"For anybody who has an addiction to something, the experience of engaging in the addictive behaviour is so intense that thoughts and stress and distress disappear. So in that moment there is only the compulsion and following through on what that compulsion might be," Mr MacDonald said.
He said there was little "good data" around on the issue but had seen it impact some unlikely people.
"It's not the hunchback with the trench coat and the warty nose," he said. "This is actually something... normal people get caught up in; just like the stereotype of the drug user is no longer true."
Another man embodying that theory appeared in North Shore District Court this month facing two charges of doing an indecent act in public.
The business owner and father in his 40s is alleged to have been running in front of two female joggers in August.
Court documents say he stopped outside a childcare centre before pulling his shorts down to his ankles and exposing himself to the women - one of whom was an off-duty policewoman - as they ran past.
Less than three months later a woman complained to police that the same man pulled over in his car in broad daylight and walked towards her with his genitals exposed.
The defendant's lawyer said he completely denied both charges and he had suffered many sleepless nights as a result of the embarrassing allegations.
Mr MacDonald said that with easier access to pornography, society would likely see an increase in "dysfunctional sexual behaviour".
But the anecdotal rise in people coming before the court on such matters could also be the result of people feeling more confident or empowered to report inappropriate behaviour to police, he said.
An ex-advertising professional from Auckland had his world collapse around him late last year when police knocked on his door.
The man in his 30s, who agreed to tell his story on condition of anonymity, had a well-paid job, a loving partner and a spotless criminal history.
But in July, work stress drove him to "a horrible horrible place".
He would drive out to a remote west Auckland beach where he got undressed and masturbated.
Three times in a month he was seen by people walking their dogs, who noted down his car registration as he made a speedy escape.
He admitted the offending at Waitakere District Court and was sentenced to come up if called upon - essentially a six-month good-behaviour bond.
"Historically I've had an inability to communicate very well. In my work life there was a huge amount of pressure on me," he said.
"After a period of time I was in the position where I was super stressed out... the only way I could deal with that stress was to get away from the situation. So I just left were I was and did what I did."
But he said the lewd beachside displays did not help his mental state, only added to his stress.
Now undergoing therapy, he said it was difficult to reconcile who he was back then.
"In a funny way I'm grateful those people did complain. If they hadn't, the chances are I wouldn't be in the healing process I am now... who knows, it could've got worse, and then we'd be having a much different conversation," he said.
He lost his job when charges were laid and his partner struggled to come to terms with what he had done.
But after months of counselling he was rebuilding his relationship and had new employment in a less pressure-filled role.
"I'm so determined to make sure this never happens again."
Recent cases:
May 2014 - An accountant is sentenced to 230 hours community work and 18 months intensive supervision after admitting trawling cinemas, committing indecent acts on young girls
June 2014 - A high-profile professional, whose case is covered by heavy suppression orders, appears in court accused of committing indecent acts in front of central Auckland joggers
Dec 2014 - A former advertising professional is sentenced to a six-month good-behaviour bond after being court masturbating three times at remote west Auckland beaches
Jan 2015 - An ex-social worker is ordered to undertake intensive supervision after admitting to using a mirror to look between girls' legs in a library
Feb 2015 - A company director will appear in Waitakere District Court charged with performing indecent acts in a west Auckland mall
March 2015 - A North Shore businessman and father will be back in court facing two charges alleging he exposed himself in public. One of the complainants is an off-duty policewoman.
