Introduction
Medicines such as Wegovy (semaglutide) and Mounjaro (tirzepatide) are effective for weight loss and blood sugar control. If you live with a mental health condition such as depression or anxiety, or you are taking psychiatric medication, you may wonder how these treatments could affect your wellbeing
GLP-1 medicines are not licensed to treat mental illness, but because they act on the brain as well as the gut, researchers have explored how they may influence mood.
GLP-1 Medicines and Mental Health: What the Evidence Says
How they work in the brain: GLP-1 receptors are found in areas of the brain involved in appetite, reward, and mood regulation. Studies suggest GLP-1s may influence dopamine and serotonin pathways, which are also linked to depression and anxiety (1,2).
Potential positive effects: Some patients report improved mood, confidence, and energy after weight loss. Early research suggests GLP-1s may have a role in improving depressive symptoms in certain people (3).
Concerns raised: Observational studies and safety reports have suggested possible links between GLP-1 use and depression, anxiety, or suicidal thoughts, but findings are inconsistent and may be influenced by reporting bias (4,5).
Clinical trial data: Large randomised trials such as the STEP studies have not shown higher rates of depression or suicidal thoughts compared with placebo (6).
Regulator review: The European Medicines Agency (EMA, 2024) reviewed available evidence and concluded there is no proven causal link between GLP-1 medicines and suicidal or self-injurious thoughts (7).
In summary: GLP-1s may affect brain chemicals involved in mood, but current research does not prove they cause mental health problems. Because responses vary, it’s important to monitor your mental health and stay in touch with your GP or mental health team.
What Patients Should Consider:
1.Before starting treatment
- Inform your GP or mental health professional of your intention to start using weight loss injections. If you have a history of depression, anxiety, eating disorders, or other mental health conditions, they may decide to increase frequency of reviews if they deem this necessary.
- Share a full list of medications, including antidepressants, antipsychotics, or mood stabilisers with your weight loss provider.
2. During treatment / Maintenance
- Monitor your mood, sleep, and energy levels.
- Report any new or worsening depression or anxiety to your GP promptly.
- Remember: some side-effects of GLP-1s (e.g. fatigue, nausea, appetite changes) can overlap with mental health symptoms.
3. Stopping treatment
Many patients feel mentally better after weight loss.
Some may feel anxious about maintaining results or adjusting to body image changes. If this happens, speak with your GP or mental health professional.
Lifestyle Tips to Support Mental Health
- Eat well: Include vegetables, fruit, wholegrains, lean protein, and omega-3 sources. Limit processed foods and sugary drinks.
- Stay active: Aim for 150 minutes of moderate exercise per week. Exercise releases endorphins that improve mood.
- Prioritise sleep: Keep a routine and aim for 7–9 hours each night.
- Stay connected: Social contact with friends and family supports mental wellbeing.
- Mind–body techniques: Mindfulness, meditation, or yoga can reduce stress.
- Limit alcohol and avoid recreational drugs: These can worsen mood and interfere with medicines.
Accessing Mental Health Services
If at any point you feel that you are struggling, please seek out professional help as soon as possible at the following services:
- NHS GP - first point of contact if not an emergency
- NHS 111 service
- Local mental health services and therapies (if applicable to you). The following link can help you find this:
https://www.nhs.uk/nhs-services/mental-health-services/how-to-find-local-mental-health-services/
Red Flag Symptoms to Watch Out For
Seek urgent medical advice if you experience:
- Thoughts of self-harm or suicide
- Severe or sudden worsening of depression or anxiety
- Hallucinations or new confusion
- Inability to eat or drink for several days due to nausea
- Rapid weight loss with extreme fatigue and low mood
If symptoms are severe, call 999 or attend A&E.
Summary
GLP-1 medicines like Wegovy and Mounjaro act on the brain as well as the gut, and may influence chemicals such as dopamine and serotonin. While some studies raise concerns, large clinical trials and the EMA have not shown a proven link to depression or suicidality.
If you have a mental health condition, you can usually use GLP-1 medicines safely — provided you are monitored by your GP or mental health team, watch for red-flag symptoms, and support your treatment with healthy lifestyle choices.
References
- Holst JJ, Knop FK, Vilsbøll T, Krarup T, Madsbad S. Loss of incretin effect is a specific, important, and early characteristic of type 2 diabetes. Diabetes Care. 2011;34(Suppl 2):S251–7.
- Anderberg RH, Richard JE, Eerola K, et al. Glucagon-like peptide 1 and its analogs act in the brain to regulate mood and reward. Front Neurosci. 2016;10:30.
- Drucker DJ. GLP-1 physiology informs the pharmacotherapy of obesity. Mol Metab. 2022;57:101351.
- Pottegård A, Kristensen KB, Johnsen SP, et al. Suicidality and GLP-1 receptor agonists: a pharmacovigilance study. Diabetes Obes Metab. 2023;25(8):2151–9.
- Al-Hussainy N, et al. Psychiatric adverse events with GLP-1 receptor agonists: A real-world safety signal analysis. Front Pharmacol. 2023;14:1165489.
- Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. N Engl J Med. 2021;384(11):989–1002.
- European Medicines Agency. PRAC meeting highlights, April 2024. Available from: https://www.ema.europa.eu