Facebook can help people recover from mental health problems but it needs to be used cautiously and strategically as it can also make symptoms worse, new research shows.

Dr Keelin Howard told the British Sociological Association's annual conference in Glasgow that users she interviewed found their paranoid, manic and depressive symptoms could worsen as well as improve.

Dr Howard, of Buckinghamshire New University, carried out research with 20 people aged 23-68 who had experienced conditions such as schizophrenia, bipolar disorder, depression and anxiety.

She told the conference that social media like Facebook could provide a source of social support and connection that were important for recovery. Some participants were positive about Facebook, saying it helped them recover by making them feel less alone, allowing them to express themselves and be part of an online community.

"It's like a mate sitting next to you," one told her. "It makes me feel like I'm not alone." Another said: "My friends are important to my mental health - sometimes I feel like I need to say what's on my mind and Facebook is one way of doing it."

Some participants had found that constructing a Facebook profile had played a part in rebuilding their identities after a mental health crisis, so facilitating their recovery.

Dr Howard said: "Many participants spoke of the way Facebook could enhance their mood through keeping up with their friends, and through receiving positive self-affirmation when other people liked or left comments on their posts." Facebook provided some with a less threatening means to communicate, gain and give peer support when 'face-to-face' communication was too intense.

But some participants also said it had worsened their condition, said Dr Howard. "All participants who experienced psychosis and dealt with paranoia had found Facebook particularly problematic when unwell. It often exacerbated or triggered feelings of paranoia, leading to an increase in delusions or psychotic thinking.

"Some became distressed that others' posts were aimed at them, whilst others became paranoid about how others would react to their posts. All participants with diagnoses of schizophrenia felt that Facebook was harmful when they were unwell."

One told her that he had believed he was under surveillance by mental health services via Facebook: "I was convinced that all the workers and nurses had been reading my Facebook page. I felt I was being watched and spied upon by people whose ultimate goal was to either kill me or drive me insane completely."

Dr Howard said: "Participants who identified as having bipolar disorder found that while manic they were far more active on Facebook and had posted things that they later regretted. They felt embarrassed by their comments and felt that it led to people misunderstanding them. One said 'I hung my head and deleted everything.'

"Several participants said that Facebook use led to anxiety, but one described it playing a part in severe anxiety as fellow students shared about their exam preparation, exacerbating extreme anxiety that then led to panic attacks."

Dr Howard said that users could mistake the tone of written comments on their page and feel rejected, or that their privacy had been invaded. Some had experienced online bullying.

"Some felt inundated by the large amount of information and emotions from so many people at once on Facebook. This could lead to over-activity, being affected by others' moods or finding that relative strangers knew personal information about them. The fact that posts were public and traceable led to feelings of vulnerability for some participants.

"Participants found that Facebook could be a vehicle both for challenging the stigma around mental health as well as a place where prevalent stigma around mental health conditions could make survivors feel more vulnerable or reticent."

However, over time many learned how to use Facebook wisely. One told her: "When you first sign up for Facebook there's no guidebook - you learn as you go along, and maybe there are things that make you paranoid and maybe that make you scared or trigger symptoms or delusions. So you have to work out how you're going to deal with it in this situation."

Dr Howard said: "All participants used Facebook strategically having learned over time and through experience to protect and enhance their mental health and well-being as well as of others. They had developed a variety of protective strategies, such as only 'friending' close and trusted friends and taking Facebook breaks.

"Several participants had learned to anticipate the effects of Facebook use on their mental health particularly during episodes of illness. One participant had put in place a plan - she had given her sister her Facebook password and put it in writing that she should change this password to prevent her using Facebook if she became manic."

Dr Howard said that the effects of Facebook on 'severe and enduring' mental health conditions had not been studied in depth before. "There is very little research that has explored the effects and issues of Facebook use for people who have experienced mental health issues, particularly for those who may be survivors of severe and enduring mental health conditions." She plans further research with a larger sample.