Since almost the beginning of management research, we’ve known that social dynamics affect workplace Performance. Indeed, one of the pivotal questions of Gallup’s famous Employee engagement survey asks whether respondents “have a best friend at work.” But while friendship at work always being a good thing is a strong assumption, recent research suggests that having a close friend in the workplace might be more nuanced than we assume. There are definitely benefits, but there are also costs.

The research comes from a group of professors led by Jessica Methot of Rutgers University. Methot, along with colleagues Jeffery Lepine, Nathan Podsakoff, and Jessica Siegel Christian, studied the development of multiplex relationships inside companies to determine whether they were helpful or harmful to performance. Multiplex relationships refers to how one relationship or friendship might have multiple contexts. For example, if two people know each other as friends as well as coworkers, those are two different contexts.

In their study, the researchers surveyed 168 employees of an insurance company in the southeastern United States. The organization encouraged employees to get to know everyone else in the company by allowing employees to temporarily shift positions horizontally in the organization and to work with teams besides their usual ones. The researchers asked all employees surveyed for names of up to 10 coworkers to whom they go to for assistance with job challenges (a work-related tie). Then they asked the participants to list the names of up to 10 coworkers whom they consider friends (a personal tie). From there, they were able to turn the two lists into networks, and the two networks into one multiplex picture of the organization. They also asked employees questions about emotional exhaustion and the work environment itself. Lastly, four to six weeks after the survey the researchers asked the employees’ supervisors to fill out a performance appraisal.

Putting it all together, Methot and her colleagues (some of whom she’d probably label friends) could examine the network of the organization and how that network affected performance, burnout, and even how positive or negative the environment was. They found that multiplex relationships, driven by having a lot of coworkers who eventually developed into friends, significantly increased employees’ performance, as judged by their supervisor. One possible reason for this was people seeking advice. If you have friends in the company, it’s far easier to ask for help without fearing you’ll be judged a poor performer. In addition, having friends in the company, especially if they work in other departments, gives you access to information through informal networks you might not otherwise get. Another reason might be morale: Employees with close friends at work reported being in a good mood more often, which could spill over into positive effects on the work being performed.

But workplace friendship came with costs, the biggest perhaps being distraction. Impromptu discussions and extended breaks for socializing may slowly steal time, making it more stressful to complete work when we are focused. Having friends at work also triggered a higher rate of emotional exhaustion; keeping up with more and deeper relationships is tough. Those relationships can also be the source of stress when new opportunities, like promotions, present themselves. It’s much more likely that we’ll feel envious of people we’re close to. While the emotional toll itself decreased performance, the positive gains from having a coworker who is also a friend more than outweighed the negatives.

In a follow-up study, this one conducted across multiple companies in multiple industries, the researchers found a similar effect. Having coworkers also be friends might be a little more draining emotionally, but it makes us far more productive overall. “Workplace friends influence performance over and above purely instrumental or pure friendship-based relationships,” the authors write.

For organizations (and leaders), the challenge in this research is how to balance the benefits of encouraging employee friendship with the potential drawbacks of exhaustion.

Managers should make themselves more aware of the informal networks inside of their organization. Employees are using them not only for advice and performance-aiding interactions but also to develop friendships. Moreover, these informal networks are the areas where emotionally exhausting conversations tend to occur.

For individuals, the implications of this research are that we all need to become more mindful of how and where we are spending our time. Investing time in workplace friendships does pay off, especially when a quick chat can uplift and remotivate us. But too many quick chats — or chatting about the wrong subject, like envy of another colleague — can just as easily turn the benefits negative.

Overall, the positives of having a best friend at work appear to outweigh the negatives. By approaching it thoughtfully, managers and individuals can tip the scales toward even greater gains. If done right, business can benefit from being personal.