Shawn Johnston will always remember the taunting.

At 13, Johnston was slightly overweight and had yet to hit puberty. Worst of all, his emotionally distant father would encourage Shawn's two younger brothers to mock his appearance.

"They'd all have a big laugh. It was for 'fun,' but it actually wasn't fun for me," said Johnston, 40, who lives in Vancouver and runs a Web strategy agency.

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"They would go on for hours where they would come up with fat jokes or late-bloomer jokes."

The jeering went on for nearly a year, until his mother – they have since divorced – finally put a stop to it.

Yet, that was hardly the limit of his father's abuse. "He was always unkind. There were lots of times when he said he wasn't proud of me or that I was disappointing," Johnston said. "I still struggle with that sense of unworthiness."

Child protection agencies across Canada now recognize emotional abuse – screaming, name calling, bullying and making humiliating comments – alongside other forms of parental abuse, including physical and sexual abuse. It can inflict lasting damage on a child's mood, mental health and behaviour. And when emotionally abused children grow up, many see no choice but to end their relationships with their parents.

Even name calling can warrant an investigation of emotional abuse, said Pat Sisson, a child welfare supervisor at the Children's Aid Society of Toronto.

The organization was once contacted anonymously by a person who heard his neighbour yell at his adopted son that the boy was the worst $40,000 they ever spent."That was enough for us to go out and talk to them," Sisson said. "It's hard to prove sometimes, but we will go out and begin to talk to parents about how words matter."

Taunting and group bullying like that experienced by Johnston clearly fall into the category, according to Gary Walters, a psychology professor at the University of Toronto who has studied abusive parents.

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He said that emotional abuse can result in anxiety, depression, and, often, risk-taking behaviours, but even the most abusive parent often refuses to acknowledge any wrongdoing. "They don't see this as bad," Walters said. "They really think that this is the way to go."

Robyn Bambrick, a teacher in Alberta, was raised by a mother she said is a narcissist who not only withheld affection but regularly belittled her. "She would taunt me in the morning when I was trying to go to school," Bambrick said about a period in high school when the two lived alone following her parents' divorce.

Now trying to be a "healthy, engaged mom myself," Bambrick has kept her relationship with her mother to a bare minimum for several years. She has seen her at funerals and a nephew's baseball game, but that's it.

"My husband and I have decided she's not really a safe person. She's not trustworthy," she said. "You love her from a distance and you don't let them in your inner circle."

(Both Bambrick and Johnston declined to put The Globe in touch with their parents, saying it would cause too many problems within their extended families.)

"The parent who doesn't let the child be an individual and form their own opinions, who denigrate them, [is] being a toxic parent as much as the parent who hits and leaves bruises on the outside," said American author and therapist Susan Forward.

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She considers both emotionally and physically abusive parents "toxic," as she outlines in her 2002 book, Toxic Parents: Overcoming Their Hurtful Legacy and Reclaiming Your Life. Toxic parents are those who "assault your dignity, your self-respect, your confidence, your appearance, your intelligence. There's so much self-loathing that comes out of that, and a sense of despair."

Before patients entirely cut ties with toxic parents, Forward counsels them to first confront their parents and let them know how their negative behaviour affected them in childhood and beyond. If the parent shows some remorse or signs of being willing to build a healthier dynamic, it might be possible to repair the relationship. If not, it may be time to consider a difficult but necessary choice.

"Ask yourself what you are getting from a relationship with your parents, and if the answer is nothing, or pain, then you might want to consider a cut-off," Forward said.

That drastic decision is rarely easy, but is often the healthiest choice to make, Forward said. "I have taken hundreds of people through a cut-off, and with only one exception, they have not regretted it and it has empowered them and made their lives better."

Johnston said he has never been able to make his father see the hurt he caused. Five years ago, he asked his dad not to bring a parade of girlfriends to his house, and his father broke ties with him. He hasn't had any contact with him since.

"From my dad's victim perspective, he did the best he could and he sacrificed a lot and he really doesn't understand why we wouldn't thank him for everything he did," he said.

He and his mother, who is now 14 years sober, have a "workable" relationship now that she has dealt with the alcohol problem she had when he was growing up, Johnston said. "Particularly going through the 12-step process, there was a lot of reconciliation. There was a lot of apologies. It was a healing process," he said.

The same can be said for conversations he has had with his brothers in adulthood, which showed him that both of them dealt with a fair bit of toxicity as well.

Although the relationship with his father may be over, the effects persist. "There's some anxiety that I deal with from the trauma. I have some OCD tendencies, mostly obsessive thought patterns usually focused around doubt and self-worth," Johnston said.

He is trying to work through his childhood with a therapist, and doing his best not to repeat any of his own father's behaviour with his two children, a 13-year-old daughter and 11-year-old son.

"My son was being overly dramatic [recently] and manufactured a stutter to pretend that he was extra scared. I kind of mimicked him back. It wasn't the right thing to do. It just sort of happened," Johnston said. "An hour later, when he was calmer, I sat down and said, 'It wasn't right and I shouldn't have done that. I'm really sorry. Can you forgive me?' Which is nothing my father ever did."

Walters, the U of T professor, said that parents must recognize just how much impact even mild forms of shaming can have on a child. No, the occasional sarcastic comment or snide remark toward a child doesn't qualify as abuse, but "they can internalize it, and it will affect them," he said.

Children of toxic parents often bear lifelong scars, and Johnston said he will never be free of the pain, nor of the hole it left in him.

"I always knew my dad loved me after a fashion. I always wanted him to be proud of me," Johnston said. "Love is easy enough to give in easy moments. In terms of knowing I was worthy, it's the pride that you hunger for most."