Davey's discussion of phobias is criticized because of the lack of distinctions between the various classes of phobias. Psychopharmacological evidence indicates differing pathophysiologies. Clinical psychopharmacological distinctions are not congruent with either a strict phylogenetic preparedness model or with cognitive biases. Davey's critique of the laboratory bred animal studies seems far fetched. His hypothesis concerning the importance of historical significance is clearly ad hoc rather than based on comparative data.

Specifying exact selection pressures for identifying adaptations is unnecessary. Novel behaviors are not spandrels since they can only develop because of prior functions. An adaptationist approach has a high prior probability, whereas spandrel hypotheses attempt to prove a negative. The concept of maladaptive spandrel is criticized. The utility of dysfunctional states for identification of adaptations gone wrong is emphasized.

We summarise a series of studies using a MAOI to help establish the validity of a subgroup of depressives referred to as atypical depressives. Patients with reactive mood meeting DSM-III criteria for depressive illness who had associated atypical features (which include hyperphagia, hypersomnolence, leaden paralysis, and rejection sensitivity) were randomised to imipramine, phenelzine and placebo. Non-responders were crossed over, and in all there were over 400 patient trials. Phenelzine consistently was found to be superior to imipramine. Only in trials which included patients lacking atypical, vegetative symptoms was imipramine found to equal phenelzine. We conclude that the researcher and the clinician should consider the relevance of the atypical depressive syndrome.

Evidence from a detailed investigation and review of the literature on monozygotic twins discordant for schizophrenia indicates that the schizophrenic index case was lighter in weight at birth than his co-twin (Stabenau and Pollin, 1967). Lane and Albee (1966) reported that schizophrenic singletons were significantly lighter in birth weight than their sibs.

Studies have clearly established that the concordance rate for schizophrenia is much higher in MZ than DZ twins. Beyond this, it is difficult to generalize the findings to singletons. Analyzing the reports of MZ twins discordant for schizophrenia, Stabenau and Pollin (1967) view the differences between the index case and his nonschizophrenic cotwin, as stemming from an early biological defect or immaturity, which, in interaction with parental handling and other environmental response, may lead to socio-psychological incompetency and, in turn, to gross schizophrenic symptomatology.

In a previous study (Pollack et al, 1966), comparing schizophrenic patients and their nonschizophrenic sibs, we found that patients showed significant psychological (social and personality) deviations from the preschool age through adolescence. We did not obtain significant differences on the biological and very early developmental variables that clearly distinguished the discordant twins. These include birth weight, paranatal complications or motor development, such as age of walking. In contrast, Lane and Albee (1966) found schizophrenic index cases to be lighter at birth than their sibs, confirming the finding for twins. The clinical significance of this difference is debatable, since the index cases did not differ from national norms.