“In the medical community, antipsychotics are well known to cause significant weight gain. Gains of 20 to 35 pounds or more over the course of a year or two are not unusual.”

– Andrea Alfano (2015B)

Both antidepressants and antipsychotics can cause significant weight gain in those who take them. This appears to be caused by disruption to the chemical signals that control for appetite, which causes people to eat more before feeling full. Yet there could also be other factors at work, such as a way in which the drugs affect metabolism or throw off the body’s endocrine system. A 2014 study of 22,610 people showed antidepressants generally cause a more modest weight gain compared to antipsychotics, although the outcome varies greatly from one drug to the next. (Alfano, 2015B)

A 2014 review of 8 studies found that as many as 55% of patients taking modern antipsychotics experience weight gain. (ibid) Another study found that most psychiatric medications bring on weight gain in kids as well. Researchers monitored 257 children ages 4 to 19 who were taking either olanzapine, quetiapine, risperidone or aripiprazole. After about 11 weeks, patients had gained an average of 10-19 pounds, depending on the drug. (Seppa, 2009)

Psychiatric drugs & type 2 diabetes

Weight gain and diabetes go hand in hand, so it’s not that surprising that psychiatric drugs have also been found to trigger the onset of type 2 diabetes. One study found that antipsychotic drugs such as risperidone (Risperdal) or olanzapine (Zyprexa) can elevate the risk of type-2 diabetes, with kids being even more at risk than adults. Researchers tracked kids who were being treated with antipsychotics and found they had a threefold increased risk of developing type 2 diabetes compared to children with similar characteristics who were taking other medications, such as antidepressants and anti-anxiety drugs. (Previous studies have found adults have roughly a twofold increased risk.) The study excluded kids who were prescribed these drugs for off-label conditions for which other medications were available, such as bipolar disorder or autism. (Wang,8-22-2013)

This risk translates into an estimated 16 additional cases of type 2 diabetes per 10,000 children who are taking an antipsychotic for one year. This increased risk showed up within the first year of treatment, so the long-term cumulative effects are likely even greater than what was captured in this study. Researchers noted that this increased risk could not be fully explained by the weight gain caused by the drugs, and suggested that the drugs themselves seem to increase insulin resistance. (ibid)

The ripple effects of antipsychotic-induced weight gain

These weight gains can lead to secondary effects and problems for patients, especially when they aren’t warned ahead of time. As one woman says, “Gaining weight made it even more difficult for me to want to leave my house because I felt self-conscious.” (It’s just one more example of how a patient’s mental health is linked to lifestyle variables, and why it’s better to treat these conditions through other means rather than cover them up with a drug.) The toll taken by type 2 diabetes is also severe, requiring constant monitoring and drastically lowering a person’s quality of life and life expectancy. So the overall toll taken by this side-effect can be quite severe.

Behavioral interventions can help offset this risk, but sadly, many doctors are turning to metformin, a diabetes drug, and topiramate, an anticonvulsant, to try and counteract the effects of antipsychotic induced weight gain, based on studies suggesting they might help. And so the never-ending cycle of medication on top of medication continues.