Raising questions about the effectiveness of self-help books, researchers have found that consumers of self-help books are more sensitive to stress and show higher depressive symptoms.

“The sale of self-help books generated over $10 billion in profits in 2009 in the US, which is a good reason to find out if they have a real impact on readers,” said one of the researchers Sonia Lupien from the University of Montreal in Canada.

“Our results show that while consumers of certain types of self-help books secrete higher levels of cortisol (a stress hormone) when confronted with stressful situations, consumers of another type of self-help books show higher depressive symptomatology compared to non-consumers,” said first author of the study Catherine Raymond from the University of Montreal.

The researchers recruited 30 participants, half of whom were consumers of self-help books.

The team measured several elements of the participants, including stress reactivity (salivary cortisol levels), openness, self-discipline, extraversion, compassion, emotional stability, self -esteem and depressive symptoms.

The group of self-help book consumers was itself divided into two types of readers: those who preferred problem-focused books and those who preferred growth-oriented books.

Examples of growth oriented self-help books include You’re Stronger Than You Think or How to Stop Worrying and Start Living. Titles of problem-focused books include Why Is It Always About You? or How Can I Forgive You?: The Courage to Forgive, the Freedom Not To.

The results showed that consumers of problem-focused self-help books presented greater depressive symptoms and growth oriented self-help books consumers presented increased stress reactivity compared to non-consumers.

“It seems that these books do not produce the desired effects,” Lupien noted.

The findings were published in the journal Neural Plasticity.