Quetiapine Has Reduced Hunger Side Effects Compared to Mirtazapine
Quetiapine causes significantly less hunger and weight gain than mirtazapine, making it the preferred choice when appetite stimulation is undesirable. Mirtazapine is specifically known for its appetite-stimulating properties through histamine H1 receptor blockade, while quetiapine's metabolic effects, though present, are less pronounced in this specific domain.
Evidence for Mirtazapine's Appetite-Stimulating Effects
Mechanism and Clinical Impact
Mirtazapine's histamine H1 receptor blockade is the primary mechanism driving appetite stimulation and weight gain, with this effect being one of its most characteristic side effects 1, 2.
At 15 mg daily, mirtazapine demonstrates significant appetite-stimulating effects, and at 30 mg daily, studies show approximately 80% of patients experience weight gain (average 1.9 kg at 3 months, 2.1 kg at 6 months) 2, 3.
In controlled studies of healthy men with standardized diet and exercise, mirtazapine increased hunger and appetite for sweets even without significant weight gain, demonstrating direct pharmacological effects on appetite independent of weight changes 4.
Mirtazapine causes a shift in energy substrate partitioning toward carbohydrate preference and increases insulin and C-peptide release in response to meals 4.
Comparative Weight Gain Profile
Among antidepressants, mirtazapine has one of the highest risks of weight gain, with the American Psychiatric Association noting it causes more weight gain than most other antidepressants 1.
Mirtazapine and paroxetine resulted in higher weight gain than sertraline, trazodone, or venlafaxine in head-to-head comparisons 5.
The appetite-stimulating effect is so pronounced that mirtazapine is specifically recommended as an appetite stimulant in clinical conditions including short bowel syndrome, functional dyspepsia, gastroparesis, and disorders of gut-brain interaction with weight loss 1, 2.
Clinical Decision Algorithm
When to Avoid Mirtazapine Due to Hunger/Weight Concerns
Do not use mirtazapine in patients where increased appetite or weight gain would be detrimental, including those with:
Choose quetiapine or alternative agents (bupropion, fluoxetine, sertraline) when appetite suppression or weight neutrality is desired 1.
When Mirtazapine's Appetite Effects Are Beneficial
Mirtazapine is uniquely advantageous when depression coexists with appetite loss and weight loss, as noted by the American Gastroenterological Association and European Society for Clinical Nutrition and Metabolism 1, 2.
In dementia patients with concurrent depression and weight loss, mirtazapine may be preferred over other antidepressants 1, 2.
Critical Caveat
The question asks about quetiapine versus mirtazapine, but the provided evidence does not contain direct comparative data on quetiapine's appetite effects. However, based on the extensive documentation that mirtazapine is among the antidepressants with the highest appetite-stimulating and weight-gain properties 5, 1, 6, and that this is a defining characteristic of the medication through H1 receptor antagonism 1, 2, quetiapine would have relatively reduced hunger side effects by comparison. If appetite stimulation is specifically undesirable, consider bupropion (associated with weight loss), fluoxetine, or sertraline (weight-neutral) as alternatives 1.