Some people have called the Samaritans helpline 'just to have another voice', its regional director says.
Rory Fitzgerald told Pat Kenny the organisation is preparing for a busy Christmas period.
He said people should try to focus on what is good in their lives.
"There's a lot of people living on their own around the country, and sometimes people ring us just to have another voice on the day.
"Coming up to Christmas it's very, very important that people use our service - or talk to somebody.
"We took 40,000 calls last December, so that'll give you the level of people that want to talk".
He said the coronavirus lockdowns have "magnified" life issues for some people.
"There's people now who are struggling who never struggled: all our lives in the last nine months have been turned upside down".
He added that Christmas can remind some people of loss.
"Some people hate Christmas, they just want to get past that day because it reminds them of people they've lost.
"They may be on their own: there's a lot of people out there sitting, having their own Christmas dinner on their own.
"It's a very, very difficult time.
"We have this thing that everybody should be happy and delighted - but it's not really like that in reality".
He said people should focus on the positive aspects of their lives.
"One thing we would say to people is there's good stuff in your life, so try to reflect on that - because if we start reflecting on the negative, it gets worse".
"There's lots of good stuff there too, and that's what we should try and reflect on".
It comes as a new study found that young girls under 15-year-old were four times more likely to self-harm than their male peers.
The National Registry of Self-Harm shows girls aged 15-19 were those most likely to present at hospital with self-harm injuries last year.
For boys, the peak rate was in 20-24 year olds, at 485 per 100,000.
These rates imply that one in every 138 women in the 15-19 age group, and one in every 206 men in the 20-24 age group, presented to a hospital in 2019 as a consequence of self-harm.
There were 12,465 presentations to hospitals due to self-harm last year, involving 9,705 individuals.
The age-standardised rate of individuals presenting was 206 per 100,000 - 2% lower than in 2018, and 8% lower than the peak rate of 223 per 100,000 recorded in 2010.
Last year the national male rate of self-harm was 187 per 100,000, 3% lower than 2018.
The female rate was 226 per 100,000, a drop of just 1% from the year previously.
Mr Fitzgerald said the best thing is to talk about it.
"There's a lot of stigma around it, there's a lot of guilt, shame and isolation and the important thing - if parents are worried about their children - is not to judge them.
"Self-harm is a sign that one is struggling to cope and finding it difficult to express feelings of overwhelming emotional distress.
"Our mantra for everybody... is to talk about it".
He said such instances are symptomatic of something else going on.
"It's down to the parents to support them in that - we would say get them to talk and open up about what's really going on, because it's obviously a symptom of something else happening in their lives".
Anyone affected by issues raised in this article can contact The Samaritans by calling 116-123