Does Prozac cause mood swings? (+3 evidences)

In this article, we will discuss if Prozac tends to alter your mood and cause mood swings. A mood swing is an abrupt or dramatic shift in a person’s emotional state. Mood swings in men and women can have a variety of causes, such as physical or mental health issues, and the use of certain antidepressants. 

Does Prozac cause mood swings?

Yes, Prozac can cause mood swings. During the initial stages of Prozac administration, you might experience mood swings. These mood swings can be mild with no effect on your daily life, or they might be intense and interfere with your daily work. Once the body is adapted to the drug, these symptoms might go away. Clinical data also suggest that Prozac can be used to treat mood swings in certain disease conditions.

When starting the treatment, the patient should keep an eye out for new or worsening suicidal or depressive thoughts. This includes abrupt mood change, behaviour, or thought shift. These changes can occur at any moment but are more likely to happen at the start of treatment or following a dose modification.

Patients with bipolar disorder who use Prozac may experience manic episodes. Change in feelings or behaviour such as feeling worried, nervous, irritable, hostile, aggressive, agitated, and hyperactive episodes should be monitored.

How is Prozac linked with mood swings?

The destabilizing effect of Prozac on mood in Bipolar disorder (BD) has been attributed to the alteration in the Plns cycle. Prozac increases the integration of inositol generated by PIP2 (phosphotidylinositide, 4-5 biphosphate) hydrolysis into Plns resynthesis, which explains Prozac’s capacity to cancel off the effect of other stimulants used to stabilise mood swings (1). 

It is also possible that Prozac’s effects on Plns turnover contribute to its antidepressant effect in unipolar depression, but more cruicially, to its mood destabilising effects in bipolar patients when taken without the balance of a mood stabilizer (1). 

It has been reported that patients suffering from ‘subaffective syndrome’ (subsyndromal form of major mood disorder) respond well to Prozac treatment. Prozac has been found useful in patients who do not exhibit premorbid traits but whose depression is characterised by mood swings, irritability, and rumination (2). 

What does the research suggest?

Prozac is prescribed to treat depression, panic attacks, bulimia, and premenstrual syndrome. Clinical data suggests that Prozac primarily aids in the improvement of mood swings, hunger, sleep, and energy levels, as well as the elimination of undesirable thoughts, fear or worry. It is a beneficial treatment to stay calm and relaxed (3).

In a three-blind clinical trial, it was established that Prozac decreased the symptoms associated with premenstrual syndrome including mood swings, depression, and abdominal bloating. It was also able to relieve breast and stomach discomfort (4).

In another case, a pregnant woman who presented with severe cases of nausea and vomiting during pregnancy was treated with Prozac due to her depression. She also admitted to being afraid of premature birth, and postpartum depression. After receiving Prozac for six days, she was able to accept an intake of antiemetic drugs. She reported feeling happier and experienced improvement in her mood swings and sleeping patterns. She added that she had given up on ending her pregnancy (5). 

Prozac can also be used to improve mood swing associated with premenstrual disorders in which the patient might experience mental, behavioural, and physical symptoms that appears the day before and disappear immediately after menstruation (6). 

What other factors might influence mood while on Prozac?

Various factors can cause mood swings while you are taking Prozac. 

  • Diet: A person may have mood swings due to blood sugar fluctuation and malnourishment if they are consuming an inadequate diet. Mood swings have also been linked to digestive problems like inflammatory bowel disease, and celiac disease that impair the body’s capacity to absorb nutrition. 
  • Prescription drugs: A person’s mood may change by taking or quitting a prescribed medicine. Although mood swings are a common side effect of antidepressants and mood stabilisers, mood swings can also be brought on by prescription drugs for other purposes (7).
  • Sleep: The quantity of sleep that an individual receives can also have a significant impact on their mood. Intense mood swings and other psychiatric symptoms might be experienced by someone who lacks sleep, especially if the condition is chronic. 
  • Substance abuse: Extreme mood swings may also be more common in people with substance abuse disorder, particularly when they are unable to get or use a substance. Mood swings can also occur during the withdrawal period.

What is the prognosis of mood disorder?

The prognosis for mood disorders is dependent upon multiple factors such as:

  • The nature of ailment and how bad it,
  • How quickly it is identified, and
  • If it receives the right care.

A poor prognosis is increasingly linked to recurrent episodes of mood disorders that can lead to underscoring the significance of prompt and efficient treatment. 

How to manage mood swings when taking Prozac?

Mood swings can be difficult, particularly if they affect your relationships, job or school, and daily activities. Frequent and severe mood swings should be discussed with your doctor because treating them properly depends on determining the underlying medical reason. 

The first step is figuring out what aspects of your life and surroundings, like stress, and restless nights, are contributing to or preceding your mood swings. Depending on the reason, you should modify your lifestyle and adopt more positive changes in your life.

Prozac is known to cause anxiety in the initial phases of the therapy. If Prozac is causing exacerbating mood swings, medications known as mood stabilisers, psychotherapy, counselling, and cognitive behavioural therapy (CBT) may be beneficial. 

When to consult the doctor?

If the intensity of mood swings affects the quality of life then it is better to consult the doctor. The doctor will inquire about past medical history, any drugs co-administered with Prozac, and any diagnosis of mood disorders in the family. Although there is currently no known way to prevent mood disorders, medications may be able to decrease many of the associated problems.

The doctor might advise the patient to switch to a different antidepressant, increase the dosage of Prozac, or combine it with other mood stabilizers as part of your ongoing treatment. 


In this article, we have discussed the impact of Prozac on mood swings. We have also discussed some non-pharmacological of managing mood swings while on Prozac.

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Saiardi A, Mudge AW. Lithium and fluoxetine regulate the rate of phosphoinositide synthesis in neurons: a new view of their mechanisms of action in bipolar disorder. Translational psychiatry. 2018 Aug 31;8(1):175.


Bell DS, Shipman WM, Cleves MA, Siegelman J. Which drug for which patient? Is there a fluoxetine responding versus a bupropion responding personality profile?. Clinical Practice and Epidemiology in Mental Health: CP & EMH. 2013;9:142.


Nemat-Shahi M, Asadi A, Nemat-Shahi M, Soroosh D, Mozari S, Bahrami-Taghanaki H, Mehrpour M. Comparison of saffron versus fluoxetine in treatment of women with premenstrual syndrome: A randomized clinical trial study. Indian Journal of Forensic Medicine & Toxicology. 2020 Apr 1;14(2).


Chin LN, Nambiar S. Management of premenstrual syndrome. Obstetrics, Gynaecology & Reproductive Medicine. 2017 Jan 1;27(1):1-6.


Cartwright C, Gibson K, Read J, Cowan O, Dehar T. Long-term antidepressant use: Patient perspectives of benefits and adverse effects. Patient Prefer Adherence. 2016; 10: 1401–7.

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