Lyrically, the record is focused on Sia struggling to deal with drug addiction and a misdiagnosis of bipolar disorder at the time, later rediagnosed as complex PTSD in 2019.

[1][2] 1000 Forms of Fear received generally favorable reviews from music critics, who praised Sia's vocals as well as the album's lyrical content.

Sia's solo version of "Elastic Heart", which was originally a collaboration with The Weeknd and Diplo, was released in January 2015, and reached the top 20 of the Hot 100.

1000 Forms of Fear earned Sia three ARIA Music Awards in 2014 and was listed as one of the best albums of 2014 by several publications, including The Boston Globe and Rolling Stone.

[5] "Titanium" was a commercial success worldwide, peaking within the top five of record charts in the United States, Australia and numerous European regions.

"[16] "Eye of the Needle" is a "military-march" piano ballad,[17] while "Hostage" is a new wave pop and ska track that features Sia's voice "cracking like a punk singer.

"[11][18] The sixth song, "Straight for the Knife", is instrumented by strings and lyrically details a tempestuous relationship: "But will someone find me swinging from the rafters / From hanging on your every word.

"[11][15] "Fair Game", where Sia sings "Watch me squirm baby, but you're just what I need,"[15] is a minimalist and string-laden song about the desire to find an equal partner.

[36] On 2 April 2015, a music video was released, starring Ziegler in the same blonde wig in front of a black background, contorting her face and using her hands to express a slew of emotions.

[38] A music video for the song was released on 7 January 2015 and features Ziegler in the same blonde wig dancing in a giant birdcage opposite actor Shia LaBeouf.

[47] On 4 July 2014, Sia made an appearance on Jimmy Kimmel Live!, where she performed "Chandelier", "Big Girls Cry" and "Elastic Heart".

[50] On 8 February 2015, Sia and Ziegler together with actress Kristen Wiig performed "Chandelier" in a room reminiscent of the video set on the 2015 Grammy Awards telecast.

The Boston Globe critic Sarah Rodman described the release as "dynamite,"[56] while Heather Phares from AllMusic called the album "the sound of [Sia] owning her success.

"[25] Writing for The Daily Telegraph, Helen Brown praised the album's production and "inspirational" lyrics showcasing Sia struggling to deal with drug addiction and bipolar disorder.

[23] Rolling Stone's Julianne Escobedo Shepherd simply wrote that "she sounds like a superstar;"[19] while Maura Johnston of Spin characterised 1000 Forms of Fear as "a chunk of the human emotional spectrum committed to record.

"[17] On behalf of The New York Times, Jon Pareles lauded the "loopy, unresolved passions" on the album in favour of "the triumphal, laminated, computer-perfected tone of Sia’s clients.

"[15] Writing for Slant Magazine, Annie Galvin opined that 1000 Forms of Fear "should be the vessel that rockets the singer out of relative obscurity and into the stratosphere populated by those more recognizable stars who've come to dominate the pop-music universe thanks, in part, to her songwriting skills.

Club writer Annie Zaleski wrote: "1000 Forms of Fear certainly has the songs and contemporary sheen to make Sia a star in her own right, but it's at the expense of both her emotional intimacy and her offbeat personality.

[66] The Guardian's Clem Bastow commented on the album's success in the United States: "Australian artists typically fare better in the Billboard Hot 100 singles chart, but even then, Sia finds herself in rarefied company.

"[67] On behalf of The Sydney Morning Herald, George Palathingal opined that the album's debuting atop the Billboard 200 is the result of "a stroke of (anti-)marketing genius" and "a case of quality pop music standing proud.

[70] In the United Kingdom, 1000 Forms of Fear peaked at number 5 on the UK Albums Chart and was certified gold by the British Phonographic Industry.