© Getty Images

Tom DeLonge - The Blink-182 guitarist recently offered his support to a fan struggling with mental health issues. "YOU are why I do this [...] we can be in charge of our own thoughts, the idea of who we are, what we can become."

© Getty Images

Ariana Grande - The singer has previously revealed that she was diagnosed with PTSD following the Manchester Arena attack. Recently, on Instagram, she said that Jim Carrey's words had actually helped her.

© Getty Images

Jim Carrey - The actor is known for being outspoken about his depression, and he took to Twitter to return the admiration for his unexpected longtime fan, praising Grande for her own openness.

© Getty Images

Bebe Rexha - Bebe Rexha posted on Twitter on April 15, 2019, revealing that she suffers from bipolar disorder. She says that she's "not ashamed" of her disorder, and that she's not looking for pity, but for acceptance.

© Getty Images

Jennifer Lawrence - The actress described her experience with anxiety associated with trying to cope with life as a public figure in an interview with The New York Times.

© Getty Images

Demi Lovato - The singer has become a sort of poster child for mental health awareness for her efforts to remove stigma by openly discussing her bipolar diagnosis and addiction. She's also behind the campaign 'Be Vocal: Speak Up For Mental Health.'

© Getty Images

Ryan Reynolds - In an interview with Variety, the actor revealed how he grew up struggling with anxiety, which has carried over into his adult and professional life. He credits his wife, Blake Lively, for helping him cope with it.

© Getty Images

Catherine Zeta-Jones - Catherine Zeta-Jones revealed she has been diagnosed as bipolar, which means she suffers from extreme highs and lows.

© Shutterstock 

Emma Thompson - Emma Thompson has battled severe depression for most of her life.

© Shutterstock 

Kesha - The singer has candidly opened up her struggles with an eating disorder, which she sought help for in 2014. In a piece she wrote for Time, she urged readers to take a break from attempting to please everyone and be kind to themselves.

© Getty Images

Kendrick Lamar - The rapper talked candidly in a 2015 interview about his struggles with depression and suicidal thoughts, which feature prominently in his album 'To Pimp a Butterfly.'

© Getty Images

Cara Delevingne - Cara Delevingne has also opened up about her struggles with mental illness, saying that she was hit with a huge wave of depression, self-hatred, and anxiety that resulted in self-harm.

© Shutterstock 

Adele - Adele has opened up about slipping in and out of depression and dealing with anxiety.

© Shutterstock 

Emma Stone - The actress has opened up about her history with panic attack disorder and how therapy and acting help her cope with the condition.

© Getty Images

Michelle Williams - The former Destiny's Child star sought help for mental health issues. The singer took to Instagram to write a touching message about her experience and to urge others "to recognize when it's time to seek help."

© Getty Images

Ellie Goulding - Ellie Goulding opened up about having cognitive behavioral therapy to battle negative thoughts around the time her career was taking off.

© Shutterstock 

Zayn Malik - Zayn Malik has said he sometimes suffers from depression and extreme anxiety, which has forced him to cancel shows in major cities.

© Shutterstock 

J.K. Rowling - J.K. Rowling has said that she suffered from severe depression in her twenties.

© Shutterstock 

Brooke Shields - The actress has been vocal about developing postpartum depression after the birth of her first child, which pushed her to contemplate suicide, and her subsequent decision to take medication.

© Getty Images

Princess Diana - Princess Diana spoke candidly about her experience with postpartum depression and self-harm in her 1995 interview with Martin Bashir.

© Shutterstock 

Olly Alexander - Olly Alexander, lead singer of Years & Years, struggled with self-harm, bulimia, and depression.

© Shutterstock 

Gabourey Sidibe - In her memoir 'This Is Just My Face: Try Not to Stare,' the actress discusses her struggles with depression and bulimia in college, as well as her decision to seek professional help.

© Getty Images

Will Young - Will Young has recently spoken about his struggles with depression, saying that he even considered breaking his legs to get out of performing in 'Strictly Come Dancing.'

© Getty Images

Stacey Solomon - Stacey Solomon found it hard to bond with her baby due to her postnatal depression.

© Shutterstock 

Melanie Chisholm - Mel C revealed that she suffered from mental health issues while she was in the Spice Girls.

© Shutterstock 

James Arthur - James Arthur said he suffered from depression and contemplated suicide after being dropped from Simon Cowell's record label.

© Shutterstock 

Jade Thirlwall -

Jade has spoken out about her battle with depression and anorexia.

So how do you know if you or someone you love has depression? Read on to find out.

© Shutterstock 

What to look for? - Depression varies from person to person, but there are some common signs and symptoms to look out for.

© Shutterstock 

Feelings of helplessness - Saying things like "It would be better if I weren't here" or "I want out" are an indication of suicidal tendencies in a person.

© Shutterstock 

Lack of interest - The lack of interest in things you once found pleasurable could mean your brain is not producing enough serotonin.

© Shutterstock 

Mood swings - A sudden switch from sadness to extreme calm, or appearing to be happy can be a warning sign.

© Shutterstock 

Change in weight - Significant weight loss or weight gain are commonly associated with depression. 

© Shutterstock 

Change in appetite - This can be due to emotional overeating or loss of appetite, which can both indicators of mental health struggles.

© Shutterstock

Anxiety - Anxiety and depression are often linked. People with depression can often experience symptoms such as nervousness and agitation, and have issues concentrating.

© Shutterstock 

Insomnia - Insomnia is also a common affliction for people who suffer from depression.

© Shutterstock 

Fatigue - Fatigue or the slowing down of physical movements, speech, and thought processes are all closely linked to depression and other mental disorders.

© Shutterstock 

Self-loathing - Strong feelings of worthlessness, guilt, and self-loathing are causes for concern.

© Shutterstock 

Irritability - Feeling agitated, restless, or even violent could mean you or a loved one is suffering from extreme mood swings or depression.

© Shutterstock 

Constant headaches - Headaches that are related to depression are usually dull and generalized.

© Shutterstock 

Unexplained aches and pains - An increase in physical complaints such as headaches, back pain, aching muscles, and stomach pain could be related to mental health.

© Shutterstock 

Recklessness -

Escapist behaviour such as substance abuse, compulsive gambling, reckless driving, or dangerous sports could mean the person in question is suffering from depression.

See also: Celebrities who have battled with depression.

© Getty Images