure, migraine and cancer. For a full list of known st John’s wort drug interactions, you can read a typical St John’s wort Patients information leaflet HERE.
Those who are sun-sensitive or on medications that cause photosensitivity (eg tetracycline, chlorpromazine) should avoid direct skin exposure to sunlight, especially if fair-skinned. However, there are no reports of skin sensitivity on exposure to sunlight (photosensitisation) in usual therapeutic doses.