Prostate cancer drugs taken by thousands of men can cause depression, say scientists.
Androgens are male hormones that play a key role in stimulating prostate cell growth.
And as a result therapies that suppress androgen activity are a common treatment for prostate cancer.
Now a study published in the Journal of Clinical Oncology has found a link between depression and patients being treated for localised prostate cancer (PCa) by androgen deprivation therapy (ADT).
It follows research showing the treatment can double the risk of patients developing Alzheimer’s disease.
Dr Paul Nguyen, of Brigham and Women’s Hospital in Boston, said: “We know patients on hormone therapy often experience decreased sexual function, weight gain and have less energy – many factors that could lead to depression.
“After taking a deeper look we discovered a significant association between men being treated with ADT for PCa and depression.
“This is a completely under-recognised phenomenon. Around 50,000 men are treated with this therapy each year.
“It’s important not only for patients to know the potential side effects of the drugs they’re taking but also for the physicians to be aware of this risk in order to recognise signs of depression in these patients and refer them for appropriate care.
“Patients and physicians must weigh the risks and benefits of ADT and this additional risk of depression may make some men even more hesitant to use this treatment – especially in clinical scenarios where the benefits are less clear such as intermediate-risk disease.”
Prostate cancer is the second most common cause of cancer death for men in the UK with over 41,000 men diagnosed each year. Most of these are treated with hormone therapy.
In the study researchers reviewed data on 78,552 prostate cancer patients over the age of 65 investigating the association between ADT and a diagnosis of depression or psychiatric treatment.
The patients who received ADT had a 23 percent increased risk of depression and a 29 percent increased risk of hospital psychiatric treatment.
This also increased with the duration of the therapy from 12 percent with less than six months to 26 percent from 7 to 11 months of treatment to 37 percent with patients being treated for 12 months or longer.
Previous research has suggested low levels of testosterone may weaken the ageing brain’s resistance to Alzheimer’s.
It has been known for some time drastically reducing androgen activity can have adverse side-effects.
Past studies have shown that testosterone has a ‘general protective effect’ on brain cells.
Research in mice and humans have suggested lower testosterone levels could also allow greater production of the Alzheimer’s protein amyloid beta.