Teen girls, the pill and mood: is hormonal birth control driving antidepressant use and thyroid problems?

What the big studies found

The study that put this on the map followed over a million Danish women and found that those using hormonal contraception were more likely to be prescribed a first antidepressant or diagnosed with depression than non-users. The relative increase was largest in adolescents aged 15 to 19: around 1.8 times higher for combined pill users, with progestogen-only methods also showing increases (Skovlund et al., 2016). A follow-up study from the same group found a higher rate of first suicide attempts among hormonal contraceptive users, again most marked in adolescents (Skovlund et al., 2018).

Other work points in a similar direction. A Swedish study of 800,000 women found hormonal contraception was associated with psychotropic drug use in adolescent girls but not in adult women (Zettermark et al., 2018). A Dutch cohort that followed girls through adolescence found that pill users had more depressive symptoms at age 16 — particularly crying, sleeping more and eating problems — but not at older ages (de Wit et al., 2020). And a UK Biobank analysis found a higher risk of depression in the first two years of pill use, especially when use began in adolescence (Johansson et al., 2023).

In 2018, European regulators updated product information for hormonal contraceptives to include warnings about depressed mood and suicidal behaviour.

The associations are real and consistent enough to take seriously — especially for teenagers, and especially in the first months of use.

What remains uncertain

Association isn't causation, and there are several reasons the numbers could overstate the pill's role:

• Absolute risk is small. In the Danish study, roughly 2.2 per 100 users a year started an antidepressant, compared with about 1.7 per 100 non-users. That is a meaningful difference across a population, but most young women on the pill do not develop depression.
• The pill is often prescribed for things that are themselves linked to low mood: painful or heavy periods, PMS, acne and conditions like endometriosis and PCOS.
• Adolescence is when depression rates rise anyway, and girls on the pill have more contact with doctors, so mood problems may be noticed and treated more often.
• Randomised trials, which can test cause and effect, are mostly in adults and generally show small average mood effects — with some women feeling worse and others better (Lundin et al., 2017).

Is the pill driving the rise in teenage antidepressant use?

This is where the claim goes further than the evidence. The research suggests hormonal contraception may contribute to mood problems for some adolescents, and that this deserves much more attention than it gets. It does not show that the pill is the main driver of rising antidepressant prescriptions among teenagers, which have many likely contributors. The fairest summary is: for some girls, the pill may be part of the picture, and it should be on the list of things to ask about — not the only thing.

Why a developing brain might be more sensitive

The adolescent brain is still developing, and sex hormones are part of that process. Hormonal contraceptives work by suppressing the body's own cycle of estradiol and progesterone and replacing it with steady doses of synthetic hormones. Researchers have pointed out how little we know about the effects of this on the brain, particularly in young users (Pletzer & Kerschbaum, 2014). The combined pill also raises sex hormone-binding globulin and lowers free testosterone (Zimmerman et al., 2014), which some women notice as changes to libido, energy or mood. These are plausible mechanisms, not proven explanations.

Many books and clinicians in women's health write about mood and hormonal contraception. If you come across them, weigh any non-medical source against the research cited in this article, and discuss what you read with a qualified practitioner before making decisions.

The pill and the thyroid: what's actually going on

The thyroid part of the claim is mostly about blood tests. Oestrogen in the combined pill increases thyroxine-binding globulin, the protein that carries thyroid hormone in the blood. That raises total T4 levels, even though free T4 — the active, unbound hormone — usually stays in range (Wiegratz et al., 2003; Raps et al., 2014). If a young woman on the pill has a thyroid test, it is worth making sure free T4 and TSH are measured, and that the person interpreting it knows she is on the pill.

There isn't good evidence that the pill causes thyroid disease. What is more plausible is an indirect effect on the nutrients the thyroid needs. Reviews have reported that oral contraceptive use is associated with lower levels of several nutrients, including vitamins B2, B6 and B12, folate, magnesium, zinc and selenium (Palmery et al., 2013). Selenium and zinc are important for thyroid function, and B vitamins for mood. Much of this evidence is older and observational, so it is a reason to check and eat well rather than a reason to panic.

How to weigh it up together

The pill is an effective contraceptive and, for some girls, a genuine relief from painful, heavy or disruptive periods. The decision isn't 'pill good' or 'pill bad'. It is about what is right for this young woman, now.

• Be clear on the reason. Is it contraception, period pain, acne, heavy bleeding or a diagnosed condition? Different reasons can point to different options.
• Ask about alternatives: different pill formulations, the copper coil, a hormonal coil (which uses a lower dose but still has some systemic effect) or non-hormonal approaches to period symptoms.
• Track mood before and after. A simple daily mood score for a month or two before starting and for the first three to six months on it gives you real information.
• Know the warning signs: new or worsening low mood, anxiety, irritability, losing interest in things, or any thoughts of self-harm. Book a review promptly if they appear.
• Support the foundations: regular meals with protein, iron-rich foods (especially with heavy periods), sleep, movement and time outdoors. Ask for ferritin, B12, folate and vitamin D to be checked if she is tired or low.
• Never stop suddenly without guidance. Stopping can mean an immediate pregnancy risk and a return of the symptoms the pill was treating. Plan any change with the prescriber.

A note for parents

If you are a parent reading this, the most protective thing you can offer is probably not a firm opinion about the pill. It is a relationship in which your daughter feels able to tell you how she is feeling, what she has been prescribed and whether something doesn't feel right. Fear-based conversations tend to push young people towards silence.

It also helps to know that in the UK, young people under 16 can receive confidential contraceptive advice and treatment if a clinician judges them able to understand the decision. That confidentiality exists to keep them safe. Rather than working around it, encourage her to bring her questions to her clinician — or offer to go with her if she would like you there — and make it clear that changes in mood are always worth mentioning, never an overreaction.

If she is struggling right now

If you are having thoughts of harming yourself or ending your life, please reach out now: in the UK call Samaritans on 116 123 (free, 24/7); in South Africa call the SADAG suicide crisis line on 0800 567 567; or contact your local emergency services. You deserve support today, not after the next appointment.

Before you act on any of this

This article is for education and general information only. It isn't medical advice, it can't diagnose or treat any condition, and it doesn't replace a consultation with your own doctor or a qualified practitioner who knows your history. Please don't start, stop or change any medication, hormone or supplement because of something you've read here — take your questions to the person responsible for your care.

Contraception choices are personal and medical. Any change to a prescribed contraceptive should be planned with a doctor, nurse or sexual health service.

References

• de Wit, A.E., Booij, S.H., Giltay, E.J., Joffe, H., Schoevers, R.A., & Oldehinkel, A.J. (2020). Association of use of oral contraceptives with depressive symptoms among adolescents and young women. JAMA Psychiatry, 77(1), 52–59.
• Johansson, T., Vinther Larsen, S., Bui, M., Ek, W.E., Karlsson, T., & Johansson, Å. (2023). Population-based cohort study of oral contraceptive use and risk of depression. Epidemiology and Psychiatric Sciences, 32, e39.
• Lundin, C., Danielsson, K.G., Bixo, M., et al. (2017). Combined oral contraceptive use is associated with both improvement and worsening of mood in the different phases of the treatment cycle — a double-blind, placebo-controlled randomized trial. Psychoneuroendocrinology, 76, 135–143.
• Palmery, M., Saraceno, A., Vaiarelli, A., & Carlomagno, G. (2013). Oral contraceptives and changes in nutritional requirements. European Review for Medical and Pharmacological Sciences, 17(13), 1804–1813.
• Pletzer, B.A., & Kerschbaum, H.H. (2014). 50 years of hormonal contraception — time to find out, what it does to our brain. Frontiers in Neuroscience, 8, 256.
• Raps, M., Curvers, J., Helmerhorst, F.M., et al. (2014). Thyroid function, activated protein C resistance and the risk of venous thrombosis in users of hormonal contraceptives. Thrombosis Research, 133(4), 640–644.
• Skovlund, C.W., Mørch, L.S., Kessing, L.V., & Lidegaard, Ø. (2016). Association of hormonal contraception with depression. JAMA Psychiatry, 73(11), 1154–1162.
• Skovlund, C.W., Mørch, L.S., Kessing, L.V., Lange, T., & Lidegaard, Ø. (2018). Association of hormonal contraception with suicide attempts and suicides. American Journal of Psychiatry, 175(4), 336–342.
• Wiegratz, I., Kutschera, E., Lee, J.H., et al. (2003). Effect of four different oral contraceptives on various sex hormones and serum-binding globulins. Contraception, 67(1), 25–32.
• Zettermark, S., Perez Vicente, R., & Merlo, J. (2018). Hormonal contraception increases the risk of psychotropic drug use in adolescent girls but not in adults: a pharmacoepidemiological study on 800 000 Swedish women. PLoS One, 13(3), e0194773.
• Zimmerman, Y., Eijkemans, M.J.C., Coelingh Bennink, H.J.T., Blankenstein, M.A., & Fauser, B.C.J.M. (2014). The effect of combined oral contraception on testosterone levels in healthy women: a systematic review and meta-analysis. Human Reproduction Update, 20(1), 76–105.