That's pretty much impossible, give it another decade and thinking you don't have any mental health issues will be called being in denial. Now how many mental health issues are really a spiritual issue is another question entirely, but the whole mental health framework breaks down if we admit that there's spiritual forces out there that are real and can affect us.
And before I get flamed, yes there are real issues ( physical, spiritual, and emotional) that affect the proper function of the mind as well as the scars and coping mechanisms we pick up just living life in a fallen and destructive world. But I'm suspicious of the current trend to call almost any deviation from a standardized normal a mental health issue that needs drugs or professional counseling to treat.
Mental illness is definitely a hot topic now. However, just because mental illness is being diagnosed more doesn't mean it's suddenly more common. A lot of mental illness went undiagnosed in the past the same way a lot of physical conditions went undiagnosed. More than a million people are diagnosed with cancer each year: this is a fact, not some sinister scheme or trend. While it may seem like these numbers are rising, it could be the result of a variety of things such as more awareness, better access to healthcare or more available data. I definitely understand why the sudden rise of diagnoses is shocking or even scary. It is: it shows us how prevalent mental illness is (and has always been) in our world. Not unlike cancer or diabetes or any other health issue, mental illness is real and should be treated. Whether with medication, therapy, or alternative medicine is ultimately the choice of the person who has been diagnosed.
I do agree that spiritual issues can affect mental health, but that doesn't explain all mental illness. That gets into dangerous territory: we could start saying any health issue, physical or mental, is the result of personal sin or the like. If you wouldn't tell a person with asthma or chronic pain that their ailment is the result of a spiritual issue, you probably shouldn't say that about mental disorders either. There's nothing wrong with being mentally ill just like there's nothing wrong with being physically ill. While it is true that some mental disturbances are the result of things like demonic oppression, a diagnosis (and treatment) can help differentiate the two. If the treatment works for someone, good for them. If not, maybe it is a spiritual issue. I am of the firm belief that we should use the tools (both spiritual and clinical) available to us!