Do antidepressants make you fat? Here’s what you really need to know-

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Do antidepressants make you fat?  Here’s what you really need to know-

of Daniela Natali

a question you don’t always dare to ask your doctor. In reality, not all drugs cause weight gain and this can help us arrive at shared therapies

If it is not unlikely that someone will decide not to start an antidepressant treatment for fear of gaining weight, it is even more likely that he will stop it as he sees the scales shift. But is it really true that antidepressants make you gain weight? Or are there other factors that come into play? And then, from this point of view, are all drugs the same? Absolutely not – he replies Giancarlo cerveri director of the psychiatry unit of the Asst of Lodi – but let’s start by pointing out that almost all antidepressants are also active against anxiety that, among the many negative effects, it has some little known: increases intestinal peristalsis and basal metabolism because it increases muscle tension. In short, the internal “engine” is always accelerated and in fact there is a feeling of perennial fatigue and often, in the evening, the muscles are painful. Not infrequently, all this involves weight loss, but when the drugs begin to act, and the anxiety to subside, its side effects are also reduced and it is not uncommon that, if the introduction of food does not change and does not increase physical activity, weight gains, but this is not a direct effect of the drugs, but a symptom of improvement in the pathology.

The role of antihistamines

Beyond these effects, are there antidepressants that actually make you fat directly? All those with strong antihistamine activity, in particular la mirtazapina. I would like to make a distinction. If everyone knows that antihistamines used to fight allergies often cause weight gain, the ones we psychiatrists use are different. The first are hydrophilic, they dissolve in water, and this allows them to easily reach the mucous membranes of the nose where they have to act; the latter are lipophiles, dissolve in fat and then end up in the brain, which is the “fattest” organ in our body ”causing a sedative effect by binding to the histaminergic receptors present there. Another among the antidepressants often associated with weight gain la paroxetine, one of the many SSRIs, drugs that inhibit the “reuptake” of serotonin, the neurotransmitter “good mood”.


Which antidepressants have the least effect on weight? Fluoxetine, another SSRI, which has no effect on appetite-increasing receptors. And what about benzodiazepines, antipsychotics and mood stabilizers? Let’s clarify: benzodiazepines have no antidepressant activity and it is used only in cases of anxiety and insomnia, and with special attention in the elderly, who may have problems with falling at night due to reduced alertness upon awakening and induced motor and cognitive deficits. Antipsychotics are generally not used in depression except in rare conditions where delusional or hallucinatory symptoms are present, therefore very rare conditions. And to mood stabilizers, such as lithium or sodium valproate, it is used in the case of severe and resistant depressions in which other drugs have proved ineffective or for depressive conditions arising in people suffering from bipolar disorders. These are “delicate” drugs which should be handled only by specialists in psychiatry and with a strict control of blood values ​​to evaluate tolerance to the drug and avoid possible intoxication as the difference between therapeutic dose and limited toxic dose.

Second generation antipsychotics

Having clarified the limits of use of the aforementioned drugs, the question remains: do they make you fat? Benzodiazepines no, antipsychotics behave inhomogeneously, some little or nothing, some a lot and some a lot. Although several clinical studies point out that in some severe psychiatric disorders, weight gain is common due to poor nutrition and poor physical activity, it is certain that among the second generation antipsychoticsclozapine and olanzapine are those associated with the greatest weight gain; quietapina and risperidone at an intermediate increment, between lurasidone, aripiprazole and cariprazine at the smallest increase. Mood stabilizers can also cause weight gain, but generally to a lesser extent than antipsychotics.

Tricyclic molecules

And are the old tricyclics still used and what effect do they have on weight? Tricyclics at therapeutic dosages often have relevant undesirable effects, they are currently only prescribed if other drugs have been found to be ineffective, I’m certainly not the first choice. Their side effects are mainly: intestinal peristalsis block, dry mouth, dizziness when standing up and cardiological problems. They can also make you fat because they block histamine receptors.

Make previsions

Can one predict, more accurately, whether the antidepressants taken will make you fat? A study published in PlosOne in 2017 analyzed the link between diabetes and antidepressants and this, albeit indirectly, helps us to make more specific predictions. The link between these drugs and dietary diabetes has already been widely clarified, the goal of the study was to see if diabetes was caused by weight gain or if it was due to depression which in itself increases the risk of glycemic imbalances, or to the simple fact that patients on antidepressant therapy do more often than not check their glucose and therefore have more opportunities to notice that something is wrong. The study found that the ability to induce weight gain of these drugs can be predicted by theirs H-1 R affinity and that is the affinity with histamine receptors and therefore the “relationship” with histamine drugs. Fluoxetine, a serotonin reuptake inhibitor and bupropion (which acts on the reuptake of norepinephrine and to a lesser extent serotin and which is used for smoking detoxification, ed) were found to have the lowest affinity and therefore expose less to the risk of weight gain.

Shared choices

It is not easy to disentangle all these terms, on the other hand it is not up to the patient to prescribe a therapy, but can having information be used to talk about their doubts with the doctor? Of course, the choice of therapy must be shared and it is up to the doctor fmake accurate diagnoses and give “tailor-made” prescriptions, also taking into account age and lifestyles. And then the drug treatment should be accompanied by psychological therapy, which would not only enhance the effects but could reduce their duration over time.

How to avoid or limit any damage to the line

Although the drugs used today for the treatment of anxiety and depression do not have a direct effect on metabolism and weight, clinical experience explains Stefano Erzegovesi Head of the Center for Eating Disorders of the San Raffaele Hospital in Milan— indicates that especially women complain of a different and greater propensity for refined carbohydrates: from pizzas to biscuits. A possible explanation for this preference lies in thefacilitating effect of carbohydrates on the availability of tryptophan, the amino acid precursor of serotonin, in the brain. The solution lies in the favor unrefined carbohydrates: instead of biscuits and white bread, we eat a nice soup of cereals and legumes and, at the beginning of the meal, a plentiful plate of vegetables, rich in fiber that help to satiate. And less saturated fat. In addition to diet, physical activity counts, not only because it helps keep weight under control, but because it has a proven antidepressant effect. Also in the case of older people, who often take antidepressant therapies, ten thousand steps a day at a brisk pace make a real difference, both on the tendency to gain weight and on the improvement of mood. Better still, in addition to walking, a little anaerobic exercise: If you don’t feel comfortable with weights, it’s fine to take the stairs uphill or do some bending on your legs in the morning. There are also some antidepressants – concludes Erzegovesi – that actually increase appetite: they are those that act on histamine. Again the suggestions are the same: act on lifestyles, adopting healthier ones, which help maintain a healthy weight, a more stable mood and, last but not least, to combat age-related cognitive decline.

July 22, 2021 (change July 22, 2021 | 22:13)

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