When a band start to focus on reissues and celebrating their archive, it's only natural to wonder if they are embracing the past in favour of the future.

Yet while Placebo's most recent announcement has been regarding making their previous albums available through online streaming, Brian Molko has no great desire to reflect on prior glories.

"I'm a little bit Bob Dylan about the whole thing: I don't really look back," he says, speaking ahead of a run of shows that will bring him to Edinburgh, Glasgow and Aberdeen this weekend.

"I try my best to look forward. Every now and again, by accident or for archival purposes, I'll look over Placebo's music, and sometimes I'm surprised by its quality, but there are moments of embarrassment for me, too. That's because I feel like I can do better; that's what drives me as an artist. I don't want to be crippled by what I see as naïve amateurism or mistakes."

This viewpoint isn't entirely surprising, as the band rarely play some of their biggest hits, such as Nancy Boy, live, while others are reinterpreted for modern gigs. Even this 20th-anniversary celebration is an elastic concept, given that Placebo was first formed in 1994 by Molko and bassist Stefan Olsdal (various drummers have joined them over the years), and that activities are planned all the way into next year, to mark two decades since their self-titled debut album was released.

While Britpop was in full-flow when Placebo first appeared, they were always standing outside its beery party, from their androgynous look and cynical lyrics to sonic influences that tapped into Goth and glam more than anything else. Chart success arrived swiftly, though, and Molko soon indulged heavily in rock music's temptations, particularly drug use. Now clean, he believes he's catching up on lost time.

"I'm still getting to know myself, I'm still getting to like myself," he says. "It's been a long journey for me to get to this point and a great deal of character development was lost or stunted because I completely embraced the rock 'n' roll lifestyle. That stops you from growing, really. I feel like I'm a 42-year-old man who's about 16 years younger and still getting to know myself. Ten or 15 years ago I thought the sun shone out of my ass. I was filled with bravado and supremely confident, which are qualities I do not carry around today."

Molko is still proud of his most recent work, though. That was the 2013 album Loud Like Love, a record still heavily present in their current setlists, and also an album that let Molko write in a different way. If his past songs were often strikingly confessional then Loud Like Love followed a path closer to short stories, all around the central concept of love. Molko believes it's a style of writing that actually let him have more freedom to be honest with his words.

"It's telling stories but it doesn't mean you're any less connected to it. You're using a literary device to express yourself, and paradoxically that can give you more freedom and let you be more vulnerable, because you're creating characters that embody your insecurities. When you write in a very confessional nature you can become self-conscious and hold back a bit."

That stylistic change also nods towards Molko believing that he has a better understanding of songwriting now, and of what's required to make a good tune.

"You don't need to be in love to write a love song, you just need to have been in love at some point," he explains. "You don't need to be sad to write a sad song - if you need to be feeling sad to write a sad song then you're probably not a good writer. It's a discipline, that's something I've come to understand over the years. Some people believe in this bogus theory of the lightning rod, that inspiration is going to channel into them like lightning in the middle of a storm - that's bull****.

"For me, writing's a journey of self discovery and a way to find out what's going inside of me emotionally. It's also a cathartic experience, a form of self-help or of therapy. I get to know myself better through doing it, and that's a good thing."

If Molko's own changes, such as going clean from drugs and becoming a father, seem to have helped him, there are certain musical changes that are greeted with his ire. The increasing trend of people using phones to record gigs has met with a frosty reception from some bands, and it's a gigging habit Molko simply can't understand.

"I don't mean to sound negative but when we first started, people would jump around and crowd-surf, and they were really connected, really in the moment," he reflects. "It was a huge adrenaline rush, and it's a shame that people are so intent on documenting the gig on their smart devices rather than experiencing the moment, which is completely fleeting and will never happen again...

"What that means for us, as a band, is that it's harder to connect with the audience, because they're not actually looking at you. The quality of what they are documenting it on is so bad that one is left wondering why they'd do it at all."

Hopefully their run of Scottish shows, part of a month-long tour, will avoid falling victim to too many camera-phone distractions. Both Molko and the group's tour manager have Scottish roots, and there will be an added local flavour to the gigs.

"We always love going to Scotland. My mum's from Dundee so it's a bit of a homecoming for me, and we've got a great new Scottish band from Dundee opening for us, called The Mirror Trap. We took them around Russia last year and they're growing into a really strong identity."

And while Placebo's own identity is mostly aimed at looking forwards, Molko admits they may make a few concessions to the past, particularly with the numbers they've previously banished from sets, in the way Radiohead rarely played their biggest hit Creep.

"At any given moment when you see us, we'll play whatever feels comfortable," he adds. "There's a possibility that when we're doing a 20-years tour, some of the unmentionables, which happen to be our biggest hits, will be resurrected. Some of our Creeps might appear again..."

Placebo play Edinburgh Corn Exchange on Saturday, Glasgow O2 Academy on Sunday and Aberdeen Music Hall on Monday.