So much for the sisterhood: Does novelist Janice Galloway hate women?

It's been said to me, emphatically, several times over the years and by a variety of different people: "Janice Galloway doesn't like women." Yet she's a woman who has been writing books about women ever since the late 1980s. The first time I ever saw Galloway read was almost 20 years ago at a feminist conference at Glasgow University. So why do people say she "doesn't like women"?

Saltcoats-born Galloway's first novel, The Trick is to Keep Breathing, launched her into the literary world with a plethora of prizes and nominations in 1989. After three novels and two collections of short stories, she has just published This is Not About Me, the blistering, terrifying, always moving first volume of an intended two-part memoir.

Women dominate the lime-and-turquoise cover: a young Galloway is squashed between her elder sister and her mother, two powerful personalities who framed her early life and are still framing it now. Her father was an alcoholic, soon abandoned; Janice and her mother left home and took refuge in a tiny upstairs room. On her father's death, they returned to the marital home and a surprise: the prodigal daughter, Janice's manic, terrifying elder sister, Cora.

"I made myself into a character. I changed my name," Galloway tells me. We're having coffee in Glasgow's Mitchell Library – well, I'm having tea and Galloway's having a coffee she bought herself. After the interview, she buys us both another while we wait for the photographer. I don't think I've interviewed anyone who bought their own before. It wasn't hard to recognise her – I interviewed her six years ago for the exceptional work she published that year, the superlative novel Clara. It won the 2004 Saltire Book of the Year award, and how it didn't sweep up every other major literary award going is something I will never understand. Galloway was tired when I met her then – Clara, she tells me today, took a lot out of her. I bet it did. At that time, Galloway was the single mother of a young son, living in the east end of Glasgow (she's married now, and living just outside the city). She worked during the night when she found it easiest to write. So it wasn't surprising that she looked tired that day.

Today, though, a quite different woman is before me, tossing back thick, glossy hair. She's wearing a fitted patterned blouse, dark pencil skirt, fishnet tights, high heels, and lots of make-up, subtly done. Galloway isn't tired at all. If anything, she's slightly nervy, the way someone is when they've had too much caffeine (something she worries about). She's warm, direct, not one to shy away from looking you in the eye, and most of all, happy.

She's explaining her unusual choice to change her own name to "Jeanette" for the purposes of writing the memoir. "It gave me a bit of distance," she explains. "It was a struggle to remember me being there, which is what gave me the licence to reconstruct conversations which I couldn't possibly have remembered. It was like writing Clara, only I had to change myself into a character and then come back. It was a ruthless kind of double-writing. And when I got to the end, I changed me back and changed everybody else's name by one letter, to give them a bit of distance." So her sister, Cora, isn't Cora? "No, she's Nora. I know she's dead, but I wanted to give her that distance."

Nora/Cora terrified me throughout the book, I tell her. The fiercely glamorous young woman on the front cover is every bit as scary as she looks. Galloway says when she was told her sister had died, in 2000, she went to the funeral "in trepidation", half expecting it to be some kind of joke.

"I was very conscious that Nora didn't like women – she wouldn't read books by women, now what the hell was that about? – and that my mother blamed women. She was very sympathetic to women like herself. But she'd say things like 'if there were nae bad women there'd be nae bad men.' I thought, I'm going to make a conscious effort to like women. There must be more to it than that. Nora could pack a punch, drink any man under the table. I couldn't do that, and I didn't want to be like my mother, so maybe I could have women friends."

She admits that Nora very probably suffered from manic depression, and her mother from depression – Galloway recounts an episode in the book when she came home to find her mother being rushed to hospital after taking an overdose – and reflects briefly on her own experiences, "out of control" in her late twenties, when she spent time in a psychiatric hospital.

"It was shortly after that that I started writing. It taught me that I didn't like being like this and I'd like it to stop. Smarten up, cheer up. And then deliberately trying to craft your life and make it better."

Did she worry about the exposure a memoir would entail? She dismisses that. "Everything you write is exposing. There's bags of stuff about me in Clara. There are short stories full of family stuff." It's funny, she says, how people think "memoir must be easier to write because you know the plot. But the plot doesn't matter, it's just a bribe to keep you writing. You're not writing because of the plot. You're writing because of the other stuff, the psychology of it; that's what interests me."

Did she wait until her mother and sister were both dead before writing the memoir?

"It wasn't as calculating as that. I don't think you choose to write books, they sort of turn up. I'm not one of those people who can turn out a book every three years. I have long pauses and long gaps of thinking. Certainly their dying [her mother died when Galloway was 26; she's 53 now] makes you reappraise who they were and what you were in particular. Because once they're gone, you begin to realise you're not the person you were yesterday."

Writing the memoir has made her realise that her sister's hardness, her brand of toughness, was "assiduously constructed". Nora, she says, "liked sex, men, a good time. Men took you out for a good time and offered you some kind of protection from the predatoriness that was out there when you went out dressed like that! There's no point in being a tomboy, not for a woman who likes men. She adopted that persona, not consciously... but something in her subconscious was choosing not to be what women were supposed to be like."

The amateur psychologist in me can't help wondering how much of a construction Galloway's appearance and manner are today, with this performance of femininity ("I like women and the things they like, I like girly chit-chat. I like that side of bonding with women, the fun and colourful side"). I don't mean that she's pretending, or being insincere. She's too direct for insincerity, and too serious, and too intelligent, to bother pretending. I don't think that's what it's about at all. But I do wonder if, in returning to her own name at the end of the memoir, in calling herself "Janice" when she gave her sister and mother different names to hide behind, if she's felt that she has, somehow, given something away, and if this new look, this extra-feminine construction, offers her some kind of protection.

When I see her read a week later at the Edinburgh Book Festival, dressed in a brightly coloured 1950s halter-neck dress, fishnet tights and black lace gloves, I get that feeling again – that she's dressing up. She's playing. Possibly, for the first time, Janice Galloway is actually having fun with who she is. Or who she isn't. After all, This Is Not About Her. This may well be about someone else entirely. And maybe that woman, the one who's had a reputation for so long for not liking other women, has always been someone else too.