Jennifer Lawrence is also nominated for best actress at the Oscars
Silver Linings Playbook took four awards at the Independent Spirit Awards in Santa Monica on Saturday.
The film - up for eight Oscars on Sunday - won best film, best screenplay, best director for David O Russell and best actress for Jennifer Lawrence at the indy film awards.
John Hawkes took best actor for the part of the late disabled journalist and poet Mark O'Brien in The Sessions.
Hawkes said he hoped the film would help change perceptions of disability.
"Mark O'Brien said as a disabled man he felt invisible to people. I hope this film can change that a little bit and we all see each other a little more," he told the audience in his acceptance speech.
His co-star Helen Hunt - who plays a sex therapist in the film based on an article written by O'Brien in 1990 - won best supporting actress.
Up for the same award at the Oscars, Hunt said backstage: "I'm proud of the movie, I can't believe we got it made."
Matthew McConaughey, who was also nominated for best actor for Killer Joe, picked up the best supporting actor prize for Magic Mike, which he stars in alongside his mother.
He praised the process of making indy films: "The vitality you get from not having enough money and not having enough time… that's what I love about independent films".
Best foreign film went to Oscar favourite Amour, directed by Michael Haneke.
"I feel wonderful, it comes as a complete surprise," he said, after collecting his award.
"No-one would think a film dealing with ageing and death (would do so well)."
Best documentary went to The Invisible War, which addresses rape and sexual abuse in the US military.
Producer Amy Ziering made an emotional speech: "This award says to our service members - you are heard, you are not alone and you are no longer invisible."
Like Silver Linings, Wes Anderson's Moonrise Kingdom was up for five awards but went away empty-handed.
'Superstitious but happy'
Accepting the best screenplay award for Silver Linings, Russell said: "The last time I held one of these was 19 years ago for best screenplay and best first feature and my son was one year's old - Matthew's here today and he gave me this movie."
Russell's son has bipolar disorder and was the inspiration for the film, which features Bradley Cooper's character dealing with the same illness.
Speaking backstage of the his Oscar chances, Russell said: "I'm very superstitious so I'm just very happy to be there."
Beasts of the Southern Wild picked up one award out of a possible four for British cinematographer Ben Richardson.
He said nine-year-old Oscar nominee Quvenzhane Wallis was the reason he took on the job.
"It was incredibly eye-opening, I could just see what she was going to do. Her performance is just incredible," he said.
The best first feature prize went to Perks of Being a Wallflower, starring Emma Watson.
Presenters included Daniel Radcliffe, Salma Hayek and Jeremy Renner.