With Melbourne Bariatric Surgeon Dr Jason Winnett and Winnett Specialist Group Psychologist Kylie Murphy

Obesity and depression are common comorbidities with a clear bidirectional relationship, says Melbourne Bariatric Surgeon Dr Jason Winnett. 

If a patient has one condition, they may well have the other. 

According to a JAMA Psychiatry study, individuals living with obesity have a 55% increased risk of depression compared with those without obesity in a meta-analysis of 58,745 people. 

The same study found that persons living with depression had a 58% increased risk of becoming obese.

A 2023 review of genetic studies in the Journal of Psychiatric Research supports this link, concluding that obesity can directly raise depression risk.

How obesity can lead to depression (and vice versa)

‘The relationship between obesity and depression is very complex,’ says Dr Jason Winnett. ‘Firstly, obesity increases inflammatory markers in the body, which are strongly linked to depression.

‘Secondly, obesity impacts insulin resistance, leptin signalling and cortisol regulation, which also interact with brain circuits involved in mood regulation. 

‘Thirdly, people living with obesity also frequently experience reduced quality of life, body image distress and social exclusion.’  

The risk runs the other way, too.

Depression often reduces activity, can dramatically disrupt sleep and the motivation to exercise and is frequently linked to emotional eating, as patients may use ‘comfort foods’ to self-soothe.

Can antidepressants cause weight gain?

According to a large study of nearly 300,000 people reported in the British Medical Journal, about 11% of people taking antidepressants gained 5% or more of their body weight each year, compared with 8% of those not on antidepressants.

One popular antipsychotic resulted in a 6.1kg gain for patients after four years, according to the Journal of Psychopharmacology.

Dr Winnett says, ‘The same reason antipsychotics are beneficial for mental health conditions is why they can affect weight. This is because they act on brain chemical messengers (neurotransmitters) such as dopamine, serotonin and histamine, which in turn affect the hormones that control appetite.’

Weight-loss medications, diabetes medications, and their impact on mental health

Weight-management medications that have become popular in recent years also seem to have a complex relationship with mood. 

In 2023, reports of suicidal thoughts in some users raised concerns, and a 2024 global records study added to these worries, according to Scientific Reports. 

It found that people living with obesity taking weight-management medications had a higher risk of depression, anxiety and suicidal behaviour. 

A 2026 review in BMC Psychiatry pooling 19 studies found use of weight-loss medications was linked to a 49% higher risk of depression-related outcomes, although the studies varied widely and the authors cautioned that their results don’t show these medications cause depression.

More encouragingly, however, another 2026 Lancet Psychiatry study of more than 95,490 people with existing depression or anxiety who were prescribed diabetes medications found that weight-loss medications were associated with a lower risk of worsening mental health.

‘The research on weight-loss medications is fast evolving, and the findings don’t always move in the same direction,’ says Dr Winnett. ‘Everyone responds differently, so we ask patients to tell us about any history of depression before they start, and to let us know straight away if their mood changes.’

Incidence of mental health conditions in general population v bariatric patients

	General population	Bariatric patients
Living with mood disorder	10%	23%
Living with depression	8%	19%
Living with binge-eating disorder	1-5%	17%

 

Source: Mental Health Conditions Among Patients Seeking and Undergoing Bariatric Surgery (results), JAMA 2016

Is bariatric surgery safe for patients with mental health concerns?

In decades past, patients with bipolar disorder, depression or schizophrenia were once routinely advised against bariatric surgery. However, this view is shifting.

A 2025 meta-analysis of more than 732,000 patients found that compared to nonsurgical interventions, surgery may improve depression, anxiety, non-normative eating, and attention, but may slightly increase suicides and substance-use disorders. 

Another large Western Australian study found in JAMA Psychiatry that there were more presentations to the ER and psychiatric episodes after bariatric surgery, especially if there were post-surgical complications or if there was a history of deliberate self-harm and psychiatric substance use disorder before surgery. 

‘Certainly, these patients need to be carefully monitored, and the evidence is mixed on whether surgery can exacerbate mental health conditions,’ says Dr Winnett.

However, the results suggested reductions in depression ranging from 8-74%  according to a meta-analysis of 65,363 patients in the Journal of the American Medical Association. The study found ‘moderate quality evidence supports an association between bariatric surgery and lower rates of depression post-operatively.’

Why psychological support is important before and after surgery

‘There is no silver bullet for long-term weight management,’ says Winnett Specialist Group psychologist Kylie Murphy. ‘Psychological support before and after bariatric surgery is vital for building sustainable habits, monitoring progress, and navigating inevitable challenges like weight plateaus.’ 

Rather than relying on willpower alone, Kylie helps patients understand the strong link between thoughts, emotions, and eating patterns. Her approach focuses on breaking automatic behavioural patterns, untangling emotional eating, and developing practical coping tools for life after surgery.

How to manage cravings

‘The key to managing cravings is to expect them and respond with a plan rather than reacting on impulse,’ explains Kylie. ‘Something as simple as changing your environment, pausing before meals, or doing a quick breathing exercise such as inhaling for four counts, holding for four, and exhaling for four, can effectively interrupt an automatic habit loop.

‘It’s equally important to practice self-compassion. A single slip doesn’t undo your progress. Harsh self-criticism only fuels low mood and emotional eating, so aim to speak to yourself with the same kindness you’d offer a close friend.’

Kylie also encourages patients to practice ‘urge surfing’ when an intense craving strikes:

‘Cravings behave like waves – they rise, peak, and usually subside within 10 to 15 minutes. Instead of fighting the urge or immediately giving in, notice it without judgment and let it pass. Pause and get curious: Is this genuine physical hunger, or am I bored, stressed, lonely, or tired? Naming the emotion or physical state strips away its power and keeps you from responding on autopilot.’

Caring for body and mind

Obesity and depression are closely linked, and each can make the other harder to manage.

Whether you’re considering surgery, starting medication or already on your weight-loss journey, your mental health matters as much as your physical health. 

At Winnett Specialist Group, our multidisciplinary team works together to support both. If you’ve noticed changes in your mood or would like to discuss your options, contact our team to book an appointment.

If you need support, contact Lifeline on 13 11 14 or Beyond Blue on 1300 22 4636. In an emergency, call 000.

References

1. Luppino FS, de Wit LM, Bouvy PF, et al. Overweight, obesity, and depression: a systematic review and meta-analysis of longitudinal studies. JAMA Psychiatry 2010;67(3):220–229.
2. Jokela M, Laakasuo M. Obesity as a causal risk factor for depression: systematic review and meta-analysis of Mendelian randomization studies and implications for population mental health. J Psychiatr Res. 2023.
3. Gafoor R, Booth HP, Gulliford MC. Antidepressant utilisation and incidence of weight gain during 10 years’ follow-up: population based cohort study. BMJ. 2018;361:k1951.
4. Bazo-Alvarez JC, Morris TP, Carpenter JR, Hayes JF, Petersen I. Effects of long-term antipsychotics treatment on body weight: a population-based cohort study. J Psychopharmacol. 2020;34(1):79–85.
5. Kornelius E, Huang JY, Lo SC, Huang CN, Yang YS. The risk of depression, anxiety, and suicidal behavior in patients with obesity on glucagon like peptide-1 receptor agonist therapy. Sci Rep. 2024;14:24433. doi:10.1038/s41598-024-75965-2.
6. Bi Z, et al. Glucagon-like peptide-1 receptor agonists and risk of depression: a systematic review and meta-analysis. BMC Psychiatry. 2026;26(1):379. doi:10.1186/s12888-026-08016-x.
7. Taipale H, Taylor M, Lähteenvuo M, Mittendorfer-Rutz E, Tanskanen A, Tiihonen J. Association between GLP-1 receptor agonist use and worsening mental illness in people with depression and anxiety in Sweden: a national cohort study. Lancet Psychiatry. 2026;13(4):327–335. doi:10.1016/S2215-0366(26)00014-3.
8. Dawes AJ, Maggard-Gibbons M, Maher AR, et al. Mental health conditions among patients seeking and undergoing bariatric surgery: a meta-analysis. JAMA. 2016;315(2):150–16
9. Psychiatric and cognitive functioning after metabolic and bariatric surgery: a systematic review and meta-analysis. Obes Rev. 2025. doi:10.1111/obr.13968.
10. Morgan DJR, Ho KM, Platell C. Incidence and determinants of mental health service use after bariatric surgery. JAMA Psychiatry. 2020;77(1):60–67.
11. Dawes AJ, et al. JAMA. 2016;315(2):150–163

Contact

P (03) 9417 1555

admin@winnettspecialistgroup.com.au

www.winnettspecialistgroup.com.au

Queens Terrace, 382 Victoria Parade, East Melbourne 3002

This page was reviewed by Dr Jason Winnett and psychologist Kylie Murphy, October 2026, AHPRA No: MED0001155541 

This article contains general information only, not medical advice. All procedures carry risks and results are individual. Consult your GP and a qualified surgeon or seek a second opinion before proceeding.