“If the dude in the next cubicle doesn’t turn down his freaking iPod, I’m going to throw myself a nervous breakdown.”

We all like to goof about how work makes us whacko. But mental illness isn’t a joke for one in five workers. That’s right: 20% of Americans suffer some form of mental disability, and that stat extends right into the workplace.

Work in Progress: How does mental illness affect the ability to work?Stephen P. Hinshaw: Let me pause and say there are many forms of mental illness; depression is different from schizophrenia. But many forms erode a person’s sense of hope. Life seems to be a huge burden. It’s hard to get motivated and stay focused. Some forms can rob a person of energy and organization. Again, with treatment, these kinds of symptoms and impairments are often readily handled. The stereotype that mental illnesses are impervious to help is just wrong.

WIP: What are the most common forms of mental illness that afflict American workers?SPH: Depression. It can be quite severe and can lead to suicidal thoughts or actions, but it is also surprisingly common. It is twice as frequent in women as in men. Women have a lifetime risk for depression of over 20%. On any given day, one in five women will experience a major depression. Men suffer it about half as much.

Another common form [of mental illness among working adults] is substance abuse. This is controversial; we’ve wondered for thousands of years if the overzealous use of illicit substances is an illness or a behavior that can be controlled. There are many forms of mental illness, including bipolar disorder and depression, that are associated with substance abuse. It can be a way to deal with the disorder. It can also temporarily mask symptoms of mental illness, though in the long term the effects of abuse end up exacerbating rather than masking them.

Anxiety disorder is another common illness [among workers]. It can range from fairly mild phobias to agoraphobia to panic attacks. It can restrict the range of territory a person can cover. If somebody has a panic attack, the feeling is similar to literally having a heart attack. Most people will somewhat reasonably say, I’ll do anything to prevent another one from occuring. Some find safe harbors or islands of safety; they say, I’m not going to drive past a certain point, or, eventually, I won’t leave my home. That’s due to the terror of having another panic attack. Quite obviously, this has major implications for work.

WIP: Are any of these conditions brought about by work?SPH: Well, I’ll frame it this way. Much of work and much of life involves stress. Many major forms of mental illness have some genetic predisposition. But none are caused by a single gene, hence in none of them is genetic cause sufficient. And so if one has genetic liability, it may well be that life stress and work stress pushes them over the threshold into a range of mental illness.

WIP: How does mental illness among workers affect the employer?SPH: Employers are in a bind. Employers want to maintain the productivity of their workplace; yet they have to be sensitive to the morale of employees. They are subject to stereotypes about mental illness that exist in our culture, meaning they’re predisposed to believe mental illness is permanent, hopeless and threatening.

Of course, modern day employers recognize there’s legislation to prevent discrimination, most notably the Americans with Disabilities Act. Recent statistics tell us that under the provisions of the ADA, at least 95% of workplace accommodations that are made have to do with accommodating for a wheelchair, visual impairments and other physical disabilities. Under 5% have anything to do with accommodating a mental disorder.

WIP: Should workers disclose their mental illness to their employer?SPH: It’s a tough call. Unlike many physical disabilities, mental ones are hidden. If I’m in a wheelchair, it’s quite apparent. If I have a history of depression, I can choose to tell you or not. Many prospective employees are afraid they’ll never get the job if they make such an admission. And many employees are quite loathe to disclose a mental illness to an employer. But then they forgo the possibility of reasonable accommodation if such an admission is made. Most accommodations an employer might make are relatively low cost and easy to implement: flexible work time, allowing leave to see a therapist, different kinds of supervisory arrangements. The irony is that by failing to disclose their condition, the employee promotes secrecy and shame–and prevents accommodations that might help everybody.

WIP: How often does mental illness lead to job loss?SPH: Statistics are hard to pin down, but what we hear is alarming. One third to a half are at risk of having to scale back so much as to be underemployed or unemployed.

WIP: How have employers dealt with mental illness among their workers in the past? And how have attitudes changed?SPH: Employers have responded in a thousand different ways. If confronted with erratic behavior, they were quite likely to decide the person is unmotivated or otherwise unfit for the job. In the final chapters of this book, I address how many levels of change could come together. If we have a different set of media images about mental illness, if we have legislation that mandates equitable coverage for treatment, if we have a society that is open to frank discussion of pain of mental illness rather than banishing to the back burner–then employers may recognize that openness about the topic and the provision of reasonable accommodation will benefit the company, the worker and the morale of everyone. What we have now is such an either-or dichotomous view: you’re either productive and working or irrational and not working.

WIP: Tell us about the Paul Wellstone Mental Health Equitable Treatment Act.SPH: In 1996, Congress passed and President Clinton signed the Mental Health Parity Act. This was a first step toward guaranteeing equal coverage for mental disorders on a par with physical disorders. There are, however, major loopholes in the 1996 legislation. Some of these have to do with the size of firms that are under its provisions; some have to do with limits on coverage. The bottom line is there is a decided lack of parity even under the provisions of this act. The Paul Wellstone Act seems to close up many of those loopholes. In the interim, three-fourths of states have passed their own parity legislation–but exempt from those state acts are the millions of self-employed individuals who aren’t on state plans. And symbolically, federal passage could really send a message that mental illness is real and treatment is of vital import.