The recent article on mobile telephone software applications (apps) in mental health practice ^{Reference Marley and Farooq1} highlights many potential benefits of smartphone apps for mental health but also inadvertently demonstrates the challenges beyond what the authors may have realised. The paper refers readers to the National Health Service (NHS) Health Apps Library (http://apps.nhs.uk) when discussing psychological apps. However, in recent months the Library has been closed amid serious concerns that apps featured on the site may not be clinically effective ^{Reference Leigh and Flatt2} and may suffer from both security and privacy flaws that left patient data exposed. ^{Reference Wicks and Chiauzzi3} This rapid change in the smartphone apps landscape came suddenly and rapidly and demonstrates how much we still do not know about using this technology for healthcare. What we do know is that a firm foundation in privacy, security and efficacy is critical. Just as we demand clinical evidence and safety data when considering a new medication, we should also demand the same high standards when considering a new app. The potential of smartphone apps for mental health is as bright as the authors allude to, but the challenges are turning out to also be greater than many realised.