Only recently has the concept of decision fatigue as a form of mental exhaustion become a subject of psychological study— decision fatigue acknowledges that

• decisions take mental energy
• that any given person has only a certain amount of mental energy
• that each decision a person makes uses some of this limited resource, and
• once this resource is exhausted, decision making turns to avoidance—

choosing the least effortful action in every case regardless of possible outcomes.

A recent study (2011) looked at boards granting parole in Israel.

Early in the day, the board was far more likely to grant parole for a prisoner with exactly the same record as a prisoner whose case came up later in the day. There was a slight return of decisions granting paroles right after lunch, but after a while, the simplest choice, No, became the automatic choice. (For more on the paralyzing effects of decision fatigue, see this NYT article.)

One is unlikely to have to make so many difficult decisions every day as a parole board, but the same principle holds for mundane tasks. Imagine the last time you spent hours shopping in a large store; there comes a moment when making considered decisions just become too hard; dismissiveness or automatic acquiesces takes over—“No. Nope. No. Sure. Yeah. That. Whatever. Don’t care.”—the need to get done overrides any thoughtful consideration.

Imagine then that every day becomes like that marathon shopping trip to a huge department store: every action, even the most straightforward, requires the same deliberation as choosing a new cell phone, or computer among dozens.

For a person who cannot make unconscious choices using emotionally driven heuristics, but instead must deliberate over every choice— even for simple, routine activities, fundamental to daily life—his or her ability to make any decision as all quickly depletes. Then, the easiest choice will always be chosen: no, I won’t do that. Or anything.

Withdrawal becomes the always best option. Life becomes too much. Too exhausting. Utterly draining mentally.

Work on my book? The words refuse to behave properly. I can’t make them.

Cook? I can’t figure out what to do with that.

What to wear? Easy: stay in my robe.

What do I want to do? NOTHING. Leave me alone.

Fortunately for me, the onset of these symptoms was sudden and complete.

Only a few days before, I felt nothing like this. I knew, intellectually, what it was to have passions, to be able to act quickly and decisively. I also knew something had affected me from the outside: a craniotomy had messed with my grey matter, and I was taking a drug that works specifically by altering brain function.

I had an enemy, a reason that was not me being broken inside.

One afternoon, I forced myself to research Keppra™ (levetiracetam). There it was. Under warnings:

If you use Keppra, you risk becoming aggressive, agitated, angry, anxious, depressed, or apathetic. You might also experience depersonalization or develop a personality disorder. [Emphasis mine.]

There are no indications for who will react like this, nor is the mechanism for those roughly 6 percent of us who develop these symptoms understood. Somehow, the chemistry of the drug interacts catastrophically with our brain chemistry; it blows up our personalities. There is even such a beast as “levetiracetam psychosis.”

I called my neurologist and told him to change my anti-seizure meds. That evening I took my old friend phenytoin.

Within 24 hours I felt reborn.

I cared. About many, many, many things. I could act, quickly, and without deliberating endlessly about all manner everyday actions. Life not longer exhausted me.

Then I thought I knew what depression was about, what those people in the case studies I’d read were speaking about.

But a broken ankle years later would show me another face of depression that I felt like scraping off my skin and more closely mapped what I knew about feeling despair.

Up Next: Better Living Through Chemistry: Notes from Chemically Induced Depression Part 5 of 6 (A Second Face of Depression: Vimpat™.)

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