He's part of one of the most famous, most watched, most talked-about families on the planet. But over the last year, Rob Kardashian - brother to Kim, Kourtney and Khloe - has all but disappeared from the media spotlight. And now in newly released clips from this week's episode of Keeping Up With The Kardashians his family have once again expressed their concern for the once gregarious but now reclusive 28-year-old. Scroll down for video . Rob Kardashian is rarely seen out and about and is thought to have struggled with his weight gain over the recent years . For it's been nearly a year since Rob seemed to vanish from the public eye. A former fixture on red carpets and social media, he now rarely tweets, his Instagram contains just one post and he is rarely pictured outside his house. It's a far cry from the fun loving Rob we were once used to seeing on our screens, when in the early series of KUWTK he would spend his days partying and larking about with his sisters. Confident and good looking Rob was even filmed trying out to be a model having been encouraged to do so by Kim. In 2008 he even took a spin on Dancing With The Stars - the popular US dancing equivalent to Strictly Come Dancing. But now multiple sources say that Rob is in a 'dark place,' and his sister Khloe has previously revealed that she believes her brother suffers from social anxiety. Rob was previously a regular at red carpet events, he is pictured here with Kim at the opening of the Seminole Hard Rock Hotel Casion in 2009 . Radar Online recently reported that Rob terrified his family last weekend when he didn't contact them for three days, bringing them close to calling the police. And there has long been speculation that Rob has long been tortured by his fame and uncomfortable with his family's increasing notoriety. Some point to December 2012, when his relationship with Rita Ora broke down, as the moment in which the cracks began to show. He took to Twitter to lambaste the singer accusing her of cheating on him. In tweets that he later deleted Rob said: 'She cheated on me with nearly 20 dudes while we were together... But I mean 20?!!!!' He later added: 'How can a woman who is so busy trying to start her own career have time to be with so many dudes while in a relationship?!' In happier days Rob posed with his sisters Kim, Kourtney and Khloe at a club in Las Vegas . Rob, pictured here with his whole family in 2011, used to be happy to be part of the Keeping Up With The Kardashians, however, he is no longer on the show . Rita responded to the tweets  saying: 'When you are involved with someone for a while and they decide to express their feelings to the public, well, that's not my personal way of therapy but I guess everyone takes split-ups differently… . 'You should have to sit an exam before you go on Twitter. To see if you're mentally stable.' She also said that she had never thought of their relationship as a serious boyfriend/girlfriend commitment. Rob cut a slim figure in 2012 but has since piled on the pounds, something he is said to have struggled with . Then last year Rob shocked onlookers when he decided to pull out of his own sister's wedding. When Kim married Kanye West in Italy last summer Rob was notably absent. Despite having traveled with his family to Europe he turned around at the last minute and went home. Kim has since revealed that he only told her of his decision on the morning of her big day. She said: 'He sent me a long email the morning of (the wedding), that he was going to leave. She added, 'I just thought, "You know what, this is my day. I'm not even going to worry about it".' It has been widely speculated that Rob's current lack of confidence comes from his weight and that he didn't attend the nuptials because he was worried about being photographed. Over the last few years the star has piled on the pounds and in episodes of KUWTK filmed before he departed from the show he was often heard talking about his weight. Rob shocked his Instagram followers when he posted this picture of Amy Adams character from Gone Girl saying that it was his sister Kim . On several occasions he went on diets and his sisters tried to help him lose the pounds and stay away from his beloved fast food, but nothing seemed to work. And whilst the man himself is yet to comment on his disappearance, his family have been quite vocal about his issues. His elder sister Khloe has previously revealed that she believes that Rob suffers from social anxiety. She said: 'I just feel, especially over the last year, Rob has become very introverted and has a kind of social anxiety. 'He's definitely not at his happiest place that he once was, and I know he can get to that happy place and he will. 'We all kind of get to a place where you don't know where to go in life or whatever, so I think it's important for him to know that he always has people to lean on and it's not unnatural for people to not know where to begin. It's a growing process. 'I will always be his number one supporter.' In a new episode of Keeping Up With The Kardashians Rob's Mother Kris (left) and his sister Kim (right) are seen arguing about how best to handle him . Rob was a popular member of the KUWTK cast but he is now rarely seen on the show . In clips from this week's show the family are once again seen discussing how best to help him. In one clip Kris says that the family has 'all the resources in the world,' to help her son. However, Kim is less kind, butting into the conversation and telling her mum and Khloe: 'Now what we have to do is everyone back off.' She continues: 'Everyone licks Rob's ass and does everything he says and it's just at some point you have to give it up. 'We all make his life so easy: "Okay we'll drive you around with a chauffeur so no one has to look at you." We had a chef on standby, a trainer, we'll send people to run out and buy you socks and underwear. 'Like this is pathetic. We're not going to cater to him any more but it has to be all of us.' Kris suggests 'maybe he can't help himself,' but Kim quickly replies: 'No he is still competent to where he can ask for help when he needs it.' Rob poses with his sister Kourtney (left) and his Mum and sister Kim (right) Rob cut a lonely figure when he was spotted at his Malibu home . Although neither of them have commented on it it seems things have been rather frosty between Kim and Rob of late. Rob recently raised eyebrows when he posted a picture of Amy Adams character in Gone Girl to his Instagram with the cryptic caption: 'This is my sister kim , the b**** from Gone Girl...' In a further clip from the hit reality TV show Kris told Khloe how she would like to help her troubled son. The matriarch said: 'I'm really, really, really worried about Rob. 'I talked to this guy that came highly recommended and he seems to think that everything I described about Rob is textbook and that he could come with all the proper people and help him but do it at home.' However the youngest Kardashian sibling still lives with Khloe, who  expressed her reservations. She said: 'So now you guys want to now have an outsider come in and ambush Rob  and basically ambush me. 'Neither you, nor Kourtney, nor Kim have even like attempted to see him for numerous days in a row. Do you even know his daily routines? Anything? No because you guys aren't there.' However, in a final clip released from the show it seems Khloe is as desperate as her mother to get him some help. The 30-year-old is seen taking a break from a hike to call her brother. Although Rob's side of the conversation can not be heard it is clear that it is causing Khloe some distress as she starts crying. 'You leave every facility that we take you to,' she is seen telling him on a phone call. And at the end of the call she exclaims: 'Just accept the f***ing help!'
Rob Kardashian, 28, has taken disappeared from the media spotlight . His sister Khloe says he has 'social anxiety' Family discuss him in new episode of Keeping Up With The Kardashians .